The NetCDF Fortran 77 Interface Guide
*************************************
This document describes the FORTRAN-77 interface to the netCDF library.
This document applies to netCDF version 4.1.1. This document was last
updated in 25 March 2010.
For a complete description of the netCDF format and utilities see
*note Top: (netcdf)Top.
1 Use of the NetCDF Library
***************************
You can use the netCDF library without knowing about all of the netCDF
interface. If you are creating a netCDF dataset, only a handful of
routines are required to define the necessary dimensions, variables,
and attributes, and to write the data to the netCDF dataset. (Even less
are needed if you use the ncgen utility to create the dataset before
running a program using netCDF library calls to write data. *Note
ncgen: (netcdf)ncgen.) Similarly, if you are writing software to
access data stored in a particular netCDF object, only a small subset
of the netCDF library is required to open the netCDF dataset and access
the data. Authors of generic applications that access arbitrary netCDF
datasets need to be familiar with more of the netCDF library.
In this chapter we provide templates of common sequences of netCDF
calls needed for common uses. For clarity we present only the names of
routines; omit declarations and error checking; omit the type-specific
suffixes of routine names for variables and attributes; indent
statements that are typically invoked multiple times; and use ... to
represent arbitrary sequences of other statements. Full parameter lists
are described in later chapters.
1.1 Creating a NetCDF Dataset
=============================
Here is a typical sequence of netCDF calls used to create a new netCDF
dataset:
NF_CREATE ! create netCDF dataset: enter define mode
...
NF_DEF_DIM ! define dimensions: from name and length
...
NF_DEF_VAR ! define variables: from name, type, dims
...
NF_PUT_ATT ! assign attribute values
...
NF_ENDDEF ! end definitions: leave define mode
...
NF_PUT_VAR ! provide values for variable
...
NF_CLOSE ! close: save new netCDF dataset
Only one call is needed to create a netCDF dataset, at which point
you will be in the first of two netCDF modes. When accessing an open
netCDF dataset, it is either in define mode or data mode. In define
mode, you can create dimensions, variables, and new attributes, but you
cannot read or write variable data. In data mode, you can access data
and change existing attributes, but you are not permitted to create new
dimensions, variables, or attributes.
One call to NF_DEF_DIM is needed for each dimension created.
Similarly, one call to NF_DEF_VAR is needed for each variable creation,
and one call to a member of the NF_PUT_ATT family is needed for each
attribute defined and assigned a value. To leave define mode and enter
data mode, call NF_ENDDEF.
Once in data mode, you can add new data to variables, change old
values, and change values of existing attributes (so long as the
attribute changes do not require more storage space). Single values may
be written to a netCDF variable with one of the members of the
NF_PUT_VAR1 family, depending on what type of data you have to write.
All the values of a variable may be written at once with one of the
members of the NF_PUT_VAR family. Arrays or array cross-sections of a
variable may be written using members of the NF_PUT_VARA family.
Subsampled array sections may be written using members of the
NF_PUT_VARS family. Mapped array sections may be written using members
of the NF_PUT_VARM family. (Subsampled and mapped access are general
forms of data access that are explained later.)
Finally, you should explicitly close all netCDF datasets that have
been opened for writing by calling NF_CLOSE. By default, access to the
file system is buffered by the netCDF library. If a program terminates
abnormally with netCDF datasets open for writing, your most recent
modifications may be lost. This default buffering of data is disabled
by setting the NF_SHARE flag when opening the dataset. But even if this
flag is set, changes to attribute values or changes made in define mode
are not written out until NF_SYNC or NF_CLOSE is called.
1.2 Reading a NetCDF Dataset with Known Names
=============================================
Here we consider the case where you know the names of not only the
netCDF datasets, but also the names of their dimensions, variables, and
attributes. (Otherwise you would have to do "inquire" calls.) The order
of typical C calls to read data from those variables in a netCDF
dataset is:
NF_OPEN ! open existing netCDF dataset
...
NF_INQ_DIMID ! get dimension IDs
...
NF_INQ_VARID ! get variable IDs
...
NF_GET_ATT ! get attribute values
...
NF_GET_VAR ! get values of variables
...
NF_CLOSE ! close netCDF dataset
First, a single call opens the netCDF dataset, given the dataset
name, and returns a netCDF ID that is used to refer to the open netCDF
dataset in all subsequent calls.
Next, a call to NF_INQ_DIMID for each dimension of interest gets the
dimension ID from the dimension name. Similarly, each required variable
ID is determined from its name by a call to NF_INQ_VARID.Once variable
IDs are known, variable attribute values can be retrieved using the
netCDF ID, the variable ID, and the desired attribute name as input to
a member of the NF_GET_ATT family (typically NF_GET_ATT_TEXT or
NF_GET_ATT_DOUBLE) for each desired attribute. Variable data values can
be directly accessed from the netCDF dataset with calls to members of
the NF_GET_VAR1 family for single values, the NF_GET_VAR family for
entire variables, or various other members of the NF_GET_VARA,
NF_GET_VARS, or NF_GET_VARM families for array, subsampled or mapped
access.
Finally, the netCDF dataset is closed with NF_CLOSE. There is no need
to close a dataset open only for reading.
1.3 Reading a netCDF Dataset with Unknown Names
===============================================
It is possible to write programs (e.g., generic software) which do such
things as processing every variable, without needing to know in advance
the names of these variables. Similarly, the names of dimensions and
attributes may be unknown.
Names and other information about netCDF objects may be obtained from
netCDF datasets by calling inquire functions. These return information
about a whole netCDF dataset, a dimension, a variable, or an attribute.
The following template illustrates how they are used:
NF_OPEN ! open existing netCDF dataset
...
NF_INQ ! find out what is in it
...
NF_INQ_DIM ! get dimension names, lengths
...
NF_INQ_VAR ! get variable names, types, shapes
...
NF_INQ_ATTNAME ! get attribute names
...
NF_INQ_ATT ! get attribute values
...
NF_GET_ATT ! get attribute values
...
NF_GET_VAR ! get values of variables
...
NF_CLOSE ! close netCDF dataset
As in the previous example, a single call opens the existing netCDF
dataset, returning a netCDF ID. This netCDF ID is given to the NF_INQ
routine, which returns the number of dimensions, the number of
variables, the number of global attributes, and the ID of the unlimited
dimension, if there is one.
All the inquire functions are inexpensive to use and require no I/O,
since the information they provide is stored in memory when a netCDF
dataset is first opened.
Dimension IDs use consecutive integers, beginning at 1. Also
dimensions, once created, cannot be deleted. Therefore, knowing the
number of dimension IDs in a netCDF dataset means knowing all the
dimension IDs: they are the integers 1, 2, 3, ... up to the number of
dimensions. For each dimension ID, a call to the inquire function
NF_INQ_DIM returns the dimension name and length.
Variable IDs are also assigned from consecutive integers 1, 2, 3,
... up to the number of variables. These can be used in NF_INQ_VAR
calls to find out the names, types, shapes, and the number of
attributes assigned to each variable.
Once the number of attributes for a variable is known, successive
calls to NF_INQ_ATTNAME return the name for each attribute given the
netCDF ID, variable ID, and attribute number. Armed with the attribute
name, a call to NF_INQ_ATT returns its type and length. Given the type
and length, you can allocate enough space to hold the attribute values.
Then a call to a member of the NF_GET_ATT family returns the attribute
values.
Once the IDs and shapes of netCDF variables are known, data values
can be accessed by calling a member of the NF_GET_VAR1 family for single
values, or members of the NF_GET_VAR, NF_GET_VARA, NF_GET_VARS, or
NF_GET_VARM for various kinds of array access.
1.4 Adding New Dimensions, Variables, Attributes
================================================
An existing netCDF dataset can be extensively altered. New dimensions,
variables, and attributes can be added or existing ones renamed, and
existing attributes can be deleted. Existing dimensions, variables, and
attributes can be renamed. The following code template lists a typical
sequence of calls to add new netCDF components to an existing dataset:
NF_OPEN ! open existing netCDF dataset
...
NF_REDEF ! put it into define mode
...
NF_DEF_DIM ! define additional dimensions (if any)
...
NF_DEF_VAR ! define additional variables (if any)
...
NF_PUT_ATT ! define other attributes (if any)
...
NF_ENDDEF ! check definitions, leave define mode
...
NF_PUT_VAR ! provide new variable values
...
NF_CLOSE ! close netCDF dataset
A netCDF dataset is first opened by the NF_OPEN call. This call puts
the open dataset in data mode, which means existing data values can be
accessed and changed, existing attributes can be changed (so long as
they do not grow), but nothing can be added. To add new netCDF
dimensions, variables, or attributes you must enter define mode, by
calling NF_REDEF.In define mode, call NF_DEF_DIM to define new
dimensions, NF_DEF_VAR to define new variables, and a member of the
NF_PUT_ATT family to assign new attributes to variables or enlarge old
attributes.
You can leave define mode and reenter data mode, checking all the new
definitions for consistency and committing the changes to disk, by
calling NF_ENDDEF. If you do not wish to reenter data mode, just call
NF_CLOSE, which will have the effect of first calling NF_ENDDEF.
Until the NF_ENDDEF call, you may back out of all the redefinitions
made in define mode and restore the previous state of the netCDF
dataset by calling NF_ABORT. You may also use the NF_ABORT call to
restore the netCDF dataset to a consistent state if the call to
NF_ENDDEF fails. If you have called NF_CLOSE from definition mode and
the implied call to NF_ENDDEF fails, NF_ABORT will automatically be
called to close the netCDF dataset and leave it in its previous
consistent state (before you entered define mode).
At most one process should have a netCDF dataset open for writing at
one time. The library is designed to provide limited support for
multiple concurrent readers with one writer, via disciplined use of the
NF_SYNC function and the NF_SHARE flag. If a writer makes changes in
define mode, such as the addition of new variables, dimensions, or
attributes, some means external to the library is necessary to prevent
readers from making concurrent accesses and to inform readers to call
NF_SYNC before the next access.
1.5 Error Handling
==================
The netCDF library provides the facilities needed to handle errors in a
flexible way. Each netCDF function returns an integer status value. If
the returned status value indicates an error, you may handle it in any
way desired, from printing an associated error message and exiting to
ignoring the error indication and proceeding (not recommended!). For
simplicity, the examples in this guide check the error status and call
a separate function to handle any errors.
The NF_STRERROR function is available to convert a returned integer
error status into an error message string.
Occasionally, low-level I/O errors may occur in a layer below the
netCDF library. For example, if a write operation causes you to exceed
disk quotas or to attempt to write to a device that is no longer
available, you may get an error from a layer below the netCDF library,
but the resulting write error will still be reflected in the returned
status value.
1.6 Compiling and Linking with the NetCDF Library
=================================================
Details of how to compile and link a program that uses the netCDF C or
FORTRAN interfaces differ, depending on the operating system, the
available compilers, and where the netCDF library and include files are
installed. Nevertheless, we provide here examples of how to compile and
link a program that uses the netCDF library on a Unix platform, so that
you can adjust these examples to fit your installation.
Every FORTRAN file that references netCDF functions or constants must
contain an appropriate INCLUDE statement before the first such
reference:
INCLUDE 'netcdf.inc'
Unless the netcdf.inc file is installed in a standard directory where
the FORTRAN compiler always looks, you must use the -I option when
invoking the compiler, to specify a directory where netcdf.inc is
installed, for example:
f77 -c -I/usr/local/netcdf/include myprogram.f
Alternatively, you could specify an absolute path name in the INCLUDE
statement, but then your program would not compile on another platform
where netCDF is installed in a different location.
Unless the netCDF library is installed in a standard directory where
the linker always looks, you must use the -L and -l options to link an
object file that uses the netCDF library. For example:
f77 -o myprogram myprogram.o -L/usr/local/netcdf/lib -lnetcdf
Alternatively, you could specify an absolute path name for the
library:
f77 -o myprogram myprogram.o -l/usr/local/netcdf/lib/libnetcdf.
2 Datasets
**********
2.1 Datasets Introduction
=========================
This chapter presents the interfaces of the netCDF functions that deal
with a netCDF dataset or the whole netCDF library.
A netCDF dataset that has not yet been opened can only be referred to
by its dataset name. Once a netCDF dataset is opened, it is referred to
by a netCDF ID, which is a small nonnegative integer returned when you
create or open the dataset. A netCDF ID is much like a file descriptor
in C or a logical unit number in FORTRAN. In any single program, the
netCDF IDs of distinct open netCDF datasets are distinct. A single
netCDF dataset may be opened multiple times and will then have multiple
distinct netCDF IDs; however at most one of the open instances of a
single netCDF dataset should permit writing. When an open netCDF
dataset is closed, the ID is no longer associated with a netCDF dataset.
Functions that deal with the netCDF library include:
* Get version of library.
* Get error message corresponding to a returned error code.
The operations supported on a netCDF dataset as a single object are:
* Create, given dataset name and whether to overwrite or not.
* Open for access, given dataset name and read or write intent.
* Put into define mode, to add dimensions, variables, or attributes.
* Take out of define mode, checking consistency of additions.
* Close, writing to disk if required.
* Inquire about the number of dimensions, number of variables,
number of global attributes, and ID of the unlimited dimension, if
any.
* Synchronize to disk to make sure it is current.
* Set and unset nofill mode for optimized sequential writes.
* After a summary of conventions used in describing the netCDF
interfaces, the rest of this chapter presents a detailed
description of the interfaces for these operations.
2.2 NetCDF Library Interface Descriptions
=========================================
Each interface description for a particular netCDF function in this and
later chapters contains:
* a description of the purpose of the function;
* a FORTRAN function prototype that presents the type and order of
the formal parameters to the function;
* a description of each formal parameter in the C interface;
* a list of possible error conditions; and
* an example of a FORTRAN program fragment calling the netCDF
function (and perhaps other netCDF functions).
The examples follow a simple convention for error handling, always
checking the error status returned from each netCDF function call and
calling a handle_error function in case an error was detected. For an
example of such a function, see Section 5.2 "Get error message
corresponding to error status: nf_strerror".
2.3 NF_STRERROR
===============
The function NF_STRERROR returns a static reference to an error message
string corresponding to an integer netCDF error status or to a system
error number, presumably returned by a previous call to some other
netCDF function. The list of netCDF error status codes is available in
the appropriate include file for each language binding.
Usage
=====
CHARACTER*80 FUNCTION NF_STRERROR(INTEGER NCERR)
`NCERR'
An error status that might have been returned from a previous call
to some netCDF function.
Errors
======
If you provide an invalid integer error status that does not correspond
to any netCDF error message or or to any system error message (as
understood by the system strerror function), NF_STRERROR returns a
string indicating that there is no such error status.
Example
=======
Here is an example of a simple error handling function that uses
NF_STRERROR to print the error message corresponding to the netCDF
error status returned from any netCDF function call and then exit:
INCLUDE 'netcdf.inc'
...
SUBROUTINE HANDLE_ERR(STATUS)
INTEGER STATUS
IF (STATUS .NE. NF_NOERR) THEN
PRINT *, NF_STRERROR(STATUS)
STOP 'Stopped'
ENDIF
END
2.4 Get netCDF library version: NF_INQ_LIBVERS
==============================================
The function NF_INQ_LIBVERS returns a string identifying the version of
the netCDF library, and when it was built.
Usage
=====
CHARACTER*80 FUNCTION NF_INQ_LIBVERS()
Errors
======
This function takes no arguments, and thus no errors are possible in
its invocation.
Example
=======
Here is an example using nf_inq_libvers to print the version of the
netCDF library with which the program is linked:
INCLUDE 'netcdf.inc'
...
PRINT *, NF_INQ_LIBVERS()
2.5 NF_CREATE
=============
This function creates a new netCDF dataset, returning a netCDF ID that
can subsequently be used to refer to the netCDF dataset in other netCDF
function calls. The new netCDF dataset opened for write access and
placed in define mode, ready for you to add dimensions, variables, and
attributes.
A creation mode flag specifies whether to overwrite any existing
dataset with the same name and whether access to the dataset is shared.
Usage
=====
INTEGER FUNCTION NF_CREATE (CHARACTER*(*) PATH, INTEGER CMODE,
INTEGER ncid)
`PATH'
The file name of the new netCDF dataset.
`CMODE'
The creation mode flag. The following flags are available:
NF_NOCLOBBER, NF_SHARE, NF_64BIT_OFFSET, NF_NETCDF4 and
NF_CLASSIC_MODEL. You can combine the affect of multiple flags in
a single argument by using the bitwise OR operator. For example,
to specify both NF_NOCLOBBER and NF_SHARE, you could provide the
argument OR(NF_NOCLOBBER, NF_SHARE).
A zero value (defined for convenience as NF_CLOBBER) specifies the
default behavior: overwrite any existing dataset with the same file
name and buffer and cache accesses for efficiency. The dataset
will be in netCDF classic format. *Note NetCDF Classic Format
Limitations: (netcdf)NetCDF Classic Format Limitations.
Setting NF_NOCLOBBER means you do not want to clobber (overwrite)
an existing dataset; an error (NF_EEXIST) is returned if the
specified dataset already exists.
The NF_SHARE flag is appropriate when one process may be writing
the dataset and one or more other processes reading the dataset
concurrently; it means that dataset accesses are not buffered and
caching is limited. Since the buffering scheme is optimized for
sequential access, programs that do not access data sequentially
may see some performance improvement by setting the NF_SHARE flag.
This only applied to classic and 64-bit offset format files.
Setting NF_64BIT_OFFSET causes netCDF to create a 64-bit offset
format file, instead of a netCDF classic format file. The 64-bit
offset format imposes far fewer restrictions on very large (i.e.
over 2 GB) data files. *Note Large File Support: (netcdf)Large
File Support.
Setting NF_NETCDF4 causes netCDF to create a netCDF-4/HDF5 format
file. Oring NF_CLASSIC_MODEL with NF_NETCDF4 causes the netCDF
library to create a netCDF-4/HDF5 data file, with the netCDF
classic model enforced - none of the new features of the netCDF-4
data model may be usedin such a file, for example groups and
user-defined types.
`ncid'
Returned netCDF ID.
Errors
======
NF_CREATE returns the value NF_NOERR if no errors occurred. Possible
causes of errors include:
* Passing a dataset name that includes a directory that does not
exist.
* Specifying a dataset name of a file that exists and also specifying
NF_NOCLOBBER.
* Specifying a meaningless value for the creation mode.
* Attempting to create a netCDF dataset in a directory where you
don't have permission to create files.
Example
=======
In this example we create a netCDF dataset named foo.nc; we want the
dataset to be created in the current directory only if a dataset with
that name does not already exist:
INCLUDE 'netcdf.inc'
...
INTEGER NCID, STATUS
...
STATUS = NF_CREATE('foo.nc', NF_NOCLOBBER, NCID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
2.6 NF__CREATE
==============
This function is a variant of NF_CREATE, NF__CREATE (note the double
underscore) allows users to specify two tuning parameters for the file
that it is creating. These tuning parameters are not written to the
data file, they are only used for so long as the file remains open
after an NF__CREATE.
This function creates a new netCDF dataset, returning a netCDF ID
that can subsequently be used to refer to the netCDF dataset in other
netCDF function calls. The new netCDF dataset opened for write access
and placed in define mode, ready for you to add dimensions, variables,
and attributes.
A creation mode flag specifies whether to overwrite any existing
dataset with the same name and whether access to the dataset is shared.
Usage
=====
INTEGER FUNCTION NF__CREATE (CHARACTER*(*) PATH, INTEGER CMODE, INTEGER INITIALSZ,
INTEGER BUFRSIZEHINT, INTEGER ncid)
`PATH'
The file name of the new netCDF dataset.
`CMODE'
The creation mode flag. The following flags are available:
NF_NOCLOBBER, NF_SHARE, NF_64BIT_OFFSET, NF_NETCDF4, and
NF_CLASSIC_MODEL.
Setting NF_NOCLOBBER means you do not want to clobber (overwrite)
an existing dataset; an error (NF_EEXIST) is returned if the
specified dataset already exists.
The NF_SHARE flag is appropriate when one process may be writing
the dataset and one or more other processes reading the dataset
concurrently; it means that dataset accesses are not buffered and
caching is limited. Since the buffering scheme is optimized for
sequential access, programs that do not access data sequentially
may see some performance improvement by setting the NF_SHARE flag.
This flag has no effect with netCDF-4/HDF5 files.
Setting NF_64BIT_OFFSET causes netCDF to create a 64-bit offset
format file, instead of a netCDF classic format file. The 64-bit
offset format imposes far fewer restrictions on very large (i.e.
over 2 GB) data files. *Note Large File Support: (netcdf)Large
File Support.
Setting NF_CLASSIC_MODEL causes netCDF to enforce the classic data
model in this file. (This only has effect for netCDF-4/HDF5 files,
as classic and 64-bit offset files always use the classic model.)
When used with NF_NETCDF4, this flag ensures that the resulting
netCDF-4/HDF5 file may never contain any new constructs from the
enhanced data model. That is, it cannot contain groups, user
defined types, multiple unlimited dimensions, or new atomic types.
The advantage of this restriction is that such files are
guarenteed to work with existing netCDF software.
A zero value (defined for convenience as NF_CLOBBER) specifies the
default behavior: overwrite any existing dataset with the same file
name and buffer and cache accesses for efficiency. The dataset
will be in netCDF classic format. *Note NetCDF Classic Format
Limitations: (netcdf)NetCDF Classic Format Limitations.
`INITIALSZ'
This parameter sets the initial size of the file at creation time.
`BUFRSIZEHINT'
The argument referenced by BUFRSIZEHINT controls a space versus
time tradeoff, memory allocated in the netcdf library versus
number of system calls.
Because of internal requirements, the value may not be set to
exactly the value requested. The actual value chosen is returned
by reference.
Using the value NF_SIZEHINT_DEFAULT causes the library to choose a
default. How the system chooses the default depends on the system.
On many systems, the "preferred I/O block size" is available from
the stat() system call, struct stat member st_blksize. If this is
available it is used. Lacking that, twice the system pagesize is
used.
Lacking a call to discover the system pagesize, we just set default
bufrsize to 8192.
The BUFRSIZE is a property of a given open netcdf descriptor ncid,
it is not a persistent property of the netcdf dataset.
`ncid'
Returned netCDF ID.
Errors
======
NF__CREATE returns the value NF_NOERR if no errors occurred. Possible
causes of errors include:
* Passing a dataset name that includes a directory that does not
exist.
* Specifying a dataset name of a file that exists and also specifying
NF_NOCLOBBER.
* Specifying a meaningless value for the creation mode.
* Attempting to create a netCDF dataset in a directory where you
don't have permission to create files.
Example
=======
In this example we create a netCDF dataset named foo.nc; we want the
dataset to be created in the current directory only if a dataset with
that name does not already exist:
INCLUDE 'netcdf.inc'
...
INTEGER NCID, STATUS, INITIALSZ, BUFRSIZEHINT
...
INITIALSZ = 2048
BUFRSIZEHINT = 1024
STATUS = NF__CREATE('foo.nc', NF_NOCLOBBER, INITIALSZ, BUFRSIZEHINT, NCID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
2.7 NF_CREATE_PAR
=================
This function is a variant of nf_create, nf_create_par allows users to
open a file on a MPI/IO or MPI/Posix parallel file system.
The parallel parameters are not written to the data file, they are
only used for so long as the file remains open after an nf_create_par.
This function is only available if the netCDF library was built with
parallel I/O.
This function creates a new netCDF dataset, returning a netCDF ID
that can subsequently be used to refer to the netCDF dataset in other
netCDF function calls. The new netCDF dataset opened for write access
and placed in define mode, ready for you to add dimensions, variables,
and attributes.
When a netCDF-4 file is created for parallel access, independent
operations are the default. To use collective access on a variable,
*Note NF_VAR_PAR_ACCESS::.
Usage
=====
INTEGER FUNCTION NF_CREATE_PAR(CHARACTER*(*) PATH, INTEGER CMODE,
INTEGER MPI_COMM, INTEGER MPI_INFO,
INTEGER ncid)
`PATH'
The file name of the new netCDF dataset.
`CMODE'
The creation mode flag. The following flags are available:
NF_NOCLOBBER, NF_NETCDF4 and NF_CLASSIC_MODEL. You can combine the
affect of multiple flags in a single argument by using the bitwise
OR operator. For example, to specify both NF_NOCLOBBER and
NF_NETCDF4, you could provide the argument OR(NF_NOCLOBBER,
NF_NETCDF4).
Setting NF_NETCDF4 causes netCDF to create a netCDF-4/HDF5 format
file. Oring NF_CLASSIC_MODEL with NF_NETCDF4 causes the netCDF
library to create a netCDF-4/HDF5 data file, with the netCDF
classic model enforced - none of the new features of the netCDF-4
data model may be usedin such a file, for example groups and
user-defined types.
Only netCDF-4/HDF5 files may be used with parallel I/O.
`MPI_COMM'
The MPI communicator.
`MPI_INFO'
The MPI info.
`ncid'
Returned netCDF ID.
Errors
======
NF_CREATE returns the value NF_NOERR if no errors occurred. Possible
causes of errors include:
* Passing a dataset name that includes a directory that does not
exist.
* Specifying a dataset name of a file that exists and also specifying
NF_NOCLOBBER.
* Specifying a meaningless value for the creation mode.
* Attempting to create a netCDF dataset in a directory where you
don't have permission to create files.
Example
=======
This example is from test program nf_test/ftst_parallel.F.
! Create the netCDF file.
mode_flag = IOR(nf_netcdf4, nf_classic_model)
retval = nf_create_par(FILE_NAME, mode_flag, MPI_COMM_WORLD,
$ MPI_INFO_NULL, ncid)
if (retval .ne. nf_noerr) stop 2
2.8 NF_OPEN
===========
The function NF_OPEN opens an existing netCDF dataset for access.
Usage
=====
INTEGER FUNCTION NF_OPEN(CHARACTER*(*) PATH, INTEGER OMODE, INTEGER ncid)
`PATH'
File name for netCDF dataset to be opened. This may be an OPeNDAP
URL if DAP support is enabled.
`OMODE'
A zero value (or NF_NOWRITE) specifies the default behavior: open
the dataset with read-only access, buffering and caching accesses
for efficiency.
Otherwise, the creation mode is NF_WRITE, NF_SHARE, or
OR(NF_WRITE, NF_SHARE). Setting the NF_WRITE flag opens the
dataset with read-write access. ("Writing" means any kind of
change to the dataset, including appending or changing data,
adding or renaming dimensions, variables, and attributes, or
deleting attributes.) The NF_SHARE flag is appropriate when one
process may be writing the dataset and one or more other processes
reading the dataset concurrently; it means that dataset accesses
are not buffered and caching is limited. Since the buffering
scheme is optimized for sequential access, programs that do not
access data sequentially may see some performance improvement by
setting the NF_SHARE flag.
`ncid'
Returned netCDF ID.
Errors
======
NF_OPEN returns the value NF_NOERR if no errors occurred. Otherwise,
the returned status indicates an error. Possible causes of errors
include:
* The specified netCDF dataset does not exist.
* A meaningless mode was specified.
Example
=======
Here is an example using NF_OPEN to open an existing netCDF dataset
named foo.nc for read-only, non-shared access:
INCLUDE 'netcdf.inc'
...
INTEGER NCID, STATUS
...
STATUS = NF_OPEN('foo.nc', 0, NCID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
2.9 NF__OPEN
============
The function NF)_OPEN opens an existing netCDF dataset for access, with
a performance tuning parameter.
Usage
=====
INTEGER FUNCTION NF__OPEN(CHARACTER*(*) PATH, INTEGER OMODE, INTEGER
BUFRSIZEHINT, INTEGER ncid)
`PATH'
File name for netCDF dataset to be opened.
`OMODE'
A zero value (or NF_NOWRITE) specifies the default behavior: open
the dataset with read-only access, buffering and caching accesses
for efficiency
Otherwise, the creation mode is NF_WRITE, NF_SHARE, or
OR(NF_WRITE,NF_SHARE). Setting the NF_WRITE flag opens the dataset
with read-write access. ("Writing" means any kind of change to the
dataset, including appending or changing data, adding or renaming
dimensions, variables, and attributes, or deleting attributes.)
The NF_SHARE flag is appropriate when one process may be writing
the dataset and one or more other processes reading the dataset
concurrently; it means that dataset accesses are not buffered and
caching is limited. Since the buffering scheme is optimized for
sequential access, programs that do not access data sequentially
may see some performance improvement by setting the NF_SHARE flag.
`BUFRSIZEHINT'
This argument controls a space versus time tradeoff, memory
allocated in the netcdf library versus number of system calls.
Because of internal requirements, the value may not be set to
exactly the value requested. The actual value chosen is returned
by reference.
Using the value NF_SIZEHINT_DEFAULT causes the library to choose a
default. How the system chooses the default depends on the system.
On many systems, the "preferred I/O block size" is available from
the stat() system call, struct stat member st_blksize. If this is
available it is used. Lacking that, twice the system pagesize is
used.
Lacking a call to discover the system pagesize, we just set default
bufrsize to 8192.
The bufrsize is a property of a given open netcdf descriptor ncid,
it is not a persistent property of the netcdf dataset.
`ncid'
Returned netCDF ID.
Errors
======
NF__OPEN returns the value NF_NOERR if no errors occurred. Otherwise,
the returned status indicates an error. Possible causes of errors
include:
* The specified netCDF dataset does not exist.
* A meaningless mode was specified.
Example
=======
Here is an example using NF__OPEN to open an existing netCDF dataset
named foo.nc for read-only, non-shared access:
INCLUDE 'netcdf.inc'
...
INTEGER NCID, STATUS, BUFRSIZEHINT
...
BUFRSIZEHINT = 1024
STATUS = NF_OPEN('foo.nc', 0, BUFRSIZEHINT, NCID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
2.10 NF_OPEN_PAR
================
This function opens a netCDF-4 dataset for parallel access.
This function is only available if the netCDF library was built with
a HDF5 library for which -enable-parallel was used, and which was
linked (like HDF5) to MPI libraries.
This opens the file using either MPI-IO or MPI-POSIX. The file must
be a netCDF-4 file. (That is, it must have been created using NF_NETCDF4
in the creation mode).
This function is only available if netCDF-4 was build with a version
of the HDF5 library which was built with -enable-parallel.
Before either HDF5 or netCDF-4 can be installed with support for
parallel programming, and MPI layer must also be installed on the
machine, and usually a parallel file system.
NetCDF-4 exposes the parallel access functionality of HDF5. For more
information about what is required to install and use the parallel
access functions, see the HDF5 web site.
When a netCDF-4 file is opened for parallel access, collective
operations are the default. To use independent access on a variable,
*Note NF_VAR_PAR_ACCESS::.
Usage
=====
INTEGER FUNCTION NF_OPEN_PAR(CHARACTER*(*) PATH, INTEGER OMODE,
INTEGER MPI_COMM, INTEGER MPI_INFO,
INTEGER ncid)
`PATH'
File name for netCDF dataset to be opened.
`OMODE'
A zero value (or NF_NOWRITE) specifies the default behavior: open
the dataset with read-only access.
Otherwise, the mode may be NF_WRITE. Setting the NF_WRITE flag
opens the dataset with read-write access. ("Writing" means any
kind of change to the dataset, including appending or changing
data, adding or renaming dimensions, variables, and attributes, or
deleting attributes.)
Setting NF_NETCDF4 is not necessary (or allowed). The file type is
detected automatically.
`MPI_COMM'
The MPI communicator.
`MPI_INFO'
The MPI info.
`ncid'
Returned netCDF ID.
Errors
======
NF_OPEN returns the value NF_NOERR if no errors occurred. Otherwise,
the returned status indicates an error. Possible causes of errors
include:
* The specified netCDF dataset does not exist.
* A meaningless mode was specified.
* Not a netCDF-4 file.
Example
=======
This example is from the test program nf_test/ftst_parallel.F.
! Reopen the file.
retval = nf_open_par(FILE_NAME, nf_nowrite, MPI_COMM_WORLD,
$ MPI_INFO_NULL, ncid)
if (retval .ne. nf_noerr) stop 2
2.11 NF_REDEF
=============
The function NF_REDEF puts an open netCDF dataset into define mode, so
dimensions, variables, and attributes can be added or renamed and
attributes can be deleted.
Usage
=====
INTEGER FUNCTION NF_REDEF(INTEGER NCID)
`NCID'
netCDF ID, from a previous call to NF_OPEN or NF_CREATE.
Errors
======
NF_REDEF returns the value NF_NOERR if no errors occurred. Otherwise,
the returned status indicates an error. Possible causes of errors
include:
* The specified netCDF dataset is already in define mode.
* The specified netCDF dataset was opened for read-only.
* The specified netCDF ID does not refer to an open netCDF dataset.
Example
=======
Here is an example using NF_REDEF to open an existing netCDF dataset
named foo.nc and put it into define mode:
INCLUDE 'netcdf.inc'
...
INTEGER NCID, STATUS
...
STATUS = NF_OPEN('foo.nc', NF_WRITE, NCID) ! open dataset
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
STATUS = NF_REDEF(NCID) ! put in define mode
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
2.12 NF_ENDDEF
==============
The function NF_ENDDEF takes an open netCDF dataset out of define mode.
The changes made to the netCDF dataset while it was in define mode are
checked and committed to disk if no problems occurred. Non-record
variables may be initialized to a "fill value" as well (*note
NF_SET_FILL::). The netCDF dataset is then placed in data mode, so
variable data can be read or written.
This call may involve copying data under some circumstances. *Note
File Structure and Performance: (netcdf)File Structure and Performance.
Usage
=====
INTEGER FUNCTION NF_ENDDEF(INTEGER NCID)
`NCID'
NetCDF ID, from a previous call to NF_OPEN or NF_CREATE.
Errors
======
NF_ENDDEF returns the value NF_NOERR if no errors occurred. Otherwise,
the returned status indicates an error. Possible causes of errors
include:
* The specified netCDF dataset is not in define mode.
* The specified netCDF ID does not refer to an open netCDF dataset.
The size of one or more variables exceed the size constraints for
whichever variant of the file format is in use). *Note Large File
Support: (netcdf)Large File Support.
*
Example
=======
Here is an example using NF_ENDDEF to finish the definitions of a new
netCDF dataset named foo.nc and put it into data mode:
INCLUDE 'netcdf.inc'
...
INTEGER NCID, STATUS
...
STATUS = NF_CREATE('foo.nc', NF_NOCLOBBER, NCID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
... ! create dimensions, variables, attributes
STATUS = NF_ENDDEF(NCID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
2.13 NF__ENDDEF
===============
The function NF__ENDDEF takes an open netCDF dataset out of define
mode. The changes made to the netCDF dataset while it was in define
mode are checked and committed to disk if no problems occurred.
Non-record variables may be initialized to a "fill value" as well
(*note NF_SET_FILL::). The netCDF dataset is then placed in data mode,
so variable data can be read or written.
This call may involve copying data under some circumstances. *Note
File Structure and Performance: (netcdf)File Structure and Performance.
This function assumes specific characteristics of the netcdf version
1 and version 2 file formats. Users should use nf_enddef in most
circumstances. Although this function will be available in future
netCDF implementations, it may not continue to have any effect on
performance.
The current netcdf file format has three sections, the "header"
section, the data section for fixed size variables, and the data
section for variables which have an unlimited dimension (record
variables).
The header begins at the beginning of the file. The index (offset) of
the beginning of the other two sections is contained in the header.
Typically, there is no space between the sections. This causes copying
overhead to accrue if one wishes to change the size of the sections, as
may happen when changing names of things, text attribute values, adding
attributes or adding variables. Also, for buffered i/o, there may be
advantages to aligning sections in certain ways.
The minfree parameters allow one to control costs of future calls to
nf_redef, nf_enddef by requesting that minfree bytes be available at
the end of the section.
The align parameters allow one to set the alignment of the beginning
of the corresponding sections. The beginning of the section is rounded
up to an index which is a multiple of the align parameter. The flag
value ALIGN_CHUNK tells the library to use the bufrsize (see above) as
the align parameter.
The file format requires mod 4 alignment, so the align parameters
are silently rounded up to multiples of 4. The usual call,
nf_enddef(ncid);
is equivalent to
nf_enddef(ncid, 0, 4, 0, 4);
The file format does not contain a "record size" value, this is
calculated from the sizes of the record variables. This unfortunate
fact prevents us from providing minfree and alignment control of the
"records" in a netcdf file. If you add a variable which has an
unlimited dimension, the third section will always be copied with the
new variable added.
Usage
=====
INTEGER FUNCTION NF_ENDDEF(INTEGER NCID, INTEGER H_MINFREE, INTEGER V_ALIGN,
INTEGER V_MINFREE, INTEGER R_ALIGN)
`NCID'
NetCDF ID, from a previous call to NF_OPEN or NF_CREATE.
`H_MINFREE'
Sets the pad at the end of the "header" section.
`V_ALIGN'
Controls the alignment of the beginning of the data section for
fixed size variables.
`V_MINFREE'
Sets the pad at the end of the data section for fixed size
variables.
`R_ALIGN'
Controls the alignment of the beginning of the data section for
variables which have an unlimited dimension (record variables).
Errors
======
NF__ENDDEF returns the value NF_NOERR if no errors occurred. Otherwise,
the returned status indicates an error. Possible causes of errors
include:
* The specified netCDF dataset is not in define mode.
* The specified netCDF ID does not refer to an open netCDF dataset.
* The size of one or more variables exceed the size constraints for
whichever variant of the file format is in use). *Note Large File
Support: (netcdf)Large File Support.
Example
=======
Here is an example using NF__ENDDEF to finish the definitions of a new
netCDF dataset named foo.nc and put it into data mode:
INCLUDE 'netcdf.inc'
...
INTEGER NCID, STATUS, H_MINFREE, V_ALIGN, V_MINFREE, R_ALIGN
...
STATUS = NF_CREATE('foo.nc', NF_NOCLOBBER, NCID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
... ! create dimensions, variables, attributes
H_MINFREE = 512
V_ALIGN = 512
V_MINFREE = 512
R_ALIGN = 512
STATUS = NF_ENDDEF(NCID, H_MINFREE, V_ALIGN, V_MINFREE, R_ALIGN)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
2.14 NF_CLOSE
=============
The function NF_CLOSE closes an open netCDF dataset. If the dataset is
in define mode, NF_ENDDEF will be called before closing. (In this case,
if NF_ENDDEF returns an error, NF_ABORT will automatically be called to
restore the dataset to the consistent state before define mode was last
entered.) After an open netCDF dataset is closed, its netCDF ID may be
reassigned to the next netCDF dataset that is opened or created.
Usage
=====
INTEGER FUNCTION NF_CLOSE(INTEGER NCID)
`NCID'
NetCDF ID, from a previous call to NF_OPEN or NF_CREATE.
Errors
======
NF_CLOSE returns the value NF_NOERR if no errors occurred. Otherwise,
the returned status indicates an error. Possible causes of errors
include:
* Define mode was entered and the automatic call made to NF_ENDDEF
failed.
* The specified netCDF ID does not refer to an open netCDF dataset.
Example
=======
Here is an example using NF_CLOSE to finish the definitions of a new
netCDF dataset named foo.nc and release its netCDF ID:
INCLUDE 'netcdf.inc'
...
INTEGER NCID, STATUS
...
STATUS = NF_CREATE('foo.nc', NF_NOCLOBBER, NCID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
... ! create dimensions, variables, attributes
STATUS = NF_CLOSE(NCID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
2.15 NF_INQ Family
==================
Members of the NF_INQ family of functions return information about an
open netCDF dataset, given its netCDF ID. Dataset inquire functions may
be called from either define mode or data mode. The first function,
NF_INQ, returns values for the number of dimensions, the number of
variables, the number of global attributes, and the dimension ID of the
dimension defined with unlimited length, if any. The other functions in
the family each return just one of these items of information.
For FORTRAN, these functions include NF_INQ, NF_INQ_NDIMS,
NF_INQ_NVARS, NF_INQ_NATTS, and NF_INQ_UNLIMDIM. An additional
function, NF_INQ_FORMAT, returns the (rarely needed) format version.
No I/O is performed when these functions are called, since the
required information is available in memory for each open netCDF
dataset.
Usage
=====
INTEGER FUNCTION NF_INQ (INTEGER NCID, INTEGER ndims,
INTEGER nvars,INTEGER ngatts,
INTEGER unlimdimid)
INTEGER FUNCTION NF_INQ_NDIMS (INTEGER NCID, INTEGER ndims)
INTEGER FUNCTION NF_INQ_NVARS (INTEGER NCID, INTEGER nvars)
INTEGER FUNCTION NF_INQ_NATTS (INTEGER NCID, INTEGER ngatts)
INTEGER FUNCTION NF_INQ_UNLIMDIM (INTEGER NCID, INTEGER unlimdimid)
INTEGER FUNCTION NF_INQ_FORMAT (INTEGER NCID, INTEGER format)
`NCID'
NetCDF ID, from a previous call to NF_OPEN or NF_CREATE.
`ndims'
Returned number of dimensions defined for this netCDF dataset.
`nvars'
Returned number of variables defined for this netCDF dataset.
`ngatts'
Returned number of global attributes defined for this netCDF
dataset.
`unlimdimid'
Returned ID of the unlimited dimension, if there is one for this
netCDF dataset. If no unlimited length dimension has been defined,
-1 is returned.
`format'
Returned format version, one of NF_FORMAT_CLASSIC,
NF_FORMAT_64BIT, NF_FORMAT_NETCDF4, NF_FORMAT_NETCDF4_CLASSIC.
Errors
======
All members of the NF_INQ family return the value NF_NOERR if no errors
occurred. Otherwise, the returned status indicates an error. Possible
causes of errors include:
* The specified netCDF ID does not refer to an open netCDF dataset.
Example
=======
Here is an example using NF_INQ to find out about a netCDF dataset
named foo.nc:
INCLUDE 'netcdf.inc'
...
INTEGER STATUS, NCID, NDIMS, NVARS, NGATTS, UNLIMDIMID
...
STATUS = NF_OPEN('foo.nc', NF_NOWRITE, NCID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
STATUS = NF_INQ(NCID, NDIMS, NVARS, NGATTS, UNLIMDIMID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
2.16 NF_SYNC
============
The function NF_SYNC offers a way to synchronize the disk copy of a
netCDF dataset with in-memory buffers. There are two reasons you might
want to synchronize after writes:
* To minimize data loss in case of abnormal termination, or
* To make data available to other processes for reading immediately
after it is written. But note that a process that already had the
dataset open for reading would not see the number of records
increase when the writing process calls NF_SYNC; to accomplish
this, the reading process must call NF_SYNC.
This function is backward-compatible with previous versions of the
netCDF library. The intent was to allow sharing of a netCDF dataset
among multiple readers and one writer, by having the writer call
NF_SYNC after writing and the readers call NF_SYNC before each read.
For a writer, this flushes buffers to disk. For a reader, it makes sure
that the next read will be from disk rather than from previously cached
buffers, so that the reader will see changes made by the writing
process (e.g., the number of records written) without having to close
and reopen the dataset. If you are only accessing a small amount of
data, it can be expensive in computer resources to always synchronize
to disk after every write, since you are giving up the benefits of
buffering.
An easier way to accomplish sharing (and what is now recommended) is
to have the writer and readers open the dataset with the NF_SHARE flag,
and then it will not be necessary to call NF_SYNC at all. However, the
NF_SYNC function still provides finer granularity than the NF_SHARE
flag, if only a few netCDF accesses need to be synchronized among
processes.
It is important to note that changes to the ancillary data, such as
attribute values, are not propagated automatically by use of the
NF_SHARE flag. Use of the NF_SYNC function is still required for this
purpose.
Sharing datasets when the writer enters define mode to change the
data schema requires extra care. In previous releases, after the writer
left define mode, the readers were left looking at an old copy of the
dataset, since the changes were made to a new copy. The only way
readers could see the changes was by closing and reopening the dataset.
Now the changes are made in place, but readers have no knowledge that
their internal tables are now inconsistent with the new dataset schema.
If netCDF datasets are shared across redefinition, some mechanism
external to the netCDF library must be provided that prevents access by
readers during redefinition and causes the readers to call NF_SYNC
before any subsequent access.
When calling NF_SYNC, the netCDF dataset must be in data mode. A
netCDF dataset in define mode is synchronized to disk only when
NF_ENDDEF is called. A process that is reading a netCDF dataset that
another process is writing may call NF_SYNC to get updated with the
changes made to the data by the writing process (e.g., the number of
records written), without having to close and reopen the dataset.
Data is automatically synchronized to disk when a netCDF dataset is
closed, or whenever you leave define mode.
Usage
=====
INTEGER FUNCTION NF_SYNC(INTEGER NCID)
`NCID'
NetCDF ID, from a previous call to NF_OPEN or NF_CREATE.
Errors
======
NF_SYNC returns the value NF_NOERR if no errors occurred. Otherwise,
the returned status indicates an error. Possible causes of errors
include:
* The netCDF dataset is in define mode.
* The specified netCDF ID does not refer to an open netCDF dataset.
Example
=======
Here is an example using NF_SYNC to synchronize the disk writes of a
netCDF dataset named foo.nc:
INCLUDE 'netcdf.inc'
...
INTEGER STATUS, NCID
...
STATUS = NF_OPEN('foo.nc', NF_WRITE, NCID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
! write data or change attributes
...
STATUS = NF_SYNC(NCID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
2.17 NF_ABORT
=============
You no longer need to call this function, since it is called
automatically by NF_CLOSE in case the dataset is in define mode and
something goes wrong with committing the changes. The function NF_ABORT
just closes the netCDF dataset, if not in define mode. If the dataset
is being created and is still in define mode, the dataset is deleted.
If define mode was entered by a call to NF_REDEF, the netCDF dataset is
restored to its state before definition mode was entered and the
dataset is closed.
Usage
=====
INTEGER FUNCTION NF_ABORT(INTEGER NCID)
`NCID'
NetCDF ID, from a previous call to NF_OPEN or NF_CREATE.
Errors
======
NF_ABORT returns the value NF_NOERR if no errors occurred. Otherwise,
the returned status indicates an error. Possible causes of errors
include:
* When called from define mode while creating a netCDF dataset,
deletion of the dataset failed.
* The specified netCDF ID does not refer to an open netCDF dataset.
Example
=======
Here is an example using NF_ABORT to back out of redefinitions of a
dataset named foo.nc:
INCLUDE 'netcdf.inc'
...
INTEGER STATUS, NCID, LATID
...
STATUS = NF_OPEN('foo.nc', NF_WRITE, NCID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
STATUS = NF_REDEF(NCID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
STATUS = NF_DEF_DIM(NCID, 'LAT', 18, LATID)
IF (STATUS .NE. NF_NOERR) THEN ! dimension definition failed
CALL HANDLE_ERR(STATUS)
STATUS = NF_ABORT(NCID) ! abort redefinitions
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
ENDIF
...
2.18 NF_SET_FILL
================
This function is intended for advanced usage, to optimize writes under
some circumstances described below. The function NF_SET_FILL sets the
fill mode for a netCDF dataset open for writing and returns the current
fill mode in a return parameter. The fill mode can be specified as
either NF_FILL or NF_NOFILL. The default behavior corresponding to
NF_FILL is that data is pre-filled with fill values, that is fill
values are written when you create non-record variables or when you
write a value beyond data that has not yet been written. This makes it
possible to detect attempts to read data before it was written. *Note
Fill Values::, for more information on the use of fill values. *Note
Attribute Conventions: (netcdf)Attribute Conventions, for information
about how to define your own fill values.
The behavior corresponding to NF_NOFILL overrides the default
behavior of prefilling data with fill values. This can be used to
enhance performance, because it avoids the duplicate writes that occur
when the netCDF library writes fill values that are later overwritten
with data.
A value indicating which mode the netCDF dataset was already in is
returned. You can use this value to temporarily change the fill mode of
an open netCDF dataset and then restore it to the previous mode.
After you turn on NF_NOFILL mode for an open netCDF dataset, you must
be certain to write valid data in all the positions that will later be
read. Note that nofill mode is only a transient property of a netCDF
dataset open for writing: if you close and reopen the dataset, it will
revert to the default behavior. You can also revert to the default
behavior by calling NF_SET_FILL again to explicitly set the fill mode
to NF_FILL.
There are three situations where it is advantageous to set nofill
mode:
1. Creating and initializing a netCDF dataset. In this case, you
should set nofill mode before calling NF_ENDDEF and then write
completely all non-record variables and the initial records of all
the record variables you want to initialize.
2. Extending an existing record-oriented netCDF dataset. Set nofill
mode after opening the dataset for writing, then append the
additional records to the dataset completely, leaving no
intervening unwritten records.
3. Adding new variables that you are going to initialize to an
existing netCDF dataset. Set nofill mode before calling NF_ENDDEF
then write all the new variables completely.
If the netCDF dataset has an unlimited dimension and the last record
was written while in nofill mode, then the dataset may be shorter than
if nofill mode was not set, but this will be completely transparent if
you access the data only through the netCDF interfaces.
The use of this feature may not be available (or even needed) in
future releases. Programmers are cautioned against heavy reliance upon
this feature.
Usage
=====
INTEGER FUNCTION NF_SET_FILL(INTEGER NCID, INTEGER FILLMODE,
INTEGER old_mode)
`NCID'
NetCDF ID, from a previous call to NF_OPEN or NF_CREATE.
`FILLMODE'
Desired fill mode for the dataset, either NF_NOFILL or NF_FILL.
`old_mode'
Returned current fill mode of the dataset before this call, either
NF_NOFILL or NF_FILL.
Errors
======
NF_SET_FILL returns the value NF_NOERR if no errors occurred.
Otherwise, the returned status indicates an error. Possible causes of
errors include:
* The specified netCDF ID does not refer to an open netCDF dataset.
* The specified netCDF ID refers to a dataset open for read-only
access.
* The fill mode argument is neither NF_NOFILL nor NF_FILL..
Example
=======
Here is an example using NF_SET_FILL to set nofill mode for subsequent
writes of a netCDF dataset named foo.nc:
INCLUDE 'netcdf.inc'
...
INTEGER NCID, STATUS, OMODE
...
STATUS = NF_OPEN('foo.nc', NF_WRITE, NCID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
! write data with default prefilling behavior
...
STATUS = NF_SET_FILL(NCID, NF_NOFILL, OMODE)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
! write data with no prefilling
...
2.19 NF_SET_DEFAULT_FORMAT
==========================
This function is intended for advanced users.
In version 3.6, netCDF introduced a new data format, the first change
in the underlying binary data format since the netCDF interface was
released. The new format, 64-bit offset format, was introduced to
greatly relax the limitations on creating very large files.
In version 4.0, another new binary format was introduced:
netCDF-4/HDF5.
Users are warned that creating files in the 64-bit offset format
makes them unreadable by the netCDF library prior to version 3.6.0, and
creating files in netcdf-4/HDF5 format makes them unreadable by the
netCDF library prior to version 4.0. For reasons of compatibility,
users should continue to create files in netCDF classic format.
Users who do want to use 64-bit offset or netCDF-4/HDF5 format files
can create them directory from NF_CREATE, using the proper cmode flag.
(*note NF_CREATE::).
The function NF_SET_DEFAULT_FORMAT allows the user to change the
format of the netCDF file to be created by future calls to NF_CREATE
without changing the cmode flag.
This allows the user to convert a program to use the new formats
without changing all calls the NF_CREATE.
Once the default format is set, all future created files will be in
the desired format.
Constants are provided in the netcdf.inc file to be used with this
function: nf_format_classic, nf_format_64bit, nf_format_netcdf4 and
nf_format_netcdf4_classic.
Usage
=====
INTEGER FUNCTION NF_SET_DEFAULT_FORMAT(INTEGER FORMAT, INTEGER OLD_FORMT)
`FORMAT'
Either nf_format_classic, nf_format_64bit, nf_format_netcdf4 or
nf_format_netcdf4_classic.
`OLD_FORMAT'
The default format at the time the function is called is returned
here.
Errors
======
The following error codes may be returned by this function:
* An NF_EINVAL error is returned if an invalid default format is
specified.
Example
=======
INCLUDE 'netcdf.inc'
...
INTEGER STATUS, OLD_FORMAT
...
STATUS = NF_SET_DEFAULT_FORMAT(nf_format_64bit, OLD_FORMAT)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
2.20 Set HDF5 Chunk Cache for Future File Opens/Creates: NF_SET_CHUNK_CACHE
===========================================================================
This function changes the chunk cache settings in the HDF5 library. The
settings apply for subsequent file opens/creates. This function does
not change the chunk cache settings of already open files.
This affects the per-file chunk cache which the HDF5 layer
maintains. The chunk cache size can be tuned for better performance.
For more information, see the documentation for the H5Pset_cache()
function in the HDF5 library at the HDF5 website:
`http://hdfgroup.org/HDF5/'.
Usage
=====
INTEGER NF_SET_CHUNK_CACHE(INTEGER SIZE, INTEGER NELEMS, INTEGER PREEMPTION);
`SIZE'
The total size of the raw data chunk cache in MegaBytes.
`NELEMS'
The number slots in the per-variable chunk cache (should be a
prime number larger than the number of chunks in the cache).
`PREEMPTION'
The preemtion value must be between 0 and 100 inclusive and
indicates how much chunks that have been fully read are favored for
preemption. A value of zero means fully read chunks are treated no
differently than other chunks (the preemption is strictly LRU)
while a value of 100 means fully read chunks are always preempted
before other chunks.
Return Codes
============
`NF_NOERR'
No error.
`NF_EINVAL'
Parameters size and nelems must be non-zero positive integers, and
preemption must be between zero and 100 (inclusive). An NF_EINVAL
will be returned otherwise.
2.21 Get the HDF5 Chunk Cache Settings for Future File Opens/Creates: NF_GET_CHUNK_CACHE
========================================================================================
This function gets the chunk cache settings for the HDF5 library. The
settings apply for subsequent file opens/creates.
This affects the per-file chunk cache which the HDF5 layer
maintains. The chunk cache size can be tuned for better performance.
For more information, see the documentation for the H5Pget_cache()
function in the HDF5 library at the HDF5 website:
`http://hdfgroup.org/HDF5/'.
Usage
=====
INTEGER NC_GET_CHUNK_CACHE(INTEGER SIZE, INTEGER NELEMS, INTEGER PREEMPTION);
`SIZE'
The total size of the raw data chunk cache will be put here.
`NELEMS'
The number of chunk slots in the raw data chunk cache hash table
will be put here.
`PREEMPTION'
The preemption will be put here. The preemtion value is between 0
and 100 inclusive and indicates how much chunks that have been
fully read are favored for preemption. A value of zero means
fully read chunks are treated no differently than other chunks
(the preemption is strictly LRU) while a value of 100 means fully
read chunks are always preempted before other chunks.
Return Codes
============
`NC_NOERR'
No error.
3 Groups
********
NetCDF-4 added support for hierarchical groups within netCDF datasets.
Groups are identified with a ncid, which identifies both the open
file, and the group within that file. When a file is opened with
NF_OPEN or NF_CREATE, the ncid for the root group of that file is
provided. Using that as a starting point, users can add new groups, or
list and navigate existing groups.
All netCDF calls take a ncid which determines where the call will
take its action. For example, the NF_DEF_VAR function takes a ncid as
its first parameter. It will create a variable in whichever group its
ncid refers to. Use the root ncid provided by NF_CREATE or NF_OPEN to
create a variable in the root group. Or use NF_DEF_GRP to create a
group and use its ncid to define a variable in the new group.
Variable are only visible in the group in which they are defined. The
same applies to attributes. "Global" attributes are defined in
whichever group is refered to by the ncid.
Dimensions are visible in their groups, and all child groups.
Group operations are only permitted on netCDF-4 files - that is,
files created with the HDF5 flag in nf_create. (*note NF_CREATE::).
Groups are not compatible with the netCDF classic data model, so files
created with the NF_CLASSIC_MODEL file cannot contain groups (except
the root group).
3.1 Find a Group ID: NF_INQ_NCID
================================
Given an ncid and group name (NULL or "" gets root group), return ncid
of the named group.
Usage
=====
INTEGER FUNCTION NF_INQ_NCID(INTEGER NCID, CHARACTER*(*) NAME, INTEGER GRPID)
`NCID'
The group id for this operation.
`NAME'
A character array that holds the name of the desired group. Must be
less then NF_MAX_NAME.
`GRPID'
The ID of the group will go here.
Errors
======
`NF_NOERR'
No error.
`NF_EBADID'
Bad group id.
`NF_ENOTNC4'
Attempting a netCDF-4 operation on a netCDF-3 file. NetCDF-4
operations can only be performed on files defined with a create
mode which includes flag HDF5. (*note NF_OPEN::).
`NF_ESTRICTNC3'
This file was created with the strict netcdf-3 flag, therefore
netcdf-4 operations are not allowed. (*note NF_OPEN::).
`NF_EHDFERR'
An error was reported by the HDF5 layer.
Example
=======
This example is from nf_test/ftst_groups.F.
C Check getting the group by name
retval = nf_inq_ncid(ncid, group_name, grpid_in)
if (retval .ne. nf_noerr) call handle_err(retval)
3.2 Get a List of Groups in a Group: NF_INQ_GRPS
================================================
Given a location id, return the number of groups it contains, and an
array of their ncids.
Usage
=====
INTEGER FUNCTION NF_INQ_GRPS(INTEGER NCID, INTEGER NUMGRPS, INTEGER NCIDS)
`NCID'
The group id for this operation.
`NUMGRPS'
An integer which will get number of groups in this group.
`NCIDS'
An array of ints which will receive the IDs of all the groups in
this group.
Errors
======
`NF_NOERR'
No error.
`NF_EBADID'
Bad group id.
`NF_ENOTNC4'
Attempting a netCDF-4 operation on a netCDF-3 file. NetCDF-4
operations can only be performed on files defined with a create
mode which includes flag HDF5. (*note NF_OPEN::).
`NF_ESTRICTNC3'
This file was created with the strict netcdf-3 flag, therefore
netcdf-4 operations are not allowed. (*note NF_OPEN::).
`NF_EHDFERR'
An error was reported by the HDF5 layer.
Example
=======
This example is from nf_test/ftst_groups.F.
C What groups are there from the root group?
retval = nf_inq_grps(ncid, ngroups_in, grpids)
if (retval .ne. nf_noerr) call handle_err(retval)
3.3 Find all the Variables in a Group: NF_INQ_VARIDS
====================================================
Find all varids for a location.
Usage
=====
INTEGER FUNCTION NF_INQ_VARIDS(INTEGER NCID, INTEGERS VARIDS)
`NCID'
The group id for this operation.
`VARIDS'
An already allocated array to store the list of varids. Use
nf_inq_nvars to find out how many variables there are. (*note
NF_INQ Family::).
Errors
======
`NF_NOERR'
No error.
`NF_EBADID'
Bad group id.
`NF_ENOTNC4'
Attempting a netCDF-4 operation on a netCDF-3 file. NetCDF-4
operations can only be performed on files defined with a create
mode which includes flag HDF5. (*note NF_OPEN::).
`NF_ESTRICTNC3'
This file was created with the strict netcdf-3 flag, therefore
netcdf-4 operations are not allowed. (*note NF_OPEN::).
`NF_EHDFERR'
An error was reported by the HDF5 layer.
Example
=======
This example is from nf_test/ftst_groups.F.
C Check varids in subgroup.
retval = nf_inq_varids(subgrp_in, nvars, varids_in)
if (retval .ne. nf_noerr) call handle_err(retval)
3.4 Find all Dimensions Visible in a Group: NF_INQ_DIMIDS
=========================================================
Find all dimids for a location. This finds all dimensions in a group,
or any of its parents.
Usage
=====
INTEGER FUNCTION NF_INQ_DIMIDS(INTEGER NCID, INTEGER DIMIDS, INTEGER INCLUDE_PARENTS)
`NCID'
The group id for this operation.
`DIMIDS'
An array of ints when the dimids of the visible dimensions will be
stashed. Use nf_inq_ndims to find out how many dims are visible
from this group. (*note NF_INQ Family::).
`INCLUDE_PARENTS'
If zero, only the group specified by NCID will be searched for
dimensions. Otherwise parent groups will be searched too.
Errors
======
`NF_NOERR'
No error.
`NF_EBADID'
Bad group id.
`NF_ENOTNC4'
Attempting a netCDF-4 operation on a netCDF-3 file. NetCDF-4
operations can only be performed on files defined with a create
mode which includes flag HDF5. (*note NF_OPEN::).
`NF_ESTRICTNC3'
This file was created with the strict netcdf-3 flag, therefore
netcdf-4 operations are not allowed. (*note NF_OPEN::).
`NF_EHDFERR'
An error was reported by the HDF5 layer.
Example
=======
This example is from nf_test/ftst_groups.F.
C Check dimids in subgroup.
retval = nf_inq_dimids(subgrp_in, ndims, dimids_in, 0)
if (retval .ne. nf_noerr) call handle_err(retval)
if (ndims .ne. 2 .or. dimids_in(1) .ne. dimids(1) .or.
& dimids_in(2) .ne. dimids(2)) stop 2
3.5 Find the Length of a Group's Name: NF_INQ_GRPNAME_LEN
=========================================================
Given ncid, find length of the full name. (Root group is named "/",
with length 1.)
Usage
=====
INTEGER FUNCTION NF_INQ_GRPNAME_LEN(INTEGER NCID, INTEGER LEN)
`NCID'
The group id for this operation.
`LEN'
An integer where the length will be placed.
Errors
======
`NF_NOERR'
No error.
`NF_EBADID'
Bad group id.
`NF_ENOTNC4'
Attempting a netCDF-4 operation on a netCDF-3 file. NetCDF-4
operations can only be performed on files defined with a create
mode which includes flag HDF5. (*note NF_OPEN::).
`NF_ESTRICTNC3'
This file was created with the strict netcdf-3 flag, therefore
netcdf-4 operations are not allowed. (*note NF_OPEN::).
`NF_EHDFERR'
An error was reported by the HDF5 layer.
Example
=======
This example is from nf_test/ftst_groups.F.
C Check the length of the full name.
retval = nf_inq_grpname_len(grpids(1), full_name_len)
if (retval .ne. nf_noerr) call handle_err(retval)
3.6 Find a Group's Name: NF_INQ_GRPNAME
=======================================
Given ncid, find relative name of group. (Root group is named "/").
The name provided by this function is relative to the parent group.
For a full path name for the group is, with all parent groups included,
separated with a forward slash (as in Unix directory names) *Note
NF_INQ_GRPNAME_FULL::.
Usage
=====
INTEGER FUNCTION NF_INQ_GRPNAME(INTEGER NCID, CHARACTER*(*) NAME)
`NCID'
The group id for this operation.
`NAME'
The name of the group will be copied to this character array. The
name will be less than NF_MAX_NAME in length.
`'
Errors
======
`NF_NOERR'
No error.
`NF_EBADID'
Bad group id.
`NF_ENOTNC4'
Attempting a netCDF-4 operation on a netCDF-3 file. NetCDF-4
operations can only be performed on files defined with a create
mode which includes flag HDF5. (*note NF_OPEN::).
`NF_ESTRICTNC3'
This file was created with the strict netcdf-3 flag, therefore
netcdf-4 operations are not allowed. (*note NF_OPEN::).
`NF_EHDFERR'
An error was reported by the HDF5 layer.
Example
=======
This example is from nf_test/ftst_groups.F.
C Check the name of the root group.
retval = nf_inq_grpname(ncid, name_in)
if (retval .ne. nf_noerr) call handle_err(retval)
if (name_in(1:1) .ne. '/') stop 2
3.7 Find a Group's Full Name: NF_INQ_GRPNAME_FULL
=================================================
Given ncid, find complete name of group. (Root group is named "/").
The name provided by this function is a full path name for the group
is, with all parent groups included, separated with a forward slash (as
in Unix directory names). For a name relative to the parent group *Note
NF_INQ_GRPNAME::.
To find the length of the full name *Note NF_INQ_GRPNAME_LEN::.
Usage
=====
INTEGER FUNCTION NF_INQ_GRPNAME_FULL(INTEGER NCID, INTEGER LEN, CHARACTER*(*) NAME)
`NCID'
The group id for this operation.
`LEN'
The length of the full group name will go here.
`NAME'
The name of the group will be copied to this character array.
Errors
======
`NF_NOERR'
No error.
`NF_EBADID'
Bad group id.
`NF_ENOTNC4'
Attempting a netCDF-4 operation on a netCDF-3 file. NetCDF-4
operations can only be performed on files defined with a create
mode which includes flag HDF5. (*note NF_OPEN::).
`NF_ESTRICTNC3'
This file was created with the strict netcdf-3 flag, therefore
netcdf-4 operations are not allowed. (*note NF_OPEN::).
`NF_EHDFERR'
An error was reported by the HDF5 layer.
Example
=======
This example is from nf_test/ftst_groups.F.
C Check the full name.
retval = nf_inq_grpname_full(grpids(1), full_name_len, name_in2)
if (retval .ne. nf_noerr) call handle_err(retval)
3.8 Find a Group's Parent: NF_INQ_GRP_PARENT
============================================
Given ncid, find the ncid of the parent group.
When used with the root group, this function returns the NF_ENOGRP
error (since the root group has no parent.)
Usage
=====
INTEGER FUNCTION NF_INQ_GRP_PARENT(INTEGER NCID, INTEGER PARENT_NCID)
`NCID'
The group id.
`PARENT_NCID'
The ncid of the parent group will be copied here.
Errors
======
`NF_NOERR'
No error.
`NF_EBADID'
Bad group id.
`NF_ENOGRP'
No parent group found (i.e. this is the root group).
`NF_ENOTNC4'
Attempting a netCDF-4 operation on a netCDF-3 file. NetCDF-4
operations can only be performed on files defined with a create
mode which includes flag HDF5. (*note NF_OPEN::).
`NF_ESTRICTNC3'
This file was created with the strict netcdf-3 flag, therefore
netcdf-4 operations are not allowed. (*note NF_OPEN::).
`NF_EHDFERR'
An error was reported by the HDF5 layer.
Example
=======
This example is from nf_test/ftst_groups.F.
C Check the parent ncid.
retval = nf_inq_grp_parent(grpids(1), grpid_in)
if (retval .ne. nf_noerr) call handle_err(retval)
3.9 Find a Group by Name: NF_INQ_GRP_NCID
=========================================
Given a group name an an ncid, find the ncid of the group id.
Usage
=====
INTEGER FUNCTION NF_INQ_GRP_NCID(INTEGER NCID, CHARACTER GRP_NAME, INTEGER GRP_NCID)
`NCID'
The group id to look in.
`GRP_NAME'
The name of the group that should be found.
`GRP_NCID'
This will get the group id, if it is found.
Return Codes
============
The following return codes may be returned by this function.
`NF_NOERR'
No error.
`NF_EBADID'
Bad group id.
`NF_EINVAL'
No name provided or name longer than NF_MAX_NAME.
`NF_ENOGRP'
Named group not found.
`NF_ENOTNC4'
Attempting a netCDF-4 operation on a netCDF-3 file. NetCDF-4
operations can only be performed on files defined with a create
mode which includes flag HDF5. (*note NF_OPEN::).
`NF_ESTRICTNC3'
This file was created with the strict netcdf-3 flag, therefore
netcdf-4 operations are not allowed. (*note NF_OPEN::).
`NF_EHDFERR'
An error was reported by the HDF5 layer.
Example
=======
This example is from nf_test/ftst_types3.F.
C Go to a child group and find the id of our type.
retval = nf_inq_grp_ncid(ncid, group_name, sub_grpid)
if (retval .ne. nf_noerr) call handle_err(retval)
3.10 Find a Group by its Fully-qualified Name: NF_INQ_GRP_FULL_NCID
===================================================================
Given a fully qualified group name an an ncid, find the ncid of the
group id.
Usage
=====
INTEGER FUNCTION NF_INQ_GRP_FULL_NCID(INTEGER NCID, CHARACTER FULL_NAME, INTEGER GRP_NCID)
`NCID'
The group id to look in.
`FULL_NAME'
The fully-qualified group name.
`GRP_NCID'
This will get the group id, if it is found.
Return Codes
============
The following return codes may be returned by this function.
`NF_NOERR'
No error.
`NF_EBADID'
Bad group id.
`NF_EINVAL'
No name provided or name longer than NF_MAX_NAME.
`NF_ENOGRP'
Named group not found.
`NF_ENOTNC4'
Attempting a netCDF-4 operation on a netCDF-3 file. NetCDF-4
operations can only be performed on files defined with a create
mode which includes flag HDF5. (*note NF_OPEN::).
`NF_ESTRICTNC3'
This file was created with the strict netcdf-3 flag, therefore
netcdf-4 operations are not allowed. (*note NF_OPEN::).
`NF_EHDFERR'
An error was reported by the HDF5 layer.
Example
=======
This example is from nf_test/ftst_groups.F.
C Check the full name of the root group (also "/").
retval = nf_inq_grpname_full(ncid, full_name_len, name_in)
if (retval .ne. nf_noerr) call handle_err(retval)
3.11 Create a New Group: NF_DEF_GRP
===================================
Create a group. Its location id is returned in new_ncid.
Usage
=====
INTEGER FUNCTION NF_DEF_GRP(INTEGER PARENT_NCID, CHARACTER*(*) NAME,
INTEGER NEW_NCID)
`PARENT_NCID'
The group id of the parent group.
`NAME'
The name of the new group.
`NEW_NCID'
The ncid of the new group will be placed there.
Errors
======
`NF_NOERR'
No error.
`NF_EBADID'
Bad group id.
`NF_ENAMEINUSE'
That name is in use. Group names must be unique within a group.
`NF_EMAXNAME'
Name exceed max length NF_MAX_NAME.
`NF_EBADNAME'
Name contains illegal characters.
`NF_ENOTNC4'
Attempting a netCDF-4 operation on a netCDF-3 file. NetCDF-4
operations can only be performed on files defined with a create
mode which includes flag HDF5. (*note NF_OPEN::).
`NF_ESTRICTNC3'
This file was created with the strict netcdf-3 flag, therefore
netcdf-4 operations are not allowed. (*note NF_OPEN::).
`NF_EHDFERR'
An error was reported by the HDF5 layer.
`NF_EPERM'
Attempt to write to a read-only file.
`NF_ENOTINDEFINE'
Not in define mode.
Example
=======
In this exampe rom nf_test/ftst_groups.F, a groups is reated, and then
a sub-group is created in that group.
C Create the netCDF file.
retval = nf_create(file_name, NF_NETCDF4, ncid)
if (retval .ne. nf_noerr) call handle_err(retval)
C Create a group and a subgroup.
retval = nf_def_grp(ncid, group_name, grpid)
if (retval .ne. nf_noerr) call handle_err(retval)
retval = nf_def_grp(grpid, sub_group_name, sub_grpid)
if (retval .ne. nf_noerr) call handle_err(retval)
4 Dimensions
************
4.1 Dimensions Introduction
===========================
Dimensions for a netCDF dataset are defined when it is created, while
the netCDF dataset is in define mode. Additional dimensions may be
added later by reentering define mode. A netCDF dimension has a name
and a length. At most one dimension in a netCDF dataset can have the
unlimited length, which means variables using this dimension can grow
along this dimension.
There is a suggested limit (100) to the number of dimensions that can
be defined in a single netCDF dataset. The limit is the value of the
predefined macro NF_MAX_DIMS. The purpose of the limit is to make
writing generic applications simpler. They need only provide an array
of NF_MAX_DIMS dimensions to handle any netCDF dataset. The
implementation of the netCDF library does not enforce this advisory
maximum, so it is possible to use more dimensions, if necessary, but
netCDF utilities that assume the advisory maximums may not be able to
handle the resulting netCDF datasets.
Ordinarily, the name and length of a dimension are fixed when the
dimension is first defined. The name may be changed later, but the
length of a dimension (other than the unlimited dimension) cannot be
changed without copying all the data to a new netCDF dataset with a
redefined dimension length.
A netCDF dimension in an open netCDF dataset is referred to by a
small integer called a dimension ID. In the FORTRAN interface,
dimension IDs are 1, 2, 3, ..., in the order in which the dimensions
were defined.
Operations supported on dimensions are:
* Create a dimension, given its name and length.
* Get a dimension ID from its name.
* Get a dimension's name and length from its ID.
* Rename a dimension.
4.2 NF_DEF_DIM
==============
The function NF_DEF_DIM adds a new dimension to an open netCDF dataset
in define mode. It returns (as an argument) a dimension ID, given the
netCDF ID, the dimension name, and the dimension length. At most one
unlimited length dimension, called the record dimension, may be defined
for each netCDF dataset.
Usage
=====
INTEGER FUNCTION NF_DEF_DIM (INTEGER NCID, CHARACTER*(*) NAME,
INTEGER LEN, INTEGER dimid)
`NCID'
NetCDF ID, from a previous call to NF_OPEN or NF_CREATE.
`NAME'
Dimension name.
`LEN'
Length of dimension; that is, number of values for this dimension
as an index to variables that use it. This should be either a
positive integer or the predefined constant NF_UNLIMITED.
`dimid'
Returned dimension ID.
Errors
======
NF_DEF_DIM returns the value NF_NOERR if no errors occurred. Otherwise,
the returned status indicates an error. Possible causes of errors
include:
* The netCDF dataset is not in definition mode.
* The specified dimension name is the name of another existing
dimension.
* The specified length is not greater than zero.
* The specified length is unlimited, but there is already an
unlimited length dimension defined for this netCDF dataset.
* The specified netCDF ID does not refer to an open netCDF dataset.
Example
=======
Here is an example using NF_DEF_DIM to create a dimension named lat of
length 18 and a unlimited dimension named rec in a new netCDF dataset
named foo.nc:
INCLUDE 'netcdf.inc'
...
INTEGER STATUS, NCID, LATID, RECID
...
STATUS = NF_CREATE('foo.nc', NF_NOCLOBBER, NCID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
STATUS = NF_DEF_DIM(NCID, 'lat', 18, LATID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
STATUS = NF_DEF_DIM(NCID, 'rec', NF_UNLIMITED, RECID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
4.3 NF_INQ_DIMID
================
The function NF_INQ_DIMID returns (as an argument) the ID of a netCDF
dimension, given the name of the dimension. If ndims is the number of
dimensions defined for a netCDF dataset, each dimension has an ID
between 1 and ndims.
Usage
=====
INTEGER FUNCTION NF_INQ_DIMID (INTEGER NCID, CHARACTER*(*) NAME,
INTEGER dimid)
`NCID'
NetCDF ID, from a previous call to NF_OPEN or NF_CREATE.
`NAME'
Dimension name.
`dimid'
Returned dimension ID.
Errors
======
NF_INQ_DIMID returns the value NF_NOERR if no errors occurred.
Otherwise, the returned status indicates an error. Possible causes of
errors include:
* The name that was specified is not the name of a dimension in the
netCDF dataset.
* The specified netCDF ID does not refer to an open netCDF dataset.
Example
=======
Here is an example using NF_INQ_DIMID to determine the dimension ID of
a dimension named lat, assumed to have been defined previously in an
existing netCDF dataset named foo.nc:
INCLUDE 'netcdf.inc'
...
INTEGER STATUS, NCID, LATID
...
STATUS = NF_OPEN('foo.nc', NF_NOWRITE, NCID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
STATUS = NF_INQ_DIMID(NCID, 'lat', LATID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
4.4 NF_INQ_DIM Family
=====================
This family of functions returns information about a netCDF dimension.
Information about a dimension includes its name and its length. The
length for the unlimited dimension, if any, is the number of records
written so far.
The functions in this family include NF_INQ_DIM, NF_INQ_DIMNAME, and
NF_INQ_DIMLEN. The function NF_INQ_DIM returns all the information
about a dimension; the other functions each return just one item of
information.
Usage
=====
INTEGER FUNCTION NF_INQ_DIM (INTEGER NCID, INTEGER DIMID,
CHARACTER*(*) name, INTEGER len)
INTEGER FUNCTION NF_INQ_DIMNAME (INTEGER NCID, INTEGER DIMID,
CHARACTER*(*) name)
INTEGER FUNCTION NF_INQ_DIMLEN (INTEGER NCID, INTEGER DIMID,
INTEGER len)
`NCID'
NetCDF ID, from a previous call to NF_OPEN or NF_CREATE.
`DIMID'
Dimension ID, from a previous call to NF_INQ_DIMID or NF_DEF_DIM.
`NAME'
Returned dimension name. The caller must allocate space for the
returned name. The maximum possible length, in characters, of a
dimension name is given by the predefined constant NF_MAX_NAME.
`len'
Returned length of dimension. For the unlimited dimension, this is
the current maximum value used for writing any variables with this
dimension, that is the maximum record number.
Errors
======
These functions return the value NF_NOERR if no errors occurred.
Otherwise, the returned status indicates an error. Possible causes of
errors include:
* The dimension ID is invalid for the specified netCDF dataset.
* The specified netCDF ID does not refer to an open netCDF dataset.
Example
=======
Here is an example using NF_INQ_DIM to determine the length of a
dimension named lat, and the name and current maximum length of the
unlimited dimension for an existing netCDF dataset named foo.nc:
INCLUDE 'netcdf.inc'
...
INTEGER STATUS, NCID, LATID, LATLEN, RECID, NRECS
CHARACTER*(NF_MAX_NAME) LATNAM, RECNAM
...
STATUS = NF_OPEN('foo.nc', NF_NOWRITE, NCID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
! get ID of unlimited dimension
STATUS = NF_INQ_UNLIMDIM(NCID, RECID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
STATUS = NF_INQ_DIMID(NCID, 'lat', LATID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
! get lat length
STATUS = NF_INQ_DIMLEN(NCID, LATID, LATLEN)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
! get unlimited dimension name and current length
STATUS = NF_INQ_DIM(NCID, RECID, RECNAME, NRECS)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
4.5 NF_RENAME_DIM
=================
The function NF_RENAME_DIM renames an existing dimension in a netCDF
dataset open for writing. If the new name is longer than the old name,
the netCDF dataset must be in define mode. You cannot rename a
dimension to have the same name as another dimension.
Usage
=====
INTEGER FUNCTION NF_RENAME_DIM (INTEGER NCID, INTEGER DIMID,
CHARACTER*(*) NAME)
`NCID'
NetCDF ID, from a previous call to NF_OPEN or NF_CREATE.
`DIMID'
Dimension ID, from a previous call to NF_INQ_DIMID or NF_DEF_DIM.
`NAME'
New dimension name.
Errors
======
NF_RENAME_DIM returns the value NF_NOERR if no errors occurred.
Otherwise, the returned status indicates an error. Possible causes of
errors include:
* The new name is the name of another dimension.
* The dimension ID is invalid for the specified netCDF dataset.
* The specified netCDF ID does not refer to an open netCDF dataset.
* The new name is longer than the old name and the netCDF dataset is
not in define mode.
Example
=======
Here is an example using NF_RENAME_DIM to rename the dimension lat to
latitude in an existing netCDF dataset named foo.nc:
INCLUDE 'netcdf.inc'
...
INTEGER STATUS, NCID, LATID
...
STATUS = NF_OPEN('foo.nc', NF_WRITE, NCID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
! put in define mode to rename dimension
STATUS = NF_REDEF(NCID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
STATUS = NF_INQ_DIMID(NCID, 'lat', LATID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
STATUS = NF_RENAME_DIM(NCID, LATID, 'latitude')
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
! leave define mode
STATUS = NF_ENDDEF(NCID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
5 User Defined Data Types
*************************
5.1 User Defined Types Introduction
===================================
NetCDF-4 has added support for four different user defined data types.
`compound type'
Like a C struct, a compound type is a collection of types,
including other user defined types, in one package.
`variable length array type'
The variable length array may be used to store ragged arrays.
`opaque type'
This type has only a size per element, and no other type
information.
`enum type'
Like an enumeration in C, this type lets you assign text values to
integer values, and store the integer values.
Users may construct user defined type with the various NF_DEF_*
functions described in this section. They may learn about user defined
types by using the NF_INQ_ functions defined in this section.
Once types are constructed, define variables of the new type with
NF_DEF_VAR (*note NF_DEF_VAR::). Write to them with NF_PUT_VAR1,
NF_PUT_VAR, NF_PUT_VARA, or NF_PUT_VARS (*note Variables::). Read data
of user-defined type with NF_GET_VAR1, NF_GET_VAR, NF_GET_VARA, or
NF_GET_VARS (*note Variables::).
Create attributes of the new type with NF_PUT_ATT (*note NF_PUT_ATT_
type::). Read attributes of the new type with NF_GET_ATT (*note
NF_GET_ATT_ type::).
5.2 Learn the IDs of All Types in Group: NF_INQ_TYPEIDS
=======================================================
Learn the number of types defined in a group, and their IDs.
Usage
=====
INTEGER FUNCTION NF_INQ_TYPEIDS(INTEGER NCID, INTEGER NTYPES,
INTEGER TYPEIDS)
`NCID'
The group id.
`NTYPES'
A pointer to int which will get the number of types defined in the
group. If NULL, ignored.
`TYPEIDS'
A pointer to an int array which will get the typeids. If NULL,
ignored.
Errors
======
`NF_NOERR'
No error.
`NF_BADID'
Bad ncid.
Example
=======
The following example is from the test program nf_test/ftst_vars3.F.
retval = nf_inq_typeids(ncid, num_types, typeids)
if (retval .ne. nf_noerr) call handle_err(retval)
5.3 Find a Typeid from Group and Name: NF_INQ_TYPEID
====================================================
Given a group ID and a type name, find the ID of the type. If the type
is not found in the group, then the parents are searched. If still not
found, the entire file is searched.
Usage
=====
INTEGER FUNCTION NF_INQ_TYPEID(INTEGER NCID, CHARACTER NAME, NF_TYPE TYPEIDP)
`NCID'
The group id.
`NAME'
The name of a type.
`TYPEIDP'
The typeid of the named type (if found).
Errors
======
`NF_NOERR'
No error.
`NF_EBADID'
Bad ncid.
`NF_EBADTYPE'
Can't find type.
Example
=======
The following example is from nf_test/ftst_types3.F:
C Go to a child group and find the id of our type.
retval = nf_inq_grp_ncid(ncid, group_name, sub_grpid)
if (retval .ne. nf_noerr) call handle_err(retval)
retval = nf_inq_typeid(sub_grpid, type_name, typeid_in)
if (retval .ne. nf_noerr) call handle_err(retval)
5.4 Learn About a User Defined Type: NF_INQ_TYPE
================================================
Given an ncid and a typeid, get the information about a type. This
function will work on any type, including atomic and any user defined
type, whether compound, opaque, enumeration, or variable length array.
For even more information about a user defined type *note
NF_INQ_USER_TYPE::.
Usage
=====
INTEGER FUNCTION NF_INQ_TYPE(INTEGER NCID, INTEGER XTYPE,
CHARACTER*(*) NAME, INTEGER SIZE)
`NCID'
The ncid for the group containing the type (ignored for atomic
types).
`XTYPE'
The typeid for this type, as returned by NF_DEF_COMPOUND,
NF_DEF_OPAQUE, NF_DEF_ENUM, NF_DEF_VLEN, or NF_INQ_VAR, or as
found in netcdf.inc in the list of atomic types (NF_CHAR, NF_INT,
etc.).
`NAME'
The name of the user defined type will be copied here. It will be
NF_MAX_NAME bytes or less. For atomic types, the type name from CDL
will be given.
`SIZEP'
The (in-memory) size of the type (in bytes) will be copied here.
VLEN type size is the size of one vlen sturture (i.e. the sice of
nc_vlen_t). String size is returned as the size of one C character
pointer.
Return Codes
============
`NF_NOERR'
No error.
`NF_EBADTYPEID'
Bad typeid.
`NF_ENOTNC4'
Seeking a user-defined type in a netCDF-3 file.
`NF_ESTRICTNC3'
Seeking a user-defined type in a netCDF-4 file for which classic
model has been turned on.
`NF_EBADGRPID'
Bad group ID in ncid.
`NF_EBADID'
Type ID not found.
`NF_EHDFERR'
An error was reported by the HDF5 layer.
Example
=======
This example is from the test program nf_test/ftst_vars3.F, and it uses
all the possible inquiry functions on an enum type.
C Check the enum type.
retval = NF_INQ_TYPEIDS(ncid, num_types, typeids)
if (retval .ne. nf_noerr) call handle_err(retval)
if (num_types .ne. MAX_TYPES) stop 2
retval = nf_inq_enum(ncid, typeids(1), type_name, base_type,
& base_size, num_members)
if (retval .ne. nf_noerr) call handle_err(retval)
if (base_type .ne. NF_INT .or. num_members .ne. 2) stop 2
retval = nf_inq_enum_member(ncid, typeids(1), 1, member_name,
& member_value)
if (retval .ne. nf_noerr) call handle_err(retval)
if (member_name(1:len(one_name)) .ne. one_name) stop 2
5.5 Learn About a User Defined Type: NF_INQ_USER_TYPE
=====================================================
Given an ncid and a typeid, get the information about a user defined
type. This function will work on any user defined type, whether
compound, opaque, enumeration, or variable length array.
Usage
=====
INTEGER FUNCTION NF_INQ_USER_TYPE(INTEGER NCID, INTEGER XTYPE,
CHARACTER*(*) NAME, INTEGER SIZE, INTEGER BASE_NF_TYPE,
INTEGER NFIELDS, INTEGER CLASS)
`NCID'
The ncid for the group containing the user defined type.
`XTYPE'
The typeid for this type, as returned by NF_DEF_COMPOUND,
NF_DEF_OPAQUE, NF_DEF_ENUM, NF_DEF_VLEN, or NF_INQ_VAR.
`NAME'
The name of the user defined type will be copied here. It will be
NF_MAX_NAME bytes or less.
`SIZE'
The (in-memory) size of the user defined type will be copied here.
`BASE_NF_TYPE'
The base typeid will be copied here for vlen and enum types.
`NFIELDS'
The number of fields will be copied here for enum and compound
types.
`CLASS'
The class of the user defined type, NF_VLEN, NF_OPAQUE, NF_ENUM, or
NF_COMPOUND, will be copied here.
Errors
======
`NF_NOERR'
No error.
`NF_EBADTYPEID'
Bad typeid.
`NF_EBADFIELDID'
Bad fieldid.
`NF_EHDFERR'
An error was reported by the HDF5 layer.
Example
=======
This example is from nf_test/ftst_types2.F.
C Check the type.
retval = nf_inq_user_type(ncid, typeids(1), name_in, size_in,
& base_type_in, nfields_in, class_in)
if (retval .ne. nf_noerr) call handle_err(retval)
5.6 Compound Types Introduction
===============================
NetCDF-4 added support for compound types, which allow users to
construct a new type - a combination of other types, like a C struct.
Compound types are not supported in classic or 64-bit offset format
files.
To write data in a compound type, first use nf_def_compound to
create the type, multiple calls to nf_insert_compound to add to the
compound type, and then write data with the appropriate nf_put_var1,
nf_put_vara, nf_put_vars, or nf_put_varm call.
To read data written in a compound type, you must know its
structure. Use the NF_INQ_COMPOUND functions to learn about the compound
type.
In Fortran a character buffer must be used for the compound data. The
user must read the data from within that buffer in the same way that
the C compiler which compiled netCDF would store the structure.
The use of compound types introduces challenges and portability
issues for Fortran users.
5.6.1 Creating a Compound Type: NF_DEF_COMPOUND
-----------------------------------------------
Create a compound type. Provide an ncid, a name, and a total size (in
bytes) of one element of the completed compound type.
After calling this function, fill out the type with repeated calls to
NF_INSERT_COMPOUND (*note NF_INSERT_COMPOUND::). Call
NF_INSERT_COMPOUND once for each field you wish to insert into the
compound type.
Note that there does not seem to be a way to read such types into
structures in Fortran 90 (and there are no structures in Fortran 77).
Fortran users may use character buffers to read and write compound
types.
Usage
=====
INTEGER FUNCTION NF_DEF_COMPOUND(INTEGER NCID, INTEGER SIZE,
CHARACTER*(*) NAME, INTEGER TYPEIDP)
`NCID'
The groupid where this compound type will be created.
`SIZE'
The size, in bytes, of the compound type.
`NAME'
The name of the new compound type.
`TYPEIDP'
The typeid of the new type will be placed here.
Errors
======
`NF_NOERR'
No error.
`NF_EBADID'
Bad group id.
`NF_ENAMEINUSE'
That name is in use. Compound type names must be unique in the data
file.
`NF_EMAXNAME'
Name exceeds max length NF_MAX_NAME.
`NF_EBADNAME'
Name contains illegal characters.
`NF_ENOTNC4'
Attempting a netCDF-4 operation on a netCDF-3 file. NetCDF-4
operations can only be performed on files defined with a create
mode which includes flag NF_NETCDF4. (*note NF_OPEN::).
`NF_ESTRICTNC3'
This file was created with the strict netcdf-3 flag, therefore
netcdf-4 operations are not allowed. (*note NF_OPEN::).
`NF_EHDFERR'
An error was reported by the HDF5 layer.
`NF_EPERM'
Attempt to write to a read-only file.
`NF_ENOTINDEFINE'
Not in define mode.
Example
=======
This example is from nf_test/ftst_types2.F.
C Define a compound type.
retval = nf_def_compound(ncid, cmp_size, type_name,
& cmp_typeid)
if (retval .ne. nf_noerr) call handle_err(retval)
5.6.2 Inserting a Field into a Compound Type: NF_INSERT_COMPOUND
----------------------------------------------------------------
Insert a named field into a compound type.
Usage
=====
INTEGER FUNTION NF_INSERT_COMPOUND(INTEGER TYPEID, CHARACTER*(*) NAME, INTEGER OFFSET,
INTEGER FIELD_TYPEID)
`TYPEID'
The typeid for this compound type, as returned by NF_DEF_COMPOUND,
or NF_INQ_VAR.
`NAME'
The name of the new field.
`OFFSET'
Offset in byte from the beginning of the compound type for this
field.
`FIELD_TYPEID'
The type of the field to be inserted.
Errors
======
`NF_NOERR'
No error.
`NF_EBADID'
Bad group id.
`NF_ENAMEINUSE'
That name is in use. Field names must be unique within a compound
type.
`NF_EMAXNAME'
Name exceed max length NF_MAX_NAME.
`NF_EBADNAME'
Name contains illegal characters.
`NF_ENOTNC4'
Attempting a netCDF-4 operation on a netCDF-3 file. NetCDF-4
operations can only be performed on files defined with a create
mode which includes flag NF_NETCDF4. (*note NF_OPEN::).
`NF_ESTRICTNC3'
This file was created with the strict netcdf-3 flag, therefore
netcdf-4 operations are not allowed. (*note NF_OPEN::).
`NF_EHDFERR'
An error was reported by the HDF5 layer.
`NF_ENOTINDEFINE'
Not in define mode.
Example
=======
This example is from nf_test/ftst_types.F.
C Define a compound type.
retval = nf_def_compound(ncid, WIND_T_SIZE, type_name,
& wind_typeid)
if (retval .ne. nf_noerr) call handle_err(retval)
retval = nf_insert_compound(ncid, wind_typeid, u_name, 0, NF_INT)
if (retval .ne. nf_noerr) call handle_err(retval)
retval = nf_insert_compound(ncid, wind_typeid, v_name, 4, NF_INT)
if (retval .ne. nf_noerr) call handle_err(retval)
5.6.3 Inserting an Array Field into a Compound Type: NF_INSERT_ARRAY_COMPOUND
-----------------------------------------------------------------------------
Insert a named array field into a compound type.
Usage
=====
INTEGER FUNCTION NF_INSERT_ARRAY_COMPOUND(INTEGER NCID, INTEGER XTYPE,
CHARACTER*(*) NAME, INTEGER OFFSET, INTEGER FIELD_TYPEID,
INTEGER NDIMS, INTEGER DIM_SIZES)
`NCID'
The ID of the file that contains the array type and the compound
type.
`XTYPE'
The typeid for this compound type, as returned by nf_def_compound,
or nf_inq_var.
`NAME'
The name of the new field.
`OFFSET'
Offset in byte from the beginning of the compound type for this
field.
`FIELD_TYPEID'
The base type of the array to be inserted.
`NDIMS'
The number of dimensions for the array to be inserted.
`DIM_SIZES'
An array containing the sizes of each dimension.
Errors
======
`NF_NOERR'
No error.
`NF_EBADID'
Bad group id.
`NF_ENAMEINUSE'
That name is in use. Field names must be unique within a compound
type.
`NF_EMAXNAME'
Name exceed max length NF_MAX_NAME.
`NF_EBADNAME'
Name contains illegal characters.
`NF_ENOTNC4'
Attempting a netCDF-4 operation on a netCDF-3 file. NetCDF-4
operations can only be performed on files defined with a create
mode which includes flag NF_NETCDF4. (*note NF_OPEN::).
`NF_ESTRICTNC3'
This file was created with the strict netcdf-3 flag, therefore
netcdf-4 operations are not allowed. (*note NF_OPEN::).
`NF_EHDFERR'
An error was reported by the HDF5 layer.
`NF_ENOTINDEFINE'
Not in define mode.
`NF_ETYPEDEFINED'
Attempt to change type that has already been committed. The first
time the file leaves define mode, all defined types are committed,
and can't be changed. If you wish to add an array to a compound
type, you must do so before the compound type is committed.
Example
=======
This example is from nf_test/ftst_types2.F.
C Define a compound type.
retval = nf_def_compound(ncid, cmp_size, type_name,
& cmp_typeid)
if (retval .ne. nf_noerr) call handle_err(retval)
C Include an array.
dim_sizes(1) = NX
dim_sizes(2) = NY
retval = nf_insert_array_compound(ncid, cmp_typeid, ary_name, 0,
& NF_INT, NDIMS, dim_sizes)
if (retval .ne. nf_noerr) call handle_err(retval)
5.6.4 Learn About a Compound Type: NF_INQ_COMPOUND
--------------------------------------------------
Get the number of fields, length in bytes, and name of a compound type.
In addtion to the NF_INQ_COMPOUND function, three additional
functions are provided which get only the name, size, and number of
fields.
Usage
=====
INTEGER FUNCTION NF_INQ_COMPOUND(INTEGER NCID, INTEGER XTYPE,
CHARACTER*(*) NAME, INTEGER SIZEP, INTEGER NFIELDSP)
INTEGER FUNCTION NF_INQ_COMPOUND_NAME(INTEGER NCID, INTEGER XTYPE,
CHARACTER*(*) NAME)
INTEGER FUNCTION NF_INQ_COMPOUND_SIZE(INTEGER NCID, INTEGER XTYPE,
INTEGER SIZEP)
INTEGER FUNCTION NF_INQ_COMPOUND_NFIELDS(INTEGER NCID, INTEGER XTYPE,
INTEGER NFIELDSP)
`NCID'
The ID of any group in the file that contains the compound type.
`XTYPE'
The typeid for this compound type, as returned by NF_DEF_COMPOUND,
or NF_INQ_VAR.
`NAME'
Character array which will get the name of the compound type. It
will have a maximum length of NF_MAX_NAME.
`SIZEP'
The size of the compound type in bytes will be put here.
`NFIELDSP'
The number of fields in the compound type will be placed here.
Return Codes
============
`NF_NOERR'
No error.
`NF_EBADID'
Couldn't find this ncid.
`NF_ENOTNC4'
Not a netCDF-4/HDF5 file.
`NF_ESTRICTNC3'
A netCDF-4/HDF5 file, but with CLASSIC_MODEL. No user defined types
are allowed in the classic model.
`NF_EBADTYPE'
This type not a compound type.
`NF_EBADTYPEID'
Bad type id.
`NF_EHDFERR'
An error was reported by the HDF5 layer.
Example
=======
This example is from nf_test/ftst_types.F.
C Check it differently.
retval = nf_inq_compound(ncid, typeids(1), name_in, size_in,
& nfields_in)
if (retval .ne. nf_noerr) call handle_err(retval)
if (name_in(1:len(type_name)) .ne. type_name .or.
& size_in .ne. WIND_T_SIZE .or. nfields_in .ne. 2) stop 2
C Check it one piece at a time.
retval = nf_inq_compound_nfields(ncid, typeids(1), nfields_in)
if (retval .ne. nf_noerr) call handle_err(retval)
if (nfields_in .ne. 2) stop 2
retval = nf_inq_compound_size(ncid, typeids(1), size_in)
if (retval .ne. nf_noerr) call handle_err(retval)
if (size_in .ne. WIND_T_SIZE) stop 2
retval = nf_inq_compound_name(ncid, typeids(1), name_in)
if (retval .ne. nf_noerr) call handle_err(retval)
if (name_in(1:len(type_name)) .ne. type_name) stop 2
5.6.5 Learn About a Field of a Compound Type: NF_INQ_COMPOUND_FIELD
-------------------------------------------------------------------
Get information about one of the fields of a compound type.
Usage
=====
INTEGER FUNCTION NF_INQ_COMPOUND_FIELD(INTEGER NCID, INTEGER XTYPE,
INTEGER FIELDID, CHARACTER*(*) NAME, INTEGER OFFSETP,
INTEGER FIELD_TYPEIDP, INTEGER NDIMSP, INTEGER DIM_SIZESP)
INTEGER FUNCTION NF_INQ_COMPOUND_FIELDNAME(INTEGER TYPEID,
INTEGER FIELDID, CHARACTER*(*) NAME)
INTEGER FUNCTION NF_INQ_COMPOUND_FIELDINDEX(INTEGER TYPEID,
CHARACTER*(*) NAME, INTEGER FIELDIDP)
INTEGER FUNCTION NF_INQ_COMPOUND_FIELDOFFSET(INTEGER TYPEID,
INTEGER FIELDID, INTEGER OFFSETP)
INTEGER FUNCTION NF_INQ_COMPOUND_FIELDTYPE(INTEGER TYPEID,
INTEGER FIELDID, INTEGER FIELD_TYPEIDP)
INTEGER FUNCTION NF_INQ_COMPOUND_FIELDNDIMS(INTEGER NCID,
INTEGER XTYPE, INTEGER FIELDID, INTEGER NDIMSP)
INTEGER FUNCTION NF_INQ_COMPOUND_FIELDDIM_SIZES(INTEGER NCID,
INTEGER XTYPE, INTEGER FIELDID, INTEGER DIM_SIZES)
`NCID'
The groupid where this compound type exists.
`XTYPE'
The typeid for this compound type, as returned by NF_DEF_COMPOUND,
or NF_INQ_VAR.
`FIELDID'
A one-based index number specifying a field in the compound type.
`NAME'
A character array which will get the name of the field. The name
will be NF_MAX_NAME characters, at most.
`OFFSETP'
An integer which will get the offset of the field.
`FIELD_TYPEID'
An integer which will get the typeid of the field.
`NDIMSP'
An integer which will get the number of dimensions of the field.
`DIM_SIZESP'
An integer array which will get the dimension sizes of the field.
Errors
======
`NF_NOERR'
No error.
`NF_EBADTYPEID'
Bad type id.
`NF_EHDFERR'
An error was reported by the HDF5 layer.
Example
=======
This example is from nf_test/fst_types.F.
C Check the first field of the compound type.
retval = nf_inq_compound_field(ncid, typeids(1), 1, name_in,
& offset_in, field_typeid_in, ndims_in, dim_sizes_in)
if (retval .ne. nf_noerr) call handle_err(retval)
if (name_in(1:len(u_name)) .ne. u_name .or. offset_in .ne. 0 .or.
& field_typeid_in .ne. NF_INT .or. ndims_in .ne. 0) stop 2
retval = nf_inq_compound_fieldname(ncid, typeids(1), 1, name_in)
if (retval .ne. nf_noerr) call handle_err(retval)
if (name_in(1:len(u_name)) .ne. u_name) stop 2
retval = nf_inq_compound_fieldoffset(ncid, typeids(1), 1,
& offset_in)
if (retval .ne. nf_noerr) call handle_err(retval)
if (offset_in .ne. 0) stop 2
retval = nf_inq_compound_fieldtype(ncid, typeids(1), 1,
& field_typeid_in)
if (retval .ne. nf_noerr) call handle_err(retval)
if (field_typeid_in .ne. NF_INT) stop 2
retval = nf_inq_compound_fieldndims(ncid, typeids(1), 1,
& ndims_in)
if (retval .ne. nf_noerr) call handle_err(retval)
if (ndims_in .ne. 0) stop 2
5.7 Variable Length Array Introduction
======================================
NetCDF-4 added support for a variable length array type. This is not
supported in classic or 64-bit offset files, or in netCDF-4 files which
were created with the NF_CLASSIC_MODEL flag.
A variable length array is represented in C as a structure from HDF5,
the nf_vlen_t structure. It contains a len member, which contains the
length of that array, and a pointer to the array.
So an array of VLEN in C is an array of nc_vlen_t structures. The
only way to handle this in Fortran is with a character buffer sized
correctly for the platform.
The extra access functions NF_GET_VLEN_ELEMENT and
NF_PUT_VLEN_ELEMENT to get and put one VLEN element. (That is, one
array of variable length.) When calling the put, the data are not
copied from the source. When calling the get the data are copied from
VLEN allocated memory, which must still be freed (see below).
VLEN arrays are handled differently with respect to allocation of
memory. Generally, when reading data, it is up to the user to malloc
(and subsequently free) the memory needed to hold the data. It is up to
the user to ensure that enough memory is allocated.
With VLENs, this is impossible. The user cannot know the size of an
array of VLEN until after reading the array. Therefore when reading
VLEN arrays, the netCDF library will allocate the memory for the data
within each VLEN.
It is up to the user, however, to eventually free this memory. This
is not just a matter of one call to free, with the pointer to the array
of VLENs; each VLEN contains a pointer which must be freed.
Compression is permitted but may not be effective for VLEN data,
because the compression is applied to the nc_vlen_t structures, rather
than the actual data.
5.7.1 Define a Variable Length Array (VLEN): NF_DEF_VLEN
--------------------------------------------------------
Use this function to define a variable length array type.
Usage
=====
INTEGER FUNCTION NF_DEF_VLEN(INTEGER NCID, CHARACTER*(*) NAME,
INTEGER BASE_TYPEID, INTEGER XTYPEP)
`NCID'
The ncid of the file to create the VLEN type in.
`NAME'
A name for the VLEN type.
`BASE_TYPEID'
The typeid of the base type of the VLEN. For example, for a VLEN of
shorts, the base type is NF_SHORT. This can be a user defined type.
`XTYPEP'
The typeid of the new VLEN type will be set here.
Errors
======
`NF_NOERR'
No error.
`NF_EMAXNAME'
NF_MAX_NAME exceeded.
`NF_ENAMEINUSE'
Name is already in use.
`NF_EBADNAME'
Attribute or variable name contains illegal characters.
`NF_EBADID'
ncid invalid.
`NF_EBADGRPID'
Group ID part of ncid was invalid.
`NF_EINVAL'
Size is invalid.
`NF_ENOMEM'
Out of memory.
Example
=======
This example is from nf_test/ftst_vars4.F.
C Create the vlen type.
retval = nf_def_vlen(ncid, vlen_type_name, nf_int, vlen_typeid)
if (retval .ne. nf_noerr) call handle_err(retval)
5.7.2 Learning about a Variable Length Array (VLEN) Type: NF_INQ_VLEN
---------------------------------------------------------------------
Use this type to learn about a vlen.
Usage
=====
INTEGER FUNCTION NF_INQ_VLEN(INTEGER NCID, INTEGER XTYPE,
CHARACTER*(*) NAME, INTEGER DATUM_SIZEP, INTEGER
BASE_NF_TYPEP)
`NCID'
The ncid of the file that contains the VLEN type.
`XTYPE'
The type of the VLEN to inquire about.
`NAME'
The name of the VLEN type. The name will be NF_MAX_NAME characters
or less.
`DATUM_SIZEP'
A pointer to a size_t, this will get the size of one element of
this vlen.
`BASE_NF_TYPEP'
An integer that will get the type of the VLEN base type. (In other
words, what type is this a VLEN of?)
Errors
======
`NF_NOERR'
No error.
`NF_EBADTYPE'
Can't find the typeid.
`NF_EBADID'
ncid invalid.
`NF_EBADGRPID'
Group ID part of ncid was invalid.
Example
=======
This example is from nf_test/ftst_vars4.F.
C Use nf_inq_vlen and make sure we get the same answers as we did
C with nf_inq_user_type.
retval = nf_inq_vlen(ncid, typeids(1), type_name, base_size,
& base_type)
if (retval .ne. nf_noerr) call handle_err(retval)
5.7.3 Releasing Memory for a Variable Length Array (VLEN) Type: NF_FREE_VLEN
----------------------------------------------------------------------------
When a VLEN is read into user memory from the file, the HDF5 library
performs memory allocations for each of the variable length arrays
contained within the VLEN structure. This memory must be freed by the
user to avoid memory leaks.
This violates the normal netCDF expectation that the user is
responsible for all memory allocation. But, with VLEN arrays, the
underlying HDF5 library allocates the memory for the user, and the user
is responsible for deallocating that memory.
Usage
=====
INTEGER FUNCTION NF_FREE_VLEN(CHARACTER VL);
`VL'
The variable length array structure which is to be freed.
Errors
======
`NF_NOERR'
No error.
`NF_EBADTYPE'
Can't find the typeid.
Example
=======
5.7.4 Set a Variable Length Array with NF_PUT_VLEN_ELEMENT
----------------------------------------------------------
Use this to set the element of the (potentially) n-dimensional array of
VLEN. That is, this sets the data in one variable length array.
Usage
=====
INTEGER FUNCTION NF_PUT_VLEN_ELEMENT(INTEGER NCID, INTEGER XTYPE,
CHARACTER*(*) VLEN_ELEMENT, INTEGER LEN, DATA)
`NCID'
The ncid of the file that contains the VLEN type.
`XTYPE'
The type of the VLEN.
`VLEN_ELEMENT'
The VLEN element to be set.
`LEN'
The number of entries in this array.
`DATA'
The data to be stored. Must match the base type of this VLEN.
Errors
======
`NF_NOERR'
No error.
`NF_EBADTYPE'
Can't find the typeid.
`NF_EBADID'
ncid invalid.
`NF_EBADGRPID'
Group ID part of ncid was invalid.
Example
=======
This example is from nf_test/ftst_vars4.F.
C Set up the vlen with this helper function, since F77 can't deal
C with pointers.
retval = nf_put_vlen_element(ncid, vlen_typeid, vlen,
& vlen_len, data1)
if (retval .ne. nf_noerr) call handle_err(retval)
5.7.5 Set a Variable Length Array with NF_GET_VLEN_ELEMENT
----------------------------------------------------------
Use this to set the element of the (potentially) n-dimensional array of
VLEN. That is, this sets the data in one variable length array.
Usage
=====
INTEGER FUNCTION NF_GET_VLEN_ELEMENT(INTEGER NCID, INTEGER XTYPE,
CHARACTER*(*) VLEN_ELEMENT, INTEGER LEN, DATA)
`NCID'
The ncid of the file that contains the VLEN type.
`XTYPE'
The type of the VLEN.
`VLEN_ELEMENT'
The VLEN element to be set.
`LEN'
This will be set to the number of entries in this array.
`DATA'
The data will be copied here. Sufficient storage must be available
or bad things will happen to you.
Errors
======
`NF_NOERR'
No error.
`NF_EBADTYPE'
Can't find the typeid.
`NF_EBADID'
ncid invalid.
`NF_EBADGRPID'
Group ID part of ncid was invalid.
Example
=======
This example is from nf_test/ftst_vars4.F.
C Read the vlen attribute.
retval = nf_get_att(ncid, NF_GLOBAL, 'att1', vlen_in)
if (retval .ne. nf_noerr) call handle_err(retval)
C Get the data from the vlen we just read.
retval = nf_get_vlen_element(ncid, vlen_typeid, vlen_in,
& vlen_len_in, data1_in)
if (retval .ne. nf_noerr) call handle_err(retval)
5.8 Opaque Type Introduction
============================
NetCDF-4 added support for the opaque type. This is not supported in
classic or 64-bit offset files.
The opaque type is a type which is a collection of objects of a known
size. (And each object is the same size). Nothing is known to netCDF
about the contents of these blobs of data, except their size in bytes,
and the name of the type.
To use an opaque type, first define it with *note NF_DEF_OPAQUE::. If
encountering an enum type in a new data file, use *note NF_INQ_OPAQUE::
to learn its name and size.
5.8.1 Creating Opaque Types: NF_DEF_OPAQUE
------------------------------------------
Create an opaque type. Provide a size and a name.
Usage
=====
INTEGER FUNCTION NF_DEF_OPAQUE(INTEGER NCID, CHARACTER*(*) NAME,
INTEGER SIZE, INTEGER TYPEIDP)
`NCID'
The groupid where the type will be created. The type may be used
anywhere in the file, no matter what group it is in.
`NAME'
The name for this type. Must be shorter than NF_MAX_NAME.
`SIZE'
The size of each opaque object.
`TYPEIDP'
Pointer where the new typeid for this type is returned. Use this
typeid when defining variables of this type with *note
NF_DEF_VAR::.
Errors
======
`NF_NOERR'
No error.
`NF_EBADTYPEID'
Bad typeid.
`NF_EBADFIELDID'
Bad fieldid.
`NF_EHDFERR'
An error was reported by the HDF5 layer.
Example
=======
This example is from nf_test/ftst_vars3.F.
C Create the opaque type.
retval = nf_def_opaque(ncid, opaque_size, opaque_type_name,
& opaque_typeid)
if (retval .ne. nf_noerr) call handle_err(retval)
5.8.2 Learn About an Opaque Type: NF_INQ_OPAQUE
-----------------------------------------------
Given a typeid, get the information about an opaque type.
Usage
=====
INTEGER FUNCTION NF_INQ_OPAQUE(INTEGER NCID, INTEGER XTYPE,
CHARACTER*(*) NAME, INTEGER SIZEP)
`NCID'
The ncid for the group containing the opaque type.
`XTYPE'
The typeid for this opaque type, as returned by NF_DEF_COMPOUND, or
NF_INQ_VAR.
`NAME'
The name of the opaque type will be copied here. It will be
NF_MAX_NAME bytes or less.
`SIZEP'
The size of the opaque type will be copied here.
Errors
======
`NF_NOERR'
No error.
`NF_EBADTYPEID'
Bad typeid.
`NF_EBADFIELDID'
Bad fieldid.
`NF_EHDFERR'
An error was reported by the HDF5 layer.
Example
=======
This example is from nf_test/ftst_vars3.F.
C Use nf_inq_opaque and make sure we get the same answers as we did
C with nf_inq_user_type.
retval = nf_inq_opaque(ncid, typeids(2), type_name, base_size)
if (retval .ne. nf_noerr) call handle_err(retval)
5.9 Enum Type Introduction
==========================
NetCDF-4 added support for the enum type. This is not supported in
classic or 64-bit offset files.
5.9.1 Creating a Enum Type: NF_DEF_ENUM
---------------------------------------
Create an enum type. Provide an ncid, a name, and a base integer type.
After calling this function, fill out the type with repeated calls to
NF_INSERT_ENUM (*note NF_INSERT_ENUM::). Call NF_INSERT_ENUM once for
each value you wish to make part of the enumeration.
Usage
=====
INTEGER FUNCTION NF_DEF_ENUM(INTEGER NCID, INTEGER BASE_TYPEID,
CHARACTER*(*) NAME, INTEGER TYPEIDP)
`NCID'
The groupid where this compound type will be created.
`BASE_TYPEID'
The base integer type for this enum. Must be one of: NF_BYTE,
NF_UBYTE, NF_SHORT, NF_USHORT, NF_INT, NF_UINT, NF_INT64,
NF_UINT64.
`NAME'
The name of the new enum type.
`TYPEIDP'
The typeid of the new type will be placed here.
Errors
======
`NF_NOERR'
No error.
`NF_EBADID'
Bad group id.
`NF_ENAMEINUSE'
That name is in use. Compound type names must be unique in the data
file.
`NF_EMAXNAME'
Name exceeds max length NF_MAX_NAME.
`NF_EBADNAME'
Name contains illegal characters.
`NF_ENOTNC4'
Attempting a netCDF-4 operation on a netCDF-3 file. NetCDF-4
operations can only be performed on files defined with a create
mode which includes flag NF_NETCDF4. (*note NF_OPEN::).
`NF_ESTRICTNC3'
This file was created with the strict netcdf-3 flag, therefore
netcdf-4 operations are not allowed. (*note NF_OPEN::).
`NF_EHDFERR'
An error was reported by the HDF5 layer.
`NF_EPERM'
Attempt to write to a read-only file.
`NF_ENOTINDEFINE'
Not in define mode.
This example is from nf_test/ftst_vars3.F.
C Create the enum type.
retval = nf_def_enum(ncid, NF_INT, enum_type_name, enum_typeid)
if (retval .ne. nf_noerr) call handle_err(retval)
5.9.2 Inserting a Field into a Enum Type: NF_INSERT_ENUM
--------------------------------------------------------
Insert a named member into a enum type.
Usage
=====
INTEGER FUNCTION NF_INSERT_ENUM(INTEGER NCID, INTEGER XTYPE,
CHARACTER IDENTIFIER, INTEGER VALUE)
`NCID'
The ncid of the group which contains the type.
`TYPEID'
The typeid for this enum type, as returned by nf_def_enum, or
nf_inq_var.
`IDENTIFIER'
The identifier of the new member.
`VALUE'
The value that is to be associated with this member.
Errors
======
`NF_NOERR'
No error.
`NF_EBADID'
Bad group id.
`NF_ENAMEINUSE'
That name is in use. Field names must be unique within a enum type.
`NF_EMAXNAME'
Name exceed max length NF_MAX_NAME.
`NF_EBADNAME'
Name contains illegal characters.
`NF_ENOTNC4'
Attempting a netCDF-4 operation on a netCDF-3 file. NetCDF-4
operations can only be performed on files defined with a create
mode which includes flag NF_NETCDF4. (*note NF_OPEN::).
`NF_ESTRICTNC3'
This file was created with the strict netcdf-3 flag, therefore
netcdf-4 operations are not allowed. (*note NF_OPEN::).
`NF_EHDFERR'
An error was reported by the HDF5 layer.
`NF_ENOTINDEFINE'
Not in define mode.
Example
=======
This example is from nf_test/ftst_vars3.F.
one = 1
zero = 0
retval = nf_insert_enum(ncid, enum_typeid, zero_name, zero)
if (retval .ne. nf_noerr) call handle_err(retval)
retval = nf_insert_enum(ncid, enum_typeid, one_name, one)
if (retval .ne. nf_noerr) call handle_err(retval)
5.9.3 Learn About a Enum Type: NF_INQ_ENUM
------------------------------------------
Get information about a user-defined enumeration type.
Usage
=====
INTEGER FUNCTION NF_INQ_ENUM(INTEGER NCID, INTEGER XTYPE,
CHARACTER*(*) NAME, INTEGER BASE_NF_TYPE, INTEGER BASE_SIZE,
INTEGER NUM_MEMBERS)
`NCID'
The group ID of the group which holds the enum type.
`XTYPE'
The typeid for this enum type, as returned by NF_DEF_ENUM, or
NF_INQ_VAR.
`NAME'
Character array which will get the name. It will have a maximum
length of NF_MAX_NAME.
`BASE_NF_TYPE'
An integer which will get the base integer type of this enum.
`BASE_SIZE'
An integer which will get the size (in bytes) of the base integer
type of this enum.
`NUM_MEMBERS'
An integer which will get the number of members defined for this
enumeration type.
Errors
======
`NF_NOERR'
No error.
`NF_EBADTYPEID'
Bad type id.
`NF_EHDFERR'
An error was reported by the HDF5 layer.
Example
=======
In this example from nf_test/ftst_vars3.F, an enum type is created and
then examined:
retval = nf_inq_enum(ncid, typeids(1), type_name, base_type,
& base_size, num_members)
if (retval .ne. nf_noerr) call handle_err(retval)
if (base_type .ne. NF_INT .or. num_members .ne. 2) stop 2
5.9.4 Learn the Name of a Enum Type: nf_inq_enum_member
-------------------------------------------------------
Get information about a member of an enum type.
Usage
=====
INTEGER FUNCTION NF_INQ_ENUM_MEMBER(INTEGER NCID, INTEGER XTYPE,
INTEGER IDX, CHARACTER*(*) NAME, INTEGER VALUE)
`NCID'
The groupid where this enum type exists.
`XTYPE'
The typeid for this enum type.
`IDX'
The one-based index number for the member of interest.
`NAME'
A character array which will get the name of the member. It will
have a maximum length of NF_MAX_NAME.
`VALUE'
An integer that will get the value associated with this member.
Errors
======
`NF_NOERR'
No error.
`NF_EBADTYPEID'
Bad type id.
`NF_EHDFERR'
An error was reported by the HDF5 layer.
Example
=======
This example is from nf_test/ftst_vars3.F:
C Check the members of the enum type.
retval = nf_inq_enum_member(ncid, typeids(1), 1, member_name,
& member_value)
if (retval .ne. nf_noerr) call handle_err(retval)
if (member_name(1:len(zero_name)) .ne. zero_name .or.
& member_value .ne. 0) stop 2
retval = nf_inq_enum_member(ncid, typeids(1), 2, member_name,
& member_value)
if (retval .ne. nf_noerr) call handle_err(retval)
if (member_name(1:len(one_name)) .ne. one_name .or.
& member_value .ne. 1) stop 2
5.9.5 Learn the Name of a Enum Type: NF_INQ_ENUM_IDENT
------------------------------------------------------
Get the name which is associated with an enum member value.
This is similar to NF_INQ_ENUM_MEMBER, but instead of using the index
of the member, you use the value of the member.
Usage
=====
INTEGER FUNCTION NF_INQ_ENUM_IDENT(INTEGER NCID, INTEGER XTYPE,
INTEGER VALUE, CHARACTER*(*) IDENTIFIER)
`NCID'
The groupid where this enum type exists.
`XTYPE'
The typeid for this enum type.
`VALUE'
The value for which an identifier is sought.
`IDENTIFIER'
A character array that will get the identifier. It will have a
maximum length of NF_MAX_NAME.
Return Code
===========
`NF_NOERR'
No error.
`NF_EBADTYPEID'
Bad type id, or not an enum type.
`NF_EHDFERR'
An error was reported by the HDF5 layer.
`NF_EINVAL'
The value was not found in the enum.
Example
=======
In this example from nf_test/ftst_vars3.F, the values for 0 and 1 are
checked in an enum.
retval = nf_inq_enum_ident(ncid, typeids(1), 0, member_name)
if (retval .ne. nf_noerr) call handle_err(retval)
if (member_name(1:len(zero_name)) .ne. zero_name) stop 2
retval = nf_inq_enum_ident(ncid, typeids(1), 1, member_name)
if (retval .ne. nf_noerr) call handle_err(retval)
if (member_name(1:len(one_name)) .ne. one_name) stop 2
6 Variables
***********
6.1 Variables Introduction
==========================
Variables for a netCDF dataset are defined when the dataset is created,
while the netCDF dataset is in define mode. Other variables may be
added later by reentering define mode. A netCDF variable has a name, a
type, and a shape, which are specified when it is defined. A variable
may also have values, which are established later in data mode.
Ordinarily, the name, type, and shape are fixed when the variable is
first defined. The name may be changed, but the type and shape of a
variable cannot be changed. However, a variable defined in terms of the
unlimited dimension can grow without bound in that dimension.
A netCDF variable in an open netCDF dataset is referred to by a small
integer called a variable ID.
Variable IDs reflect the order in which variables were defined within
a netCDF dataset. Variable IDs are 1, 2, 3,..., in the order in which
the variables were defined. A function is available for getting the
variable ID from the variable name and vice-versa.
Attributes (see *note Attributes::) may be associated with a
variable to specify such properties as units.
Operations supported on variables are:
* Create a variable, given its name, data type, and shape.
* Get a variable ID from its name.
* Get a variable's name, data type, shape, and number of attributes
from its ID.
* Put a data value into a variable, given variable ID, indices, and
value.
* Put an array of values into a variable, given variable ID, corner
indices, edge lengths, and a block of values.
* Put a subsampled or mapped array-section of values into a variable,
given variable ID, corner indices, edge lengths, stride vector,
index mapping vector, and a block of values.
* Get a data value from a variable, given variable ID and indices.
* Get an array of values from a variable, given variable ID, corner
indices, and edge lengths.
* Get a subsampled or mapped array-section of values from a variable,
given variable ID, corner indices, edge lengths, stride vector, and
index mapping vector.
* Rename a variable.
6.2 Language Types Corresponding to netCDF external data types
==============================================================
The following table gives the netCDF external data types and the
corresponding type constants for defining variables in the FORTRAN
interface:
Type FORTRAN API Mnemonic Bits
byte NF_BYTE 8
char NF_CHAR 8
short NF_SHORT 16
int NF_INT 32
float NF_FLOAT 32
double NF_DOUBLE 64
The first column gives the netCDF external data type, which is the
same as the CDL data type. The next column gives the corresponding
FORTRAN parameter for use in netCDF functions (the parameters are
defined in the netCDF FORTRAN include-file netcdf.inc). The last column
gives the number of bits used in the external representation of values
of the corresponding type.
Note that there are no netCDF types corresponding to 64-bit integers
or to characters wider than 8 bits in the current version of the netCDF
library.
6.3 Create a Variable: `NF_DEF_VAR'
===================================
The function NF_DEF_VAR adds a new variable to an open netCDF dataset
in define mode. It returns (as an argument) a variable ID, given the
netCDF ID, the variable name, the variable type, the number of
dimensions, and a list of the dimension IDs.
Usage
=====
INTEGER FUNCTION NF_DEF_VAR(INTEGER NCID, CHARACTER*(*) NAME,
INTEGER XTYPE, INTEGER NVDIMS,
INTEGER VDIMS(*), INTEGER varid)
`NCID'
NetCDF ID, from a previous call to NF_OPEN or NF_CREATE.
`NAME'
Variable name.
`XTYPE'
One of the set of predefined netCDF external data types. The type
of this parameter, NF_TYPE, is defined in the netCDF header file.
The valid netCDF external data types are NF_BYTE, NF_CHAR,
NF_SHORT, NF_INT, NF_FLOAT, and NF_DOUBLE. If the file is a
NetCDF-4/HDF5 file, the additional types NF_UBYTE, NF_USHORT,
NF_UINT, NF_INT64, NF_UINT64, and NF_STRING may be used, as well
as a user defined type ID.
`NVDIMS'
Number of dimensions for the variable. For example, 2 specifies a
matrix, 1 specifies a vector, and 0 means the variable is a scalar
with no dimensions. Must not be negative or greater than the
predefined constant NF_MAX_VAR_DIMS.
`VDIMS'
Vector of ndims dimension IDs corresponding to the variable
dimensions. If the ID of the unlimited dimension is included, it
must be first. This argument is ignored if ndims is 0. For
expanded model netCDF4/HDF5 files, there may be any number of
unlimited dimensions, and they may be used in any element of the
dimids array.
`varid'
Returned variable ID.
Errors
======
NF_DEF_VAR returns the value NF_NOERR if no errors occurred. Otherwise,
the returned status indicates an error. Possible causes of errors
include:
* The netCDF dataset is not in define mode.
* The specified variable name is the name of another existing
variable.
* The specified type is not a valid netCDF type.
* The specified number of dimensions is negative or more than the
constant NF_MAX_VAR_DIMS, the maximum number of dimensions
permitted for a netCDF variable.
* One or more of the dimension IDs in the list of dimensions is not a
valid dimension ID for the netCDF dataset.
* The number of variables would exceed the constant NF_MAX_VARS, the
maximum number of variables permitted in a netCDF dataset.
* The specified netCDF ID does not refer to an open netCDF dataset.
Example
=======
Here is an example using NF_DEF_VAR to create a variable named rh of
type double with three dimensions, time, lat, and lon in a new netCDF
dataset named foo.nc:
INCLUDE 'netcdf.inc'
...
INTEGER STATUS, NCID
INTEGER LATDIM, LONDIM, TIMDIM ! dimension IDs
INTEGER RHID ! variable ID
INTEGER RHDIMS(3) ! variable shape
...
STATUS = NF_CREATE ('foo.nc', NF_NOCLOBBER, NCID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
! define dimensions
STATUS = NF_DEF_DIM(NCID, 'lat', 5, LATDIM)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
STATUS = NF_DEF_DIM(NCID, 'lon', 10, LONDIM)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
STATUS = NF_DEF_DIM(NCID, 'time', NF_UNLIMITED, TIMDIM)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
! define variable
RHDIMS(1) = LONDIM
RHDIMS(2) = LATDIM
RHDIMS(3) = TIMDIM
STATUS = NF_DEF_VAR (NCID, 'rh', NF_DOUBLE, 3, RHDIMS, RHID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
6.4 Define Chunking Parameters for a Variable: `NF_DEF_VAR_CHUNKING'
====================================================================
The function NF_DEF_VAR_CHUNKING sets the storage parameters for a
variable in a netCDF-4 file. It can set the chunk sizes to get chunked
storage, or it can set the contiguous flag to get contiguous storage.
Variables that make use of one or more unlimited dimensions,
compression, or checksums must use chunking. Such variables are
created with default chunk sizes of 1 for each unlimited dimension and
the dimension length for other dimensions, except that if the resulting
chunks are too large, the default chunk sizes for non-record dimensions
are reduced.
The total size of a chunk must be less than 4 GiB. That is, the
product of all chunksizes and the size of the data (or the size of
nc_vlen_t for VLEN types) must be less than 4 GiB.
This function may only be called after the variable is defined, but
before nc_enddef is called. Once the chunking parameters are set for a
variable, they cannot be changed. This function can be used to change
the default chunking for record, compressed, or checksummed variables
before nc_enddef is called.
Note that you cannot set chunking for scalar variables. Only
non-scalar variables can have chunking.
Usage
=====
NF_DEF_VAR_CHUNKING(INTEGER NCID, INTEGER VARID, INTEGER STORAGE, INTEGER CHUNKSIZES)
`ncid'
NetCDF ID, from a previous call to NF_OPEN or NF_CREATE.
`varid'
Variable ID.
`storage'
If NF_CONTIGUOUS, then contiguous storage is used for this
variable. Variables with compression, shuffle filter, checksums, or
one or more unlimited dimensions cannot use contiguous storage. If
contiguous storage is turned on, the chunksizes parameter is
ignored.
If NF_CHUNKED, then chunked storage is used for this variable.
Chunk sizes may be specified with the chunksizes parameter.
Default sizes will be used if chunking is required and this
function is not called.
By default contiguous storage is used for fix-sized variables when
conpression, chunking, checksums, or endianness control are not
used.
`chunksizes'
An array of chunk sizes. The array must have the one chunksize for
each dimension in the variable. If contiguous storage is used,
then the chunksizes parameter is ignored.
Errors
======
NF_DEF_VAR_CHUNKING returns the value NF_NOERR if no errors occurred.
Otherwise, the returned status indicates an error.
Possible return codes include:
`NF_NOERR'
No error.
`NF_BADID'
Bad ncid.
`NF_EINVAL'
Invalid input. This can occur when the user attempts to set
contiguous storage for a variable with compression or checksums,
or one or more unlimited dimensions.
`NF_ENOTNC4'
Not a netCDF-4 file.
`NF_ENOTVAR'
Can't find this variable.
`NF_ELATEDEF'
This variable has already been the subject of a NF_ENDDEF call. In
netCDF-4 files NF_ENDDEF will be called automatically for any data
read or write. Once enddef has been called, it is impossible to set
the chunking for a variable.
`NF_ENOTINDEFINE'
Not in define mode. This is returned for netCDF classic or 64-bit
offset files, or for netCDF-4 files, when they were been created
with NF_STRICT_NC3 flag. (*note NF_CREATE::).
`NF_ESTRICTNC3'
Trying to create a var some place other than the root group in a
netCDF file with NF_STRICT_NC3 turned on.
Example
=======
In this example from nf_test/ftst_vars.F, a file is created, two
dimensions and a variable are defined, and the chunksizes of the data
are set to the size of the data (that is, data will be written in one
chunk).
C Create the netCDF file.
retval = nf_create(FILE_NAME, NF_NETCDF4, ncid)
if (retval .ne. nf_noerr) call handle_err(retval)
C Define the dimensions.
retval = nf_def_dim(ncid, "x", NX, x_dimid)
if (retval .ne. nf_noerr) call handle_err(retval)
retval = nf_def_dim(ncid, "y", NY, y_dimid)
if (retval .ne. nf_noerr) call handle_err(retval)
C Define the variable.
dimids(1) = y_dimid
dimids(2) = x_dimid
retval = NF_DEF_VAR(ncid, "data", NF_INT, NDIMS, dimids, varid)
if (retval .ne. nf_noerr) call handle_err(retval)
C Turn on chunking.
chunks(1) = NY
chunks(2) = NX
retval = NF_DEF_VAR_chunking(ncid, varid, NF_CHUNKED, chunks)
if (retval .ne. nf_noerr) call handle_err(retval)
6.5 Learn About Chunking Parameters for a Variable: `NF_INQ_VAR_CHUNKING'
=========================================================================
The function NF_INQ_VAR_CHUNKING returns the chunking settings for a
variable in a netCDF-4 file.
Usage
=====
NF_INQ_VAR_CHUNKING(INTEGER NCID, INTEGER VARID, INTEGER STORAGE, INTEGER CHUNKSIZES);
`NCID'
NetCDF ID, from a previous call to NF_OPEN or NF_CREATE.
`VARID'
Variable ID.
`STORAGE'
On return, set to NF_CONTIGUOUS if this variable uses contiguous
storage, NF_CHUNKED if it uses chunked storage.
`CHUNKSIZES'
An array of chunk sizes. The length of CHUNKSIZES must be the
same as the number of dimensions of the variable.
Errors
======
NF_INQ_VAR_CHUNKING returns the value NF_NOERR if no errors occurred.
Otherwise, the returned status indicates an error.
Possible return codes include:
`NF_NOERR'
No error.
`NF_BADID'
Bad ncid.
`NF_ENOTNC4'
Not a netCDF-4 file.
`NF_ENOTVAR'
Can't find this variable.
Example
=======
In this example from nf_test/ftst_vars.F, a variable with chunked
storage is checked to ensure that the chunksizes are set to expected
values.
C Is everything set that is supposed to be?
retval = nf_inq_var_chunking(ncid, varid, storage, chunks_in)
if (retval .ne. nf_noerr) call handle_err(retval)
if (storage .ne. NF_CHUNKED) stop 2
if (chunks(1) .ne. chunks_in(1)) stop 2
if (chunks(2) .ne. chunks_in(2)) stop 2
6.6 Set HDF5 Chunk Cache for a Variable: NF_SET_VAR_CHUNK_CACHE
===============================================================
This function changes the chunk cache settings for a variable. The
change in cache size happens immediately. This is a property of the
open file - it does not persist the next time you open the file.
For more information, see the documentation for the H5Pset_cache()
function in the HDF5 library at the HDF5 website:
`http://hdfgroup.org/HDF5/'.
Usage
=====
nc_set_var_chunk_cache(int ncid, int varid, size_t size, size_t nelems,
float preemption);
`ncid'
NetCDF ID, from a previous call to nc_open or nc_create.
`varid'
Variable ID.
`size'
The total size of the raw data chunk cache, in megabytes. This
should be big enough to hold multiple chunks of data. (Note that
the C API uses bytes, but the Fortran APIs uses megabytes to avoid
numbers that can't fit in 4-byte integers.)
`nelems'
The number of chunk slots in the raw data chunk cache hash table.
This should be a prime number larger than the number of chunks
that will be in the cache.
`preemption'
The preemtion value must be between 0 and 100 inclusive and
indicates how much chunks that have been fully read are favored for
preemption. A value of zero means fully read chunks are treated no
differently than other chunks (the preemption is strictly LRU)
while a value of 100 means fully read chunks are always preempted
before other chunks. (The C API uses a float between 0 and 1 for
this value).
Return Codes
============
`NF_NOERR'
No error.
`NF_EINVAL'
Preemption must be between zero and 100 (inclusive).
Example
=======
This example is from nf_test/ftst_vars2.F:
include 'netcdf.inc'
...
C These will be used to set the per-variable chunk cache.
integer CACHE_SIZE, CACHE_NELEMS, CACHE_PREEMPTION
parameter (CACHE_SIZE = 8, CACHE_NELEMS = 571)
parameter (CACHE_PREEMPTION = 42)
...
C Set variable caches.
retval = nf_set_var_chunk_cache(ncid, varid(i), CACHE_SIZE,
& CACHE_NELEMS, CACHE_PREEMPTION)
if (retval .ne. nf_noerr) call handle_err(retval)
6.7 Get the HDF5 Chunk Cache Settings for a variable: NF_GET_VAR_CHUNK_CACHE
============================================================================
This function gets the current chunk cache settings for a variable in a
netCDF-4/HDF5 file.
For more information, see the documentation for the H5Pget_cache()
function in the HDF5 library at the HDF5 website:
`http://hdfgroup.org/HDF5/'.
Usage
=====
INTEGER NF_GET_VAR_CHUNK_CACHE(INTEGER NCID, INTEGER VARID, INTEGER SIZE, INTEGER NELEMS,
INTEGER PREEMPTION);
`ncid'
NetCDF ID, from a previous call to NF_OPEN or NF_CREATE.
`varid'
Variable ID.
`sizep'
The total size of the raw data chunk cache, in megabytes, will be
put here.
`nelemsp'
The number of chunk slots in the raw data chunk cache hash table
will be put here.
`preemptionp'
The preemption will be put here. The preemtion value is between 0
and 100 inclusive and indicates how much chunks that have been
fully read are favored for preemption. A value of zero means
fully read chunks are treated no differently than other chunks
(the preemption is strictly LRU) while a value of 100 means fully
read chunks are always preempted before other chunks.
Return Codes
============
`NC_NOERR'
No error.
Example
=======
This example is from nf_test/ftst_vars2.c:
include 'netcdf.inc'
...
C These will be used to set the per-variable chunk cache.
integer CACHE_SIZE, CACHE_NELEMS, CACHE_PREEMPTION
parameter (CACHE_SIZE = 8, CACHE_NELEMS = 571)
parameter (CACHE_PREEMPTION = 42)
C These will be used to check the setting of the per-variable chunk
C cache.
integer cache_size_in, cache_nelems_in, cache_preemption_in
...
retval = nf_get_var_chunk_cache(ncid, varid(i), cache_size_in,
& cache_nelems_in, cache_preemption_in)
if (retval .ne. nf_noerr) call handle_err(retval)
if (cache_size_in .ne. CACHE_SIZE .or. cache_nelems_in .ne.
& CACHE_NELEMS .or. cache_preemption .ne. CACHE_PREEMPTION)
& stop 8
6.8 Define Fill Parameters for a Variable: `nf_def_var_fill'
============================================================
The function NF_DEF_VAR_FILL sets the fill parameters for a variable in
a netCDF-4 file.
This function must be called after the variable is defined, but
before NF_ENDDEF is called.
Usage
=====
NF_DEF_VAR_FILL(INTEGER NCID, INTEGER VARID, INTEGER NO_FILL, FILL_VALUE);
`NCID'
NetCDF ID, from a previous call to NF_OPEN or NF_CREATE.
`VARID'
Variable ID.
`NO_FILL'
Set to non-zero value to set no_fill mode on a variable. When this
mode is on, fill values will not be written for the variable. This
is helpful in high performance applications. For netCDF-4/HDF5
files (whether classic model or not), this may only be changed
after the variable is defined, but before it is committed to disk
(i.e. before the first NF_ENDDEF after the NF_DEF_VAR.) For
classic and 64-bit offset file, the no_fill mode may be turned on
and off at any time.
`FILL_VALUE'
A value which will be used as the fill value for the variable.
Must be the same type as the variable. This will be written to a
_FillValue attribute, created for this purpose. If NULL, this
argument will be ignored.
Return Codes
============
`NF_NOERR'
No error.
`NF_BADID'
Bad ncid.
`NF_ENOTNC4'
Not a netCDF-4 file.
`NF_ENOTVAR'
Can't find this variable.
`NF_ELATEDEF'
This variable has already been the subject of a NF_ENDDEF call. In
netCDF-4 files NF_ENDDEF will be called automatically for any data
read or write. Once enddef has been called, it is impossible to set
the fill for a variable.
`NF_ENOTINDEFINE'
Not in define mode. This is returned for netCDF classic or 64-bit
offset files, or for netCDF-4 files, when they were been created
with NF_STRICT_NC3 flag. (*note NF_CREATE::).
`NF_EPERM'
Attempt to create object in read-only file.
Example
=======
6.9 Learn About Fill Parameters for a Variable: `NF_INQ_VAR_FILL'
=================================================================
The function NF_INQ_VAR_FILL returns the fill settings for a variable
in a netCDF-4 file.
Usage
=====
NF_INQ_VAR_FILL(INTEGER NCID, INTEGER VARID, INTEGER NO_FILL, FILL_VALUE)
`NCID'
NetCDF ID, from a previous call to NF_OPEN or NF_CREATE.
`VARID'
Variable ID.
`NO_FILL'
An integer which will get a 1 if no_fill mode is set for this
variable, and a zero if it is not set
`FILL_VALUE'
This will get the fill value for this variable. This parameter
will be ignored if it is NULL.
Return Codes
============
`NF_NOERR'
No error.
`NF_BADID'
Bad ncid.
`NF_ENOTNC4'
Not a netCDF-4 file.
`NF_ENOTVAR'
Can't find this variable.
Example
=======
6.10 Define Compression Parameters for a Variable: `NF_DEF_VAR_DEFLATE'
=======================================================================
The function NF_DEF_VAR_DEFLATE sets the deflate parameters for a
variable in a netCDF-4 file.
When using parallel I/O for writing data, deflate cannot be used.
This is because the compression makes it impossible for the HDF5
library to exactly map the data to disk location.
(Deflated data can be read with parallel I/O).
NF_DEF_VAR_DEFLATE must be called after the variable is defined, but
before NF_ENDDEF is called.
Usage
=====
NF_DEF_VAR_DEFLATE(INTEGER NCID, INTEGER VARID, INTEGER SHUFFLE, INTEGER DEFLATE,
INTEGER DEFLATE_LEVEL);
`NCID'
NetCDF ID, from a previous call to NF_OPEN or NF_CREATE.
`VARID'
Variable ID.
`SHUFFLE'
If non-zero, turn on the shuffle filter.
`DEFLATE'
If non-zero, turn on the deflate filter at the level specified by
the deflate_level parameter.
`DEFLATE_LEVEL'
Must be between 0 (no deflate, the default) and 9 (slowest, but
"best" deflate).
If set to zero, no deflation takes place and the def_var_deflate
call is ignored. This is slightly different from HDF5 handing of 0
deflate, which turns on the filter but makes only trivial changes
to the data.
Informal testing at NetCDF World Headquarters suggests that there
is little to be gained (with the limited set of test data used
here), in setting the deflate level above 2 or 3.
Errors
======
NF_DEF_VAR_DEFLATE returns the value NF_NOERR if no errors occurred.
Otherwise, the returned status indicates an error.
Possible return codes include:
`NF_NOERR'
No error.
`NF_BADID'
Bad ncid.
`NF_ENOTNC4'
Not a netCDF-4 file.
`NF_ENOTVAR'
Can't find this variable.
`NF_ELATEDEF'
This variable has already been the subject of a NF_ENDDEF call. In
netCDF-4 files NF_ENDDEF will be called automatically for any data
read or write. Once enddef has been called, it is impossible to set
the deflate for a variable.
`NF_ENOTINDEFINE'
Not in define mode. This is returned for netCDF classic or 64-bit
offset files, or for netCDF-4 files, when they were been created
with NF_STRICT_NC3 flag. (*note NF_CREATE::).
`NF_EPERM'
Attempt to create object in read-only file.
`NF_EINVAL'
Invalid deflate_level. The deflate level must be between 0 and 9,
inclusive.
Example
=======
In this example from nf_test/ftst_vars.F, a file is created with two
dimensions and one variable. Chunking, deflate, and the fletcher32
filter are turned on. The deflate level is set to 4 below.
C Create the netCDF file.
retval = nf_create(FILE_NAME, NF_NETCDF4, ncid)
if (retval .ne. nf_noerr) call handle_err(retval)
C Define the dimensions.
retval = nf_def_dim(ncid, "x", NX, x_dimid)
if (retval .ne. nf_noerr) call handle_err(retval)
retval = nf_def_dim(ncid, "y", NY, y_dimid)
if (retval .ne. nf_noerr) call handle_err(retval)
C Define the variable.
dimids(1) = y_dimid
dimids(2) = x_dimid
retval = NF_DEF_VAR(ncid, "data", NF_INT, NDIMS, dimids, varid)
if (retval .ne. nf_noerr) call handle_err(retval)
C Turn on chunking.
chunks(1) = NY
chunks(2) = NX
retval = NF_DEF_VAR_CHUNKING(ncid, varid, NF_CHUNKED, chunks)
if (retval .ne. nf_noerr) call handle_err(retval)
C Turn on deflate compression, fletcher32 checksum.
retval = NF_DEF_VAR_deflate(ncid, varid, 0, 1, 4)
if (retval .ne. nf_noerr) call handle_err(retval)
retval = NF_DEF_VAR_FLETCHER32(ncid, varid, NF_FLETCHER32)
if (retval .ne. nf_noerr) call handle_err(retval)
6.11 Learn About Deflate Parameters for a Variable: `NF_INQ_VAR_DEFLATE'
========================================================================
The function NF_INQ_VAR_DEFLATE returns the deflate settings for a
variable in a netCDF-4 file.
It is not necessary to know the deflate settings to read the
variable. (Deflate is completely transparent to readers of the data).
Usage
=====
NF_INQ_VAR_DEFLATE(INTEGER NCID, INTEGER VARID, INTEGER SHUFFLE,
INTEGER DEFLATE, INTEGER DEFLATE_LEVEL);
`NCID'
NetCDF ID, from a previous call to NF_OPEN or NF_CREATE.
`VARID'
Variable ID.
`SHUFFLE'
NF_INQ_VAR_DEFLATE will set this to a 1 if the shuffle filter is
turned on for this variable, and a 0 otherwise.
`DEFLATE'
NF_INQ_VAR_DEFLATE will set this to a 1 if the deflate filter is
turned on for this variable, and a 0 otherwise.
`DEFLATE_LEVEL'
NF_INQ_VAR_DEFLATE function will write the deflate_level here, if
deflate is in use.
Errors
======
NF_INQ_VAR_DEFLATE returns the value NF_NOERR if no errors occurred.
Otherwise, the returned status indicates an error.
Possible return codes include:
`NF_NOERR'
No error.
`NF_BADID'
Bad ncid.
`NF_ENOTNC4'
Not a netCDF-4 file.
`NF_ENOTVAR'
Can't find this variable.
Example
=======
In this example code from nf_test/ftst_vars.F, a file with a variable
using deflate is opened, and the deflate level checked.
C Is everything set that is supposed to be?
retval = nf_inq_var_deflate(ncid, varid, shuffle, deflate,
+ deflate_level)
if (retval .ne. nf_noerr) call handle_err(retval)
if (shuffle .ne. 0 .or. deflate .ne. 1 .or.
+ deflate_level .ne. 4) stop 2
6.12 Learn About Szip Parameters for a Variable: `NF_INQ_VAR_SZIP'
==================================================================
The function NF_INQ_VAR_SZIP returns the szip settings for a variable
in a netCDF-4 file.
It is not necessary to know the szip settings to read the variable.
(Szip is completely transparent to readers of the data).
Usage
=====
NF_INQ_VAR_SZIP(INTEGER NCID, INTEGER VARID, INTEGER OPTION_MASK,
PIXELS_PER_BLOCK);
`NCID'
NetCDF ID, from a previous call to NF_OPEN or NF_CREATE.
`VARID'
Variable ID.
`OPTION_MASK'
This will be set to the option_mask value.
`PIXELS_PER_BLOCK'
The number of bits per pixel will be put here.
Errors
======
NF_INQ_VAR_SZIP returns the value NF_NOERR if no errors occurred.
Otherwise, the returned status indicates an error.
Possible return codes include:
`NF_NOERR'
No error.
`NF_BADID'
Bad ncid.
`NF_ENOTNC4'
Not a netCDF-4 file.
`NF_ENOTVAR'
Can't find this variable.
Example
=======
6.13 Define Checksum Parameters for a Variable: `NF_DEF_VAR_FLETCHER32'
=======================================================================
The function NF_DEF_VAR_FLETCHER32 sets the checksum property for a
variable in a netCDF-4 file.
This function may only be called after the variable is defined, but
before NF_ENDDEF is called.
Usage
=====
NF_DEF_VAR_FLETCHER32(INTEGER NCID, INTEGER VARID, INTEGER CHECKSUM);
`NCID'
NetCDF ID, from a previous call to NF_OPEN or NF_CREATE.
`VARID'
Variable ID.
`CHECKSUM'
If this is NF_FLETCHER32, fletcher32 checksums will be turned on
for this variable.
Errors
======
NF_DEF_VAR_FLETCHER32 returns the value NF_NOERR if no errors occurred.
Otherwise, the returned status indicates an error.
Possible return codes include:
`NF_NOERR'
No error.
`NF_BADID'
Bad ncid.
`NF_ENOTNC4'
Not a netCDF-4 file.
`NF_ENOTVAR'
Can't find this variable.
`NF_ELATEDEF'
This variable has already been the subject of a NF_ENDDEF call. In
netCDF-4 files NF_ENDDEF will be called automatically for any data
read or write. Once enddef has been called, it is impossible to set
the checksum property for a variable.
`NF_ENOTINDEFINE'
Not in define mode. This is returned for netCDF classic or 64-bit
offset files, or for netCDF-4 files, when they were been created
with NF_STRICT_NC3 flag. (*note NF_CREATE::).
`NF_EPERM'
Attempt to create object in read-only file.
Example
=======
In this example from nf_test/ftst_vars.F, the variable in a file has
the Fletcher32 checksum filter turned on.
C Create the netCDF file.
retval = nf_create(FILE_NAME, NF_NETCDF4, ncid)
if (retval .ne. nf_noerr) call handle_err(retval)
C Define the dimensions.
retval = nf_def_dim(ncid, "x", NX, x_dimid)
if (retval .ne. nf_noerr) call handle_err(retval)
retval = nf_def_dim(ncid, "y", NY, y_dimid)
if (retval .ne. nf_noerr) call handle_err(retval)
C Define the variable.
dimids(1) = y_dimid
dimids(2) = x_dimid
retval = NF_DEF_VAR(ncid, "data", NF_INT, NDIMS, dimids, varid)
if (retval .ne. nf_noerr) call handle_err(retval)
C Turn on chunking.
chunks(1) = NY
chunks(2) = NX
retval = NF_DEF_VAR_CHUNKING(ncid, varid, NF_CHUNKED, chunks)
if (retval .ne. nf_noerr) call handle_err(retval)
C Turn on deflate compression, fletcher32 checksums.
retval = NF_DEF_VAR_DEFLATE(ncid, varid, 0, 1, 4)
if (retval .ne. nf_noerr) call handle_err(retval)
retval = NF_DEF_VAR_FLETCHER32(ncid, varid, NF_FLETCHER32)
if (retval .ne. nf_noerr) call handle_err(retval)
6.14 Learn About Checksum Parameters for a Variable: `NF_INQ_VAR_FLETCHER32'
============================================================================
The function NF_INQ_VAR_FLETCHER32 returns the checksum settings for a
variable in a netCDF-4 file.
Usage
=====
NF_INQ_VAR_FLETCHER32(INTEGER NCID, INTEGER VARID, INTEGER CHECKSUM);
`NCID'
NetCDF ID, from a previous call to NF_OPEN or NF_CREATE.
`VARID'
Variable ID.
`CHECKSUM'
NF_INQ_VAR_FLETCHER32 will set this to NF_FLETCHER32 if the
fletcher32 filter is turned on for this variable, and
NF_NOCHECKSUM if it is not.
Errors
======
NF_INQ_VAR_FLETCHER32 returns the value NF_NOERR if no errors occurred.
Otherwise, the returned status indicates an error.
Possible return codes include:
`NF_NOERR'
No error.
`NF_BADID'
Bad ncid.
`NF_ENOTNC4'
Not a netCDF-4 file.
`NF_ENOTVAR'
Can't find this variable.
Example
=======
In this example from nf_test/ftst_vars.F the checksum filter is checked
for a file. Since it was turned on for this variable, the checksum
variable is set to NF_FLETCHER32.
retval = nf_inq_var_fletcher32(ncid, varid, checksum)
if (retval .ne. nf_noerr) call handle_err(retval)
if (checksum .ne. NF_FLETCHER32) stop 2
6.15 Define Endianness of a Variable: `NF_DEF_VAR_ENDIAN'
=========================================================
The function NF_DEF_VAR_ENDIAN sets the endianness for a variable in a
netCDF-4 file.
This function must be called after the variable is defined, but
before NF_ENDDEF is called.
By default, netCDF-4 variables are in native endianness. That is,
they are big-endian on a big-endian machine, and little-endian on a
little endian machine.
In some cases a user might wish to change from native endianness to
either big or little-endianness. This function allows them to do that.
Usage
=====
NF_DEF_VAR_ENDIAN(INTEGER NCID, INTEGER VARID, INTEGER ENDIAN)
`NCID'
NetCDF ID, from a previous call to NF_OPEN or NF_CREATE.
`VARID'
Variable ID.
`ENDIAN'
Set to NF_ENDIAN_NATIVE for native endianness. (This is the
default). Set to NF_ENDIAN_LITTLE for little endian, or
NF_ENDIAN_BIG for big endian.
Errors
======
NF_DEF_VAR_ENDIAN returns the value NF_NOERR if no errors occurred.
Otherwise, the returned status indicates an error.
Possible return codes include:
`NF_NOERR'
No error.
`NF_BADID'
Bad ncid.
`NF_ENOTNC4'
Not a netCDF-4 file.
`NF_ENOTVAR'
Can't find this variable.
`NF_ELATEDEF'
This variable has already been the subject of a NF_ENDDEF call. In
netCDF-4 files NF_ENDDEF will be called automatically for any data
read or write. Once enddef has been called, it is impossible to set
the endianness of a variable.
`NF_ENOTINDEFINE'
Not in define mode. This is returned for netCDF classic or 64-bit
offset files, or for netCDF-4 files, when they were been created
with NF_STRICT_NC3 flag, and the file is not in define mode.
(*note NF_CREATE::).
`NF_EPERM'
Attempt to create object in read-only file.
Example
=======
In this example from nf_test/ftst_vars.c, a file is created with one
variable, and its endianness is set to NF_ENDIAN_BIG.
C Create the netCDF file.
retval = nf_create(FILE_NAME, NF_NETCDF4, ncid)
if (retval .ne. nf_noerr) call handle_err(retval)
C Define the dimensions.
retval = nf_def_dim(ncid, "x", NX, x_dimid)
if (retval .ne. nf_noerr) call handle_err(retval)
retval = nf_def_dim(ncid, "y", NY, y_dimid)
if (retval .ne. nf_noerr) call handle_err(retval)
C Define the variable.
dimids(1) = y_dimid
dimids(2) = x_dimid
retval = NF_DEF_VAR(ncid, "data", NF_INT, NDIMS, dimids, varid)
if (retval .ne. nf_noerr) call handle_err(retval)
C Turn on chunking.
chunks(1) = NY
chunks(2) = NX
retval = NF_DEF_VAR_chunking(ncid, varid, 0, chunks)
if (retval .ne. nf_noerr) call handle_err(retval)
C Set variable to big-endian (default is whatever is native to
C writing machine).
retval = NF_DEF_VAR_endian(ncid, varid, NF_ENDIAN_BIG)
if (retval .ne. nf_noerr) call handle_err(retval)
6.16 Learn About Endian Parameters for a Variable: `NF_INQ_VAR_ENDIAN'
======================================================================
The function NF_INQ_VAR_ENDIAN returns the endianness settings for a
variable in a netCDF-4 file.
Usage
=====
NF_INQ_VAR_ENDIAN(INTEGER NCID, INTEGER VARID, INTEGER ENDIAN)
`NCID'
NetCDF ID, from a previous call to NF_OPEN or NF_CREATE.
`VARID'
Variable ID.
`ENDIAN'
NF_INQ_VAR_ENDIAN will set this to NF_ENDIAN_LITTLE if this
variable is stored in little-endian format, NF_ENDIAN_BIG if it is
stored in big-endian format, and NF_ENDIAN_NATIVE if the
endianness is not set, and the variable is not created yet.
Errors
======
NF_INQ_VAR_ENDIAN returns the value NF_NOERR if no errors occurred.
Otherwise, the returned status indicates an error.
Possible return codes include:
`NF_NOERR'
No error.
`NF_BADID'
Bad ncid.
`NF_ENOTNC4'
Not a netCDF-4 file.
`NF_ENOTVAR'
Can't find this variable.
Example
=======
In this example from nf_test/ftst_vars.F, the endianness of a variable
is checked to make sure it is NF_ENDIAN_BIG.
retval = nf_inq_var_endian(ncid, varid, endianness)
if (retval .ne. nf_noerr) call handle_err(retval)
if (endianness .ne. NF_ENDIAN_BIG) stop 2
6.17 Get a Variable ID from Its Name: NF_INQ_VARID
==================================================
The function NF_INQ_VARID returns the ID of a netCDF variable, given
its name.
Usage
=====
INTEGER FUNCTION NF_INQ_VARID(INTEGER NCID, CHARACTER*(*) NAME,
INTEGER varid)
`NCID'
NetCDF ID, from a previous call to NF_OPEN or NF_CREATE.
`NAME'
Variable name for which ID is desired.
`varid'
Returned variable ID.
Errors
======
NF_INQ_VARID returns the value NF_NOERR if no errors occurred.
Otherwise, the returned status indicates an error. Possible causes of
errors include:
* The specified variable name is not a valid name for a variable in
the specified netCDF dataset.
* The specified netCDF ID does not refer to an open netCDF dataset.
Example
=======
Here is an example using NF_INQ_VARID to find out the ID of a variable
named rh in an existing netCDF dataset named foo.nc:
INCLUDE 'netcdf.inc'
...
INTEGER STATUS, NCID, RHID
...
STATUS = NF_OPEN ('foo.nc', NF_NOWRITE, NCID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
STATUS = NF_INQ_VARID (NCID, 'rh', RHID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
6.18 Get Information about a Variable from Its ID: NF_INQ_VAR family
====================================================================
A family of functions that returns information about a netCDF variable,
given its ID. Information about a variable includes its name, type,
number of dimensions, a list of dimension IDs describing the shape of
the variable, and the number of variable attributes that have been
assigned to the variable.
The function NF_INQ_VAR returns all the information about a netCDF
variable, given its ID. The other functions each return just one item
of information about a variable.
These other functions include NF_INQ_VARNAME, NF_INQ_VARTYPE,
NF_INQ_VARNDIMS, NF_INQ_VARDIMID, and NF_INQ_VARNATTS.
Usage
=====
INTEGER FUNCTION NF_INQ_VAR (INTEGER NCID, INTEGER VARID,
CHARACTER*(*) name, INTEGER xtype,
INTEGER ndims, INTEGER dimids(*),
INTEGER natts)
INTEGER FUNCTION NF_INQ_VARNAME (INTEGER NCID, INTEGER VARID,
CHARACTER*(*) name)
INTEGER FUNCTION NF_INQ_VARTYPE (INTEGER NCID, INTEGER VARID,
INTEGER xtype)
INTEGER FUNCTION NF_INQ_VARNDIMS (INTEGER NCID, INTEGER VARID,
INTEGER ndims)
INTEGER FUNCTION NF_INQ_VARDIMID (INTEGER NCID, INTEGER VARID,
INTEGER dimids(*))
INTEGER FUNCTION NF_INQ_VARNATTS (INTEGER NCID, INTEGER VARID,
INTEGER natts)
`NCID'
NetCDF ID, from a previous call to NF_OPEN or NF_CREATE.
`VARID'
Variable ID.
`NAME'
Returned variable name. The caller must allocate space for the
returned name. The maximum possible length, in characters, of a
variable name is given by the predefined constant NF_MAX_NAME.
`xtype'
Returned variable type, one of the set of predefined netCDF
external data types. The type of this parameter, NF_TYPE, is
defined in the netCDF header file. The valid netCDF external data
types are NF_BYTE, NF_CHAR, NF_SHORT, NF_INT, NF_FLOAT, AND
NF_DOUBLE.
`ndims'
Returned number of dimensions the variable was defined as using.
For example, 2 indicates a matrix, 1 indicates a vector, and 0
means the variable is a scalar with no dimensions.
`dimids'
Returned vector of *ndimsp dimension IDs corresponding to the
variable dimensions. The caller must allocate enough space for a
vector of at least *ndimsp integers to be returned. The maximum
possible number of dimensions for a variable is given by the
predefined constant NF_MAX_VAR_DIMS.
`natts'
Returned number of variable attributes assigned to this variable.
These functions return the value NF_NOERR if no errors occurred.
Otherwise, the returned status indicates an error. Possible causes of
errors include:
* The variable ID is invalid for the specified netCDF dataset.
* The specified netCDF ID does not refer to an open netCDF dataset.
Example
=======
Here is an example using NF_INQ_VAR to find out about a variable named
rh in an existing netCDF dataset named foo.nc:
INCLUDE 'netcdf.inc'
...
INTEGER STATUS, NCID
INTEGER RHID ! variable ID
CHARACTER*31 RHNAME ! variable name
INTEGER RHTYPE ! variable type
INTEGER RHN ! number of dimensions
INTEGER RHDIMS(NF_MAX_VAR_DIMS) ! variable shape
INTEGER RHNATT ! number of attributes
...
STATUS = NF_OPEN ('foo.nc', NF_NOWRITE, NCID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
STATUS = NF_INQ_VARID (NCID, 'rh', RHID) ! get ID
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
STATUS = NF_INQ_VAR (NCID, RHID, RHNAME, RHTYPE, RHN, RHDIMS, RHNATT)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
6.19 Write a Single Data Value: NF_PUT_VAR1_ type
==================================================
The functions NF_PUT_VAR1_ type put a single data value of the
specified type into a variable of an open netCDF dataset that is in
data mode. Inputs are the netCDF ID, the variable ID, an index that
specifies which value to add or alter, and the data value. The value is
converted to the external data type of the variable, if necessary.
Take care when using the simplest forms of this interface with record
variables when you don't specify how many records are to be read. If
you try to read all the values of a record variable into an array but
there are more records in the file than you assume, more data will be
read than you expect, which may cause a segmentation violation.
Usage
=====
INTEGER FUNCTION NF_PUT_VAR1_TEXT(INTEGER NCID, INTEGER VARID,
INTEGER INDEX(*), CHARACTER CHVAL)
INTEGER FUNCTION NF_PUT_VAR1_INT1(INTEGER NCID, INTEGER VARID,
INTEGER INDEX(*), INTEGER*1 I1VAL)
INTEGER FUNCTION NF_PUT_VAR1_INT2(INTEGER NCID, INTEGER VARID,
INTEGER INDEX(*), INTEGER*2 I2VAL)
INTEGER FUNCTION NF_PUT_VAR1_INT (INTEGER NCID, INTEGER VARID,
INTEGER INDEX(*), INTEGER IVAL)
INTEGER FUNCTION NF_PUT_VAR1_REAL(INTEGER NCID, INTEGER VARID,
INTEGER INDEX(*), REAL RVAL)
INTEGER FUNCTION NF_PUT_VAR1_DOUBLE(INTEGER NCID, INTEGER VARID,
INTEGER INDEX(*), DOUBLE DVAL)
INTEGER FUNCTION NF_PUT_VAR1(INTEGER NCID, INTEGER VARID,
INTEGER INDEX(*), *)
`NCID'
NetCDF ID, from a previous call to NF_OPEN or NF_CREATE.
`VARID'
Variable ID.
`INDEX'
The index of the data value to be written. The indices are relative
to 1, so for example, the first data value of a two-dimensional
variable would have index (1,1). The elements of index must
correspond to the variable's dimensions. Hence, if the variable
uses the unlimited dimension, the last index would correspond to
the record number.
`CHVAL'
`I1VAL'
`I2VAL'
`IVAL'
`RVAL'
`DVAL'
Pointer to the data value to be written. If the type of data values
differs from the netCDF variable type, type conversion will occur.
*Note Type Conversion: (netcdf)Type Conversion.
Errors
======
NF_PUT_VAR1_ type returns the value NF_NOERR if no errors occurred.
Otherwise, the returned status indicates an error. Possible causes of
errors include:
* The variable ID is invalid for the specified netCDF dataset.
* The specified indices were out of range for the rank of the
specified variable. For example, a negative index or an index that
is larger than the corresponding dimension length will cause an
error.
* The specified value is out of the range of values representable by
the external data type of the variable.
* The specified netCDF is in define mode rather than data mode.
* The specified netCDF ID does not refer to an open netCDF dataset.
Example
=======
Here is an example using NF_PUT_VAR1_DOUBLE to set the (4,3,2) element
of the variable named rh to 0.5 in an existing netCDF dataset named
foo.nc. For simplicity in this example, we assume that we know that rh
is dimensioned with lon, lat, and time, so we want to set the value of
rh that corresponds to the fourth lon value, the third lat value, and
the second time value:
INCLUDE 'netcdf.inc'
...
INTEGER STATUS ! error status
INTEGER NCID
INTEGER RHID ! variable ID
INTEGER RHINDX(3) ! where to put value
DATA RHINDX /4, 3, 2/
...
STATUS = NF_OPEN ('foo.nc', NF_WRITE, NCID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
STATUS = NF_INQ_VARID (NCID, 'rh', RHID) ! get ID
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
STATUS = NF_PUT_VAR1_DOUBLE (NCID, RHID, RHINDX, 0.5)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
6.20 Write an Entire Variable: NF_PUT_VAR_ TYPE
===============================================
The NF_PUT_VAR_ TYPE family of functions write all the values of a
variable into a netCDF variable of an open netCDF dataset. This is the
simplest interface to use for writing a value in a scalar variable or
whenever all the values of a multidimensional variable can all be
written at once. The values to be written are associated with the
netCDF variable by assuming that the last dimension of the netCDF
variable varies fastest in the C interface. The values are converted to
the external data type of the variable, if necessary.
Take care when using the simplest forms of this interface with record
variables when you don't specify how many records are to be written. If
you try to write all the values of a record variable into a netCDF file
that has no record data yet (hence has 0 records), nothing will be
written. Similarly, if you try to write all of a record variable but
there are more records in the file than you assume, more data may be
written to the file than you supply, which may result in a segmentation
violation.
Usage
=====
INTEGER FUNCTION NF_PUT_VAR_TEXT (INTEGER NCID, INTEGER VARID,
CHARACTER*(*) TEXT)
INTEGER FUNCTION NF_PUT_VAR_INT1 (INTEGER NCID, INTEGER VARID,
INTEGER*1 I1VALS(*))
INTEGER FUNCTION NF_PUT_VAR_INT2 (INTEGER NCID, INTEGER VARID,
INTEGER*2 I2VALS(*))
INTEGER FUNCTION NF_PUT_VAR_INT (INTEGER NCID, INTEGER VARID,
INTEGER IVALS(*))
INTEGER FUNCTION NF_PUT_VAR_REAL (INTEGER NCID, INTEGER VARID,
REAL RVALS(*))
INTEGER FUNCTION NF_PUT_VAR_DOUBLE(INTEGER NCID, INTEGER VARID,
DOUBLE DVALS(*))
INTEGER FUNCTION NF_PUT_VAR (INTEGER NCID, INTEGER VARID,
VALS(*))
`NCID'
NetCDF ID, from a previous call to NF_OPEN or NF_CREATE.
`VARID'
Variable ID.
`TEXT'
`I1VALS'
`I2VALS'
`IVALS'
`RVALS'
`DVALS'
`VALS'
The block of data values to be written. The data should be of the
type appropriate for the function called. You cannot put CHARACTER
data into a numeric variable or numeric data into a text variable.
For numeric data, if the type of data differs from the netCDF
variable type, type conversion will occur (*note Type Conversion:
(netcdf)Type Conversion.). The order in which the data will be
written into the specified variable is with the first dimension
varying fastest (like the ordinary FORTRAN convention).
Errors
======
Members of the NF_PUT_VAR_ TYPE family return the value NF_NOERR if no
errors occurred. Otherwise, the returned status indicates an error.
Possible causes of errors include:
* The variable ID is invalid for the specified netCDF dataset.
* One or more of the specified values are out of the range of values
representable by the external data type of the variable.
* One or more of the specified values are out of the range of values
representable by the external data type of the variable.
* The specified netCDF dataset is in define mode rather than data
mode.
* The specified netCDF ID does not refer to an open netCDF dataset.
Example
=======
Here is an example using NF_PUT_VAR_DOUBLE to add or change all the
values of the variable named rh to 0.5 in an existing netCDF dataset
named foo.nc. For simplicity in this example, we assume that we know
that rh is dimensioned with lon, lat, and time, and that there are ten
lon values, five lat values, and three time values.
INCLUDE 'netcdf.inc'
...
PARAMETER (TIMES=3, LATS=5, LONS=10) ! dimension lengths
INTEGER STATUS, NCID, TIMES
INTEGER RHID ! variable ID
DOUBLE RHVALS(LONS, LATS, TIMES)
...
STATUS = NF_OPEN ('foo.nc', NF_WRITE, NCID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
STATUS = NF_INQ_VARID (NCID, 'rh', RHID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
DO 10 ILON = 1, LONS
DO 10 ILAT = 1, LATS
DO 10 ITIME = 1, TIMES
RHVALS(ILON, ILAT, ITIME) = 0.5
10 CONTINUE
STATUS = NF_PUT_var_DOUBLE (NCID, RHID, RHVALS)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
6.21 Write an Array of Values: NF_PUT_VARA_ TYPE
================================================
The function NF_PUT_VARA_ TYPE writes values into a netCDF variable of
an open netCDF dataset. The part of the netCDF variable to write is
specified by giving a corner and a vector of edge lengths that refer to
an array section of the netCDF variable. The values to be written are
associated with the netCDF variable by assuming that the first
dimension of the netCDF variable varies fastest in the FORTRAN
interface. The netCDF dataset must be in data mode.
Usage
=====
INTEGER FUNCTION NF_PUT_VARA_TEXT(INTEGER NCID, INTEGER VARID,
INTEGER START(*), INTEGER COUNT(*),
CHARACTER*(*) TEXT)
INTEGER FUNCTION NF_PUT_VARA_INT1(INTEGER NCID, INTEGER VARID,
INTEGER START(*), INTEGER COUNT(*),
INTEGER*1 I1VALS(*))
INTEGER FUNCTION NF_PUT_VARA_INT2(INTEGER NCID, INTEGER VARID,
INTEGER START(*), INTEGER COUNT(*),
INTEGER*2 I2VALS(*))
INTEGER FUNCTION NF_PUT_VARA_INT (INTEGER NCID, INTEGER VARID,
INTEGER START(*), INTEGER COUNT(*),
INTEGER IVALS(*))
INTEGER FUNCTION NF_PUT_VARA_REAL(INTEGER NCID, INTEGER VARID,
INTEGER START(*), INTEGER COUNT(*),
REAL RVALS(*))
INTEGER FUNCTION NF_PUT_VARA_DOUBLE(INTEGER NCID, INTEGER VARID,
INTEGER START(*), INTEGER COUNT(*),
DOUBLE DVALS(*))
INTEGER FUNCTION NF_PUT_VARA (INTEGER NCID, INTEGER VARID,
INTEGER START(*), INTEGER COUNT(*),
VALS(*))
`NCID'
NetCDF ID, from a previous call to NF_OPEN or NF_CREATE.
`VARID'
Variable ID.
`START'
A vector of integers specifying the index in the variable where the
first of the data values will be written. The indices are relative
to 1, so for example, the first data value of a variable would
have index (1, 1, ..., 1). The length of START must be the same as
the number of dimensions of the specified variable. The elements
of START must correspond to the variable's dimensions in order.
Hence, if the variable is a record variable, the last index would
correspond to the starting record number for writing the data
values.
`COUNT'
A vector of integers specifying the edge lengths along each
dimension of the block of data values to written. To write a
single value, for example, specify COUNT as (1, 1, ..., 1). The
length of COUNT is the number of dimensions of the specified
variable. The elements of COUNT correspond to the variable's
dimensions. Hence, if the variable is a record variable, the last
element of COUNT corresponds to a count of the number of records
to write.
Note: setting any element of the count array to zero causes the
function to exit without error, and without doing anything.
`TEXT'
`I1VALS'
`I2VALS'
`IVALS'
`RVALS'
`DVALS'
`VALS'
The block of data values to be written. The data should be of the
type appropriate for the function called. You cannot put CHARACTER
data into a numeric variable or numeric data into a text variable.
For numeric data, if the type of data differs from the netCDF
variable type, type conversion will occur (*note Type Conversion:
(netcdf)Type Conversion.).
Errors
======
NF_PUT_VARA_ TYPE returns the value NF_NOERR if no errors occurred.
Otherwise, the returned status indicates an error. Possible causes of
errors include:
* The variable ID is invalid for the specified netCDF dataset.
* The specified corner indices were out of range for the rank of the
specified variable. For example, a negative index, or an index
that is larger than the corresponding dimension length will cause
an error.
* The specified edge lengths added to the specified corner would have
referenced data out of range for the rank of the specified
variable. For example, an edge length that is larger than the
corresponding dimension length minus the corner index will cause an
error.
* One or more of the specified values are out of the range of values
representable by the external data type of the variable.
* The specified netCDF dataset is in define mode rather than data
mode.
* The specified netCDF ID does not refer to an open netCDF dataset.
Example
=======
Here is an example using NF_PUT_VARA_DOUBLE to add or change all the
values of the variable named rh to 0.5 in an existing netCDF dataset
named foo.nc. For simplicity in this example, we assume that we know
that rh is dimensioned with time, lat, and lon, and that there are
three time values, five lat values, and ten lon values.
INCLUDE 'netcdf.inc'
...
PARAMETER (NDIMS=3) ! number of dimensions
PARAMETER (TIMES=3, LATS=5, LONS=10) ! dimension lengths
INTEGER STATUS, NCID, TIMES
INTEGER RHID ! variable ID
INTEGER START(NDIMS), COUNT(NDIMS)
DOUBLE RHVALS(LONS, LATS, TIMES)
DATA START /1, 1, 1/ ! start at first value
DATA COUNT /LONS, LATS, TIMES/
...
STATUS = NF_OPEN ('foo.nc', NF_WRITE, NCID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
STATUS = NF_INQ_VARID (NCID, 'rh', RHID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
DO 10 ILON = 1, LONS
DO 10 ILAT = 1, LATS
DO 10 ITIME = 1, TIMES
RHVALS(ILON, ILAT, ITIME) = 0.5
10 CONTINUE
STATUS = NF_PUT_VARA_DOUBLE (NCID, RHID, START, COUNT, RHVALS)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
6.22 NF_PUT_VARS_ TYPE
======================
Each member of the family of functions NF_PUT_VARS_ TYPE writes a
subsampled (strided) array section of values into a netCDF variable of
an open netCDF dataset. The subsampled array section is specified by
giving a corner, a vector of counts, and a stride vector. The netCDF
dataset must be in data mode.
Usage
=====
INTEGER FUNCTION NF_PUT_VARS_TEXT (INTEGER NCID, INTEGER VARID,
INTEGER START(*), INTEGER COUNT(*),
INTEGER STRIDE(*),CHARACTER*(*) TEXT)
INTEGER FUNCTION NF_PUT_VARS_INT1 (INTEGER NCID, INTEGER VARID,
INTEGER START(*), INTEGER COUNT(*),
INTEGER STRIDE(*),INTEGER*1 I1VALS(*))
INTEGER FUNCTION NF_PUT_VARS_INT2 (INTEGER NCID, INTEGER VARID,
INTEGER START(*), INTEGER COUNT(*),
INTEGER STRIDE(*),INTEGER*2 I2VALS(*))
INTEGER FUNCTION NF_PUT_VARS_INT (INTEGER NCID, INTEGER VARID,
INTEGER START(*), INTEGER COUNT(*),
INTEGER STRIDE(*), INTEGER IVALS(*))
INTEGER FUNCTION NF_PUT_VARS_REAL (INTEGER NCID, INTEGER VARID,
INTEGER START(*), INTEGER COUNT(*),
INTEGER STRIDE(*), REAL RVALS(*))
INTEGER FUNCTION NF_PUT_VARS_DOUBLE(INTEGER NCID, INTEGER VARID,
INTEGER START(*), INTEGER COUNT(*),
INTEGER STRIDE(*), DOUBLE DVALS(*))
INTEGER FUNCTION NF_PUT_VARS (INTEGER NCID, INTEGER VARID,
INTEGER START(*), INTEGER COUNT(*),
INTEGER STRIDE(*), VALS(*))
`NCID'
NetCDF ID, from a previous call to NF_OPEN or NF_CREATE.
`VARID'
Variable ID.
`START'
A vector of integers specifying the index in the variable where the
first of the data values will be written. The indices are relative
to 1, so for example, the first data value of a variable would
have index (1, 1, ..., 1). The elements of START correspond, in
order, to the variable's dimensions. Hence, if the variable is a
record variable, the last index would correspond to the starting
record number for writing the data values.
`COUNT'
A vector of integers specifying the number of indices selected
along each dimension. To write a single value, for example,
specify COUNT as (1, 1, ..., 1). The elements of COUNT correspond,
in order, to the variable's dimensions. Hence, if the variable is
a record variable, the last element of COUNT corresponds to a
count of the number of records to write.
Note: setting any element of the count array to zero causes the
function to exit without error, and without doing anything.
`STRIDE'
A vector of integers that specifies the sampling interval along
each dimension of the netCDF variable. The elements of the stride
vector correspond, in order, to the netCDF variable's dimensions
(STRIDE(1) gives the sampling interval along the most rapidly
varying dimension of the netCDF variable). Sampling intervals are
specified in type-independent units of elements (a value of 1
selects consecutive elements of the netCDF variable along the
corresponding dimension, a value of 2 selects every other element,
etc.).
`TEXT'
`I1VALS'
`I2VALS'
`IVALS'
`RVALS'
`DVALS'
`VALS'
The block of data values to be written. The data should be of the
type appropriate for the function called. You cannot put CHARACTER
data into a numeric variable or numeric data into a text variable.
For numeric data, if the type of data differs from the netCDF
variable type, type conversion will occur (*note Type Conversion:
(netcdf)Type Conversion.).
Errors
======
NF_PUT_VARS_ TYPE returns the value NF_NOERR if no errors occurred.
Otherwise, the returned status indicates an error. Possible causes of
errors include:
* The variable ID is invalid for the specified netCDF dataset.
* The specified start, count and stride generate an index which is
out of range.
* One or more of the specified values are out of the range of values
representable by the external data type of the variable.
* The specified netCDF is in define mode rather than data mode.
* The specified netCDF ID does not refer to an open netCDF dataset.
Example
=======
Here is an example of using NF_PUT_VARS_REAL to write - from an
internal array - every other point of a netCDF variable named rh which
is described by the FORTRAN declaration REAL RH(6,4) (note the size of
the dimensions):
INCLUDE 'netcdf.inc'
...
PARAMETER (NDIM=2) ! rank of netCDF variable
INTEGER NCID ! netCDF dataset ID
INTEGER STATUS ! return code
INTEGER RHID ! variable ID
INTEGER START(NDIM) ! netCDF variable start point
INTEGER COUNT(NDIM) ! size of internal array
INTEGER STRIDE(NDIM) ! netCDF variable subsampling intervals
REAL RH(3,2) ! note subsampled sizes for netCDF variable
! dimensions
DATA START /1, 1/ ! start at first netCDF variable value
DATA COUNT /3, 2/ ! size of internal array: entire (subsampled)
! netCDF variable
DATA STRIDE /2, 2/ ! access every other netCDF element
...
STATUS = NF_OPEN('foo.nc', NF_WRITE, NCID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
STATUS = NF_INQ_VARID(NCID, 'rh', RHID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
STATUS = NF_PUT_VARS_REAL(NCID, RHID, START, COUNT, STRIDE, RH)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
6.23 NF_PUT_VARM_ TYPE
======================
The NF_PUT_VARM_ TYPE family of functions writes a mapped array section
of values into a netCDF variable of an open netCDF dataset. The mapped
array section is specified by giving a corner, a vector of counts, a
stride vector, and an index mapping vector. The index mapping vector is
a vector of integers that specifies the mapping between the dimensions
of a netCDF variable and the in-memory structure of the internal data
array. No assumptions are made about the ordering or length of the
dimensions of the data array. The netCDF dataset must be in data mode.
Usage
=====
INTEGER FUNCTION NF_PUT_VARM_TEXT (INTEGER NCID, INTEGER VARID,
INTEGER START(*), INTEGER COUNT(*),
INTEGER STRIDE(*), INTEGER IMAP(*),
CHARACTER*(*) TEXT)
INTEGER FUNCTION NF_PUT_VARM_INT1 (INTEGER NCID, INTEGER VARID,
INTEGER START(*), INTEGER COUNT(*),
INTEGER STRIDE(*), INTEGER IMAP(*),
INTEGER*1 I1VALS(*))
INTEGER FUNCTION NF_PUT_VARM_INT2 (INTEGER NCID, INTEGER VARID,
INTEGER START(*), INTEGER COUNT(*),
INTEGER STRIDE(*), INTEGER IMAP(*),
INTEGER*2 I2VALS(*))
INTEGER FUNCTION NF_PUT_VARM_INT (INTEGER NCID, INTEGER VARID,
INTEGER START(*), INTEGER COUNT(*),
INTEGER STRIDE(*), INTEGER IMAP(*),
INTEGER IVALS(*))
INTEGER FUNCTION NF_PUT_VARM_REAL (INTEGER NCID, INTEGER VARID,
INTEGER START(*), INTEGER COUNT(*),
INTEGER STRIDE(*), INTEGER IMAP(*),
REAL RVALS(*))
INTEGER FUNCTION NF_PUT_VARM_DOUBLE(INTEGER NCID, INTEGER VARID,
INTEGER START(*), INTEGER COUNT(*),
INTEGER STRIDE(*), INTEGER IMAP(*),
DOUBLE DVALS(*))
`NCID'
NetCDF ID, from a previous call to NF_OPEN or NF_CREATE.
`VARID'
Variable ID.
`START'
A vector of integers specifying the index in the variable where the
first of the data values will be written. The indices are relative
to 1, so for example, the first data value of a variable would
have index (1, 1, ..., 1). The elements of START correspond, in
order, to the variable's dimensions. Hence, if the variable is a
record variable, the last index would correspond to the starting
record number for writing the data values.
`COUNT'
A vector of integers specifying the number of indices selected
along each dimension. To write a single value, for example,
specify COUNT as (1, 1, ..., 1). The elements of COUNT correspond,
in order, to the variable's dimensions. Hence, if the variable is
a record variable, the last element of COUNT corresponds to a
count of the number of records to write.
Note: setting any element of the count array to zero causes the
function to exit without error, and without doing anything.
`STRIDE'
A vector of integers that specifies the sampling interval along
each dimension of the netCDF variable. The elements of the stride
vector correspond, in order, to the netCDF variable's dimensions
(STRIDE(1) gives the sampling interval along the most rapidly
varying dimension of the netCDF variable). Sampling intervals are
specified in type-independent units of elements (a value of 1
selects consecutive elements of the netCDF variable along the
corresponding dimension, a value of 2 selects every other element,
etc.).
`IMAP'
A vector of integers that specifies the mapping between the
dimensions of a netCDF variable and the in-memory structure of the
internal data array. The elements of the index mapping vector
correspond, in order, to the netCDF variable's dimensions (IMAP(1)
gives the distance between elements of the internal array
corresponding to the most rapidly varying dimension of the netCDF
variable). Distances between elements are specified in units of
elements (the distance between internal elements that occupy
adjacent memory locations is 1 and not the element's byte-length
as in netCDF 2).
`TEXT'
`I1VALS'
`I2VALS'
`IVALS'
`RVALS'
`DVALS'
The data values to be written. The data should be of the type
appropriate for the function called. You cannot put CHARACTER data
into a numeric variable or numeric data into a text variable. For
numeric data, if the type of data differs from the netCDF variable
type, type conversion will occur (*note Type Conversion:
(netcdf)Type Conversion.).
Errors
======
NF_PUT_VARM_ TYPE returns the value NF_NOERR if no errors occurred.
Otherwise, the returned status indicates an error. Possible causes of
errors include:
* The variable ID is invalid for the specified netCDF dataset.
* The specified START, COUNT, and STRIDE generate an index which is
out of range. Note that no error checking is possible on the imap
vector.
* One or more of the specified values are out of the range of values
representable by the external data type of the variable.
* The specified netCDF is in define mode rather than data mode.
* The specified netCDF ID does not refer to an open netCDF dataset.
Example
=======
The following IMAP vector maps in the trivial way a 2x3x4 netCDF
variable and an internal array of the same shape:
REAL A(2,3,4) ! same shape as netCDF variable
INTEGER IMAP(3)
DATA IMAP /1, 2, 6/ ! netCDF dimension inter-element distance
! ---------------- ----------------------
! most rapidly varying 1
! intermediate 2 (=IMAP(1)*2)
! most slowly varying 6 (=IMAP(2)*3)
Using the IMAP vector above with NF_PUT_VARM_REAL obtains the same
result as simply using NF_PUT_VAR_REAL.
Here is an example of using NF_PUT_VARM_REAL to write - from a
transposed, internal array - a netCDF variable named rh which is
described by the FORTRAN declaration REAL RH(4,6) (note the size and
order of the dimensions):
INCLUDE 'netcdf.inc'
...
PARAMETER (NDIM=2) ! rank of netCDF variable
INTEGER NCID ! netCDF ID
INTEGER STATUS ! return code
INTEGER RHID ! variable ID
INTEGER START(NDIM) ! netCDF variable start point
INTEGER COUNT(NDIM) ! size of internal array
INTEGER STRIDE(NDIM) ! netCDF variable subsampling intervals
INTEGER IMAP(NDIM) ! internal array inter-element distances
REAL RH(6,4) ! note transposition of netCDF variable dimensions
DATA START /1, 1/ ! start at first netCDF variable element
DATA COUNT /4, 6/ ! entire netCDF variable; order corresponds
! to netCDF variable -- not internal array
DATA STRIDE /1, 1/ ! sample every netCDF element
DATA IMAP /6, 1/ ! would be /1, 4/ if not transposing
STATUS = NF_OPEN('foo.nc', NF_WRITE, NCID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
STATUS = NF_INQ_VARID(NCID, 'rh', RHID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
STATUS = NF_PUT_VARM_REAL(NCID, RHID, START, COUNT, STRIDE, IMAP, RH)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
Here is another example of using NF_PUT_VARM_REAL to write - from a
transposed, internal array - a subsample of the same netCDF variable,
by writing every other point of the netCDF variable:
INCLUDE 'netcdf.inc'
...
PARAMETER (NDIM=2) ! rank of netCDF variable
INTEGER NCID ! netCDF dataset ID
INTEGER STATUS ! return code
INTEGER RHID ! variable ID
INTEGER START(NDIM) ! netCDF variable start point
INTEGER COUNT(NDIM) ! size of internal array
INTEGER STRIDE(NDIM) ! netCDF variable subsampling intervals
INTEGER IMAP(NDIM) ! internal array inter-element distances
REAL RH(3,2) ! note transposition of (subsampled) dimensions
DATA START /1, 1/ ! start at first netCDF variable value
DATA COUNT /2, 3/ ! order of (subsampled) dimensions corresponds
! to netCDF variable -- not internal array
DATA STRIDE /2, 2/ ! sample every other netCDF element
DATA IMAP /3, 1/ ! would be `1, 2' if not transposing
...
STATUS = NF_OPEN('foo.nc', NF_WRITE, NCID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
STATUS = NF_INQ_VARID(NCID, 'rh', RHID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
STATUS = NF_PUT_VARM_REAL(NCID, RHID, START, COUNT, STRIDE, IMAP, RH)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
6.24 NF_GET_VAR1_ TYPE
======================
The functions NF_GET_VAR1_ TYPE get a single data value from a variable
of an open netCDF dataset that is in data mode. Inputs are the netCDF
ID, the variable ID, a multidimensional index that specifies which
value to get, and the address of a location into which the data value
will be read. The value is converted from the external data type of the
variable, if necessary.
Usage
=====
INTEGER FUNCTION NF_GET_VAR1_TEXT(INTEGER NCID, INTEGER VARID,
INTEGER INDEX(*), CHARACTER CHVAL)
INTEGER FUNCTION NF_GET_VAR1_INT1(INTEGER NCID, INTEGER VARID,
INTEGER INDEX(*), INTEGER*1 I1VAL)
INTEGER FUNCTION NF_GET_VAR1_INT2(INTEGER NCID, INTEGER VARID,
INTEGER INDEX(*), INTEGER*2 I2VAL)
INTEGER FUNCTION NF_GET_VAR1_INT (INTEGER NCID, INTEGER VARID,
INTEGER INDEX(*), INTEGER IVAL)
INTEGER FUNCTION NF_GET_VAR1_REAL(INTEGER NCID, INTEGER VARID,
INTEGER INDEX(*), REAL RVAL)
INTEGER FUNCTION NF_GET_VAR1_DOUBLE(INTEGER NCID, INTEGER VARID,
INTEGER INDEX(*), DOUBLE DVAL)
INTEGER FUNCTION NF_GET_VAR1(INTEGER NCID, INTEGER VARID,
INTEGER INDEX(*), VAL)
`NCID'
NetCDF ID, from a previous call to NF_OPEN or NF_CREATE.
`VARID'
Variable ID.
`INDEX'
The index of the data value to be read. The indices are relative
to 1, so for example, the first data value of a two-dimensional
variable has index (1,1). The elements of index correspond to the
variable's dimensions. Hence, if the variable is a record
variable, the last index is the record number.
`CHVAL'
`I1VAL'
`I2VAL'
`IVAL'
`RVAL'
`DVAL'
`VAL'
The location into which the data value will be read. You cannot get
CHARACTER data from a numeric variable or numeric data from a
character variable. For numeric data, if the type of data differs
from the netCDF variable type, type conversion will occur. (*note
Type Conversion: (netcdf)Type Conversion.).
Errors
======
NF_GET_VAR1_ TYPE returns the value NF_NOERR if no errors occurred.
Otherwise, the returned status indicates an error. Possible causes of
errors include:
* The variable ID is invalid for the specified netCDF dataset.
* The specified indices were out of range for the rank of the
specified variable. For example, a negative index or an index that
is larger than the corresponding dimension length will cause an
error.
* The value is out of the range of values representable by the
desired data type.
* The specified netCDF is in define mode rather than data mode.
* The specified netCDF ID does not refer to an open netCDF dataset.
Example
=======
Here is an example using NF_GET_VAR1_DOUBLE to get the (4,3,2) element
of the variable named rh in an existing netCDF dataset named foo.nc.
For simplicity in this example, we assume that we know that rh is
dimensioned with lon, lat, and time, so we want to get the value of rh
that corresponds to the fourth lon value, the third lat value, and the
second time value:
INCLUDE 'netcdf.inc'
...
INTEGER STATUS, NCID
INTEGER RHID ! variable ID
INTEGER RHINDX(3) ! where to get value
DOUBLE PRECISION RHVAL ! put it here
DATA RHINDX /4, 3, 2/
...
STATUS = NF_OPEN ('foo.nc', NF_NOWRITE, NCID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
STATUS = NF_INQ_VARID (NCID, 'rh', RHID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
STATUS = NF_GET_VAR1_DOUBLE (NCID, RHID, RHINDX, RHVAL)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
6.25 NF_GET_VAR_ TYPE
=====================
The members of the NF_GET_VAR_ TYPE family of functions read all the
values from a netCDF variable of an open netCDF dataset. This is the
simplest interface to use for reading the value of a scalar variable or
when all the values of a multidimensional variable can be read at once.
The values are read into consecutive locations with the first dimension
varying fastest. The netCDF dataset must be in data mode.
Take care when using the simplest forms of this interface with
record variables when you don't specify how many records are to be
read. If you try to read all the values of a record variable into an
array but there are more records in the file than you assume, more data
will be read than you expect, which may cause a segmentation violation.
Usage
=====
INTEGER FUNCTION NF_GET_VAR_TEXT (INTEGER NCID, INTEGER VARID,
CHARACTER*(*) text)
INTEGER FUNCTION NF_GET_VAR_INT1 (INTEGER NCID, INTEGER VARID,
INTEGER*1 i1vals(*))
INTEGER FUNCTION NF_GET_VAR_INT2 (INTEGER NCID, INTEGER VARID,
INTEGER*2 i2vals(*))
INTEGER FUNCTION NF_GET_VAR_INT (INTEGER NCID, INTEGER VARID,
INTEGER ivals(*))
INTEGER FUNCTION NF_GET_VAR_REAL (INTEGER NCID, INTEGER VARID,
REAL rvals(*))
INTEGER FUNCTION NF_GET_VAR_DOUBLE(INTEGER NCID, INTEGER VARID,
DOUBLE dvals(*))
INTEGER FUNCTION NF_GET_VAR (INTEGER NCID, INTEGER VARID,
vals(*))
`NCID'
NetCDF ID, from a previous call to NF_OPEN or NF_CREATE.
`VARID'
Variable ID.
`TEXT'
`I1VALS'
`I2VALS'
`IVALS'
`RVALS'
`DVALS'
`VALS'
The block of data values to be read. The data should be of the type
appropriate for the function called. You cannot read CHARACTER data
from a numeric variable or numeric data from a text variable. For
numeric data, if the type of data differs from the netCDF variable
type, type conversion will occur (*note Type Conversion:
(netcdf)Type Conversion.).
Errors
======
NF_GET_VAR_ TYPE returns the value NF_NOERR if no errors occurred.
Otherwise, the returned status indicates an error. Possible causes of
errors include:
* The variable ID is invalid for the specified netCDF dataset.
* One or more of the values are out of the range of values
representable by the desired type.
* The specified netCDF is in define mode rather than data mode.
* The specified netCDF ID does not refer to an open netCDF dataset.
Example
=======
Here is an example using NF_GET_VAR_DOUBLE to read all the values of
the variable named rh from an existing netCDF dataset named foo.nc. For
simplicity in this example, we assume that we know that rh is
dimensioned with lon, lat, and time, and that there are ten lon values,
five lat values, and three time values.
INCLUDE 'netcdf.inc'
...
PARAMETER (TIMES=3, LATS=5, LONS=10) ! dimension lengths
INTEGER STATUS, NCID
INTEGER RHID ! variable ID
DOUBLE RHVALS(LONS, LATS, TIMES)
...
STATUS = NF_OPEN ('foo.nc', NF_NOWRITE, NCID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
STATUS = NF_INQ_VARID (NCID, 'rh', RHID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
STATUS = NF_GET_VAR_DOUBLE (NCID, RHID, RHVALS)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
6.26 NF_GET_VARA_ TYPE
======================
The members of the NF_GET_VARA_ TYPE family of functions read an array
of values from a netCDF variable of an open netCDF dataset. The array
is specified by giving a corner and a vector of edge lengths. The
values are read into consecutive locations with the first dimension
varying fastest. The netCDF dataset must be in data mode.
Usage
=====
INTEGER FUNCTION NF_GET_VARA_TEXT(INTEGER NCID, INTEGER VARID,
INTEGER START(*), INTEGER COUNT(*),
CHARACTER*(*) text)
INTEGER FUNCTION NF_GET_VARA_INT1(INTEGER NCID, INTEGER VARID,
INTEGER START(*), INTEGER COUNT(*),
INTEGER*1 i1vals(*))
INTEGER FUNCTION NF_GET_VARA_INT2(INTEGER NCID, INTEGER VARID,
INTEGER START(*), INTEGER COUNT(*),
INTEGER*2 i2vals(*))
INTEGER FUNCTION NF_GET_VARA_INT (INTEGER NCID, INTEGER VARID,
INTEGER START(*), INTEGER COUNT(*),
INTEGER ivals(*))
INTEGER FUNCTION NF_GET_VARA_REAL(INTEGER NCID, INTEGER VARID,
INTEGER START(*), INTEGER COUNT(*),
REAL rvals(*))
INTEGER FUNCTION NF_GET_VARA_DOUBLE(INTEGER NCID, INTEGER VARID,
INTEGER START(*), INTEGER COUNT(*),
DOUBLE dvals(*))
`NCID'
NetCDF ID, from a previous call to NF_OPEN or NF_CREATE.
`VARID'
Variable ID.
`START'
A vector of integers specifying the index in the variable where the
first of the data values will be read. The indices are relative to
1, so for example, the first data value of a variable would have
index (1, 1, ..., 1). The length of START must be the same as the
number of dimensions of the specified variable. The elements of
START correspond, in order, to the variable's dimensions. Hence,
if the variable is a record variable, the last index would
correspond to the starting record number for reading the data
values.
`COUNT'
A vector of integers specifying the edge lengths along each
dimension of the block of data values to be read. To read a single
value, for example, specify COUNT as (1, 1, ..., 1). The length of
COUNT is the number of dimensions of the specified variable. The
elements of COUNT correspond, in order, to the variable's
dimensions. Hence, if the variable is a record variable, the last
element of COUNT corresponds to a count of the number of records
to read.
Note: setting any element of the count array to zero causes the
function to exit without error, and without doing anything.
`text'
`i1vals'
`i2vals'
`ivals'
`rvals'
`dvals'
The block of data values to be read. The data should be of the type
appropriate for the function called. You cannot read CHARACTER data
from a numeric variable or numeric data from a text variable. For
numeric data, if the type of data differs from the netCDF variable
type, type conversion will occur (*note Type Conversion:
(netcdf)Type Conversion.).
Errors
======
NF_GET_VARA_ TYPE returns the value NF_NOERR if no errors occurred.
Otherwise, the returned status indicates an error. Possible causes of
errors include:
* The variable ID is invalid for the specified netCDF dataset.
* The specified corner indices were out of range for the rank of the
specified variable. For example, a negative index or an index that
is larger than the corresponding dimension length will cause an
error.
* The specified edge lengths added to the specified corner would have
referenced data out of range for the rank of the specified
variable. For example, an edge length that is larger than the
corresponding dimension length minus the corner index will cause an
error.
* One or more of the values are out of the range of values
representable by the desired type.
* The specified netCDF is in define mode rather than data mode.
* The specified netCDF ID does not refer to an open netCDF dataset.
Example
=======
Here is an example using NF_GET_VARA_DOUBLE to read all the values of
the variable named rh from an existing netCDF dataset named foo.nc. For
simplicity in this example, we assume that we know that rh is
dimensioned with lon, lat, and time, and that there are ten lon values,
five lat values, and three time values.
INCLUDE 'netcdf.inc'
...
PARAMETER (NDIMS=3) ! number of dimensions
PARAMETER (TIMES=3, LATS=5, LONS=10) ! dimension lengths
INTEGER STATUS, NCID
INTEGER RHID ! variable ID
INTEGER START(NDIMS), COUNT(NDIMS)
DOUBLE RHVALS(LONS, LATS, TIMES)
DATA START /1, 1, 1/ ! start at first value
DATA COUNT /LONS, LATS, TIMES/ ! get all the values
...
STATUS = NF_OPEN ('foo.nc', NF_NOWRITE, NCID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
STATUS = NF_INQ_VARID (NCID, 'rh', RHID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
STATUS = NF_GET_VARA_DOUBLE (NCID, RHID, START, COUNT, RHVALS)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
6.27 NF_GET_VARS_ TYPE
======================
The NF_GET_VARS_ TYPE family of functions read a subsampled (strided)
array section of values from a netCDF variable of an open netCDF
dataset. The subsampled array section is specified by giving a corner,
a vector of edge lengths, and a stride vector. The values are read with
the first dimension of the netCDF variable varying fastest. The netCDF
dataset must be in data mode.
Usage
=====
INTEGER FUNCTION NF_GET_VARS_TEXT (INTEGER NCID, INTEGER VARID,
INTEGER START(*), INTEGER COUNT(*),
INTEGER STRIDE(*),CHARACTER*(*) text)
INTEGER FUNCTION NF_GET_VARS_INT1 (INTEGER NCID, INTEGER VARID,
INTEGER START(*), INTEGER COUNT(*),
INTEGER STRIDE(*),INTEGER*1 i1vals(*))
INTEGER FUNCTION NF_GET_VARS_INT2 (INTEGER NCID, INTEGER VARID,
INTEGER START(*), INTEGER COUNT(*),
INTEGER STRIDE(*),INTEGER*2 i2vals(*))
INTEGER FUNCTION NF_GET_VARS_INT (INTEGER NCID, INTEGER VARID,
INTEGER START(*), INTEGER COUNT(*),
INTEGER STRIDE(*), INTEGER ivals(*))
INTEGER FUNCTION NF_GET_VARS_REAL (INTEGER NCID, INTEGER VARID,
INTEGER START(*), INTEGER COUNT(*),
INTEGER STRIDE(*), REAL rvals(*))
INTEGER FUNCTION NF_GET_VARS_DOUBLE(INTEGER NCID, INTEGER VARID,
INTEGER START(*), INTEGER COUNT(*),
INTEGER STRIDE(*), DOUBLE dvals(*))
`NCID'
NetCDF ID, from a previous call to NF_OPEN or NF_CREATE.
`VARID'
Variable ID.
`START'
A vector of integers specifying the index in the variable from
which the first of the data values will be read. The indices are
relative to 1, so for example, the first data value of a variable
would have index (1, 1, ..., 1). The elements of START correspond,
in order, to the variable's dimensions. Hence, if the variable is
a record variable, the last index would correspond to the starting
record number for reading the data values.
`COUNT'
A vector of integers specifying the number of indices selected
along each dimension. To read a single value, for example, specify
COUNT as (1, 1, ..., 1). The elements of COUNT correspond, in
order, to the variable's dimensions. Hence, if the variable is a
record variable, the last element of COUNT corresponds to a count
of the number of records to read.
Note: setting any element of the count array to zero causes the
function to exit without error, and without doing anything.
`STRIDE'
A vector of integers specifying, for each dimension, the interval
between selected indices or the value 0. The elements of the vector
correspond, in order, to the variable's dimensions. A value of 1
accesses adjacent values of the netCDF variable in the
corresponding dimension; a value of 2 accesses every other value
of the netCDF variable in the corresponding dimension; and so on.
A 0 argument is treated as (1, 1, ..., 1).
`text'
`i1vals'
`i2vals'
`ivals'
`rvals'
`dvals'
The block of data values to be read. The data should be of the type
appropriate for the function called. You cannot read CHARACTER data
from a numeric variable or numeric data from a text variable. For
numeric data, if the type of data differs from the netCDF variable
type, type conversion will occur (*note Type Conversion:
(netcdf)Type Conversion.).
Errors
======
NF_GET_VARS_ TYPE returns the value NF_NOERR if no errors occurred.
Otherwise, the returned status indicates an error. Possible causes of
errors include:
* The variable ID is invalid for the specified netCDF dataset.
* The specified start, count and stride generate an index which is
out of range.
* One or more of the values are out of the range of values
representable by the desired type.
* The specified netCDF is in define mode rather than data mode.
* The specified netCDF ID does not refer to an open netCDF dataset.
Example
=======
Here is an example using NF_GET_VARS_DOUBLE to read every other value
in each dimension of the variable named rh from an existing netCDF
dataset named foo.nc. Values are assigned, using the same dimensional
strides, to a 2-parameter array. For simplicity in this example, we
assume that we know that rh is dimensioned with lon, lat, and time, and
that there are ten lon values, five lat values, and three time values.
INCLUDE 'netcdf.inc'
...
PARAMETER (NDIMS=3) ! number of dimensions
PARAMETER (TIMES=3, LATS=5, LONS=10) ! dimension lengths
INTEGER STATUS, NCID
INTEGER RHID ! variable ID
INTEGER START(NDIMS), COUNT(NDIMS), STRIDE(NDIMS)
DOUBLE DATA(LONS, LATS, TIMES)
DATA START /1, 1, 1/ ! start at first value
DATA COUNT /LONS, LATS, TIMES/
DATA STRIDE /2, 2, 2/
...
STATUS = NF_OPEN ('foo.nc', NF_NOWRITE, NCID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
STATUS = NF_INQ_VARID (NCID, 'rh', RHID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
STATUS = NF_GET_VARS_DOUBLE(NCID,RHID,START,COUNT,STRIDE,DATA(1,1,1))
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
6.28 NF_GET_VARM_ TYPE
======================
The NF_GET_VARM_ TYPE family of functions reads a mapped array section
of values from a netCDF variable of an open netCDF dataset. The mapped
array section is specified by giving a corner, a vector of edge
lengths, a stride vector, and an index mapping vector. The index
mapping vector is a vector of integers that specifies the mapping
between the dimensions of a netCDF variable and the in-memory structure
of the internal data array. No assumptions are made about the ordering
or length of the dimensions of the data array. The netCDF dataset must
be in data mode.
Usage
=====
INTEGER FUNCTION NF_GET_VARM_TEXT (INTEGER NCID, INTEGER VARID,
INTEGER START(*), INTEGER COUNT(*),
INTEGER STRIDE(*), INTEGER IMAP(*),
CHARACTER*(*) text)
INTEGER FUNCTION NF_GET_VARM_INT1 (INTEGER NCID, INTEGER VARID,
INTEGER START(*), INTEGER COUNT(*),
INTEGER STRIDE(*), INTEGER IMAP(*),
INTEGER*1 i1vals(*))
INTEGER FUNCTION NF_GET_VARM_INT2 (INTEGER NCID, INTEGER VARID,
INTEGER START(*), INTEGER COUNT(*),
INTEGER STRIDE(*), INTEGER IMAP(*),
INTEGER*2 i2vals(*))
INTEGER FUNCTION NF_GET_VARM_INT (INTEGER NCID, INTEGER VARID,
INTEGER START(*), INTEGER COUNT(*),
INTEGER STRIDE(*), INTEGER IMAP(*),
INTEGER ivals(*))
INTEGER FUNCTION NF_GET_VARM_REAL (INTEGER NCID, INTEGER VARID,
INTEGER START(*), INTEGER COUNT(*),
INTEGER STRIDE(*), INTEGER IMAP(*),
REAL rvals(*))
INTEGER FUNCTION NF_GET_VARM_DOUBLE(INTEGER NCID, INTEGER VARID,
INTEGER START(*), INTEGER COUNT(*),
INTEGER STRIDE(*), INTEGER IMAP(*),
DOUBLE dvals(*))
`NCID'
NetCDF ID, from a previous call to NF_OPEN or NF_CREATE.
`VARID'
Variable ID.
`START'
A vector of integers specifying the index in the variable from
which the first of the data values will be read. The indices are
relative to 1, so for example, the first data value of a variable
would have index (1, 1, ..., 1). The elements of START correspond,
in order, to the variable's dimensions. Hence, if the variable is
a record variable, the last index would correspond to the starting
record number for reading the data values.
`COUNT'
A vector of integers specifying the number of indices selected
along each dimension. To read a single value, for example, specify
COUNT as (1, 1, ..., 1). The elements of COUNT correspond, in
order, to the variable's dimensions. Hence, if the variable is a
record variable, the last element of COUNT corresponds to a count
of the number of records to read.
Note: setting any element of the count array to zero causes the
function to exit without error, and without doing anything.
`STRIDE'
A vector of integers specifying, for each dimension, the interval
between selected indices or the value 0. The elements of the vector
correspond, in order, to the variable's dimensions. A value of 1
accesses adjacent values of the netCDF variable in the
corresponding dimension; a value of 2 accesses every other value
of the netCDF variable in the corresponding dimension; and so on.
A 0 argument is treated as (1, 1, ..., 1).
`IMAP'
A vector of integers that specifies the mapping between the
dimensions of a netCDF variable and the in-memory structure of the
internal data array. IMAP(1) gives the distance between elements
of the internal array corresponding to the most rapidly varying
dimension of the netCDF variable. IMAP(N) (where N is the rank of
the netCDF variable) gives the distance between elements of the
internal array corresponding to the most slowly varying dimension
of the netCDF variable. Intervening IMAP elements correspond to
other dimensions of the netCDF variable in the obvious way.
Distances between elements are specified in units of elements (the
distance between internal elements that occupy adjacent memory
locations is 1 and not the element's byte-length as in netCDF 2).
`text'
`i1vals'
`i2vals'
`ivals'
`rvals'
`dvals'
The block of data values to be read. The data should be of the type
appropriate for the function called. You cannot read CHARACTER data
from a numeric variable or numeric data from a text variable. For
numeric data, if the type of data differs from the netCDF variable
type, type conversion will occur (*note Type Conversion:
(netcdf)Type Conversion.).
Errors
======
NF_GET_VARM_ TYPE returns the value NF_NOERR if no errors occurred.
Otherwise, the returned status indicates an error. Possible causes of
errors include:
* The variable ID is invalid for the specified netCDF dataset.
* The specified START, COUNT, and STRIDE generate an index which is
out of range. Note that no error checking is possible on the imap
vector.
* One or more of the values are out of the range of values
representable by the desired type.
* The specified netCDF is in define mode rather than data mode.
* The specified netCDF ID does not refer to an open netCDF dataset.
Example
=======
The following IMAP vector maps in the trivial way a 2x3x4 netCDF
variable and an internal array of the same shape:
REAL A(2,3,4) ! same shape as netCDF variable
INTEGER IMAP(3)
DATA IMAP /1, 2, 6/ ! netCDF dimension inter-element distance
! ---------------- ----------------------
! most rapidly varying 1
! intermediate 2 (=IMAP(1)*2)
! most slowly varying 6 (=IMAP(2)*3)
Using the IMAP vector above with NF_GET_VARM_REAL obtains the same
result as simply using NF_GET_VAR_REAL.
Here is an example of using NF_GET_VARM_REAL to transpose a netCDF
variable named rh which is described by the FORTRAN declaration REAL
RH(4,6) (note the size and order of the dimensions):
INCLUDE 'netcdf.inc'
...
PARAMETER (NDIM=2) ! rank of netCDF variable
INTEGER NCID ! netCDF dataset ID
INTEGER STATUS ! return code
INTEGER RHID ! variable ID
INTEGER START(NDIM) ! netCDF variable start point
INTEGER COUNT(NDIM) ! size of internal array
INTEGER STRIDE(NDIM) ! netCDF variable subsampling intervals
INTEGER IMAP(NDIM) ! internal array inter-element distances
REAL RH(6,4) ! note transposition of netCDF variable dimensions
DATA START /1, 1/ ! start at first netCDF variable element
DATA COUNT /4, 6/ ! entire netCDF variable; order corresponds
! to netCDF variable -- not internal array
DATA STRIDE /1, 1/ ! sample every netCDF element
DATA IMAP /6, 1/ ! would be /1, 4/ if not transposing
...
STATUS = NF_OPEN('foo.nc', NF_NOWRITE, NCID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
STATUS = NF_INQ_VARID(NCID, 'rh', RHID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
STATUS = NF_GET_VARM_REAL(NCID, RHID, START, COUNT, STRIDE, IMAP, RH)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
Here is another example of using NF_GET_VARM_REAL to simultaneously
transpose and subsample the same netCDF variable, by accessing every
other point of the netCDF variable:
INCLUDE 'netcdf.inc'
...
PARAMETER (NDIM=2) ! rank of netCDF variable
INTEGER NCID ! netCDF dataset ID
INTEGER STATUS ! return code
INTEGER RHID ! variable ID
INTEGER START(NDIM) ! netCDF variable start point
INTEGER COUNT(NDIM) ! size of internal array
INTEGER STRIDE(NDIM) ! netCDF variable subsampling intervals
INTEGER IMAP(NDIM) ! internal array inter-element distances
REAL RH(3,2) ! note transposition of (subsampled) dimensions
DATA START /1, 1/ ! start at first netCDF variable value
DATA COUNT /2, 3/ ! order of (subsampled) dimensions corresponds
! to netCDF variable -- not internal array
DATA STRIDE /2, 2/ ! sample every other netCDF element
DATA IMAP /3, 1/ ! would be `1, 2' if not transposing
...
STATUS = NF_OPEN('foo.nc', NF_NOWRITE, NCID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
STATUS = NF_INQ_VARID(NCID, 'rh', RHID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
STATUS = NF_GET_VARM_REAL(NCID, RHID, START, COUNT, STRIDE, IMAP, RH)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
6.29 Reading and Writing Character String Values
================================================
Character strings are not a primitive netCDF external data type, in
part because FORTRAN does not support the abstraction of
variable-length character strings (the FORTRAN LEN function returns the
static length of a character string, not its dynamic length). As a
result, a character string cannot be written or read as a single object
in the netCDF interface. Instead, a character string must be treated as
an array of characters, and array access must be used to read and write
character strings as variable data in netCDF datasets. Furthermore,
variable-length strings are not supported by the netCDF interface
except by convention; for example, you may treat a zero byte as
terminating a character string, but you must explicitly specify the
length of strings to be read from and written to netCDF variables.
Character strings as attribute values are easier to use, since the
strings are treated as a single unit for access. However, the value of
a character-string attribute is still an array of characters with an
explicit length that must be specified when the attribute is defined.
When you define a variable that will have character-string values,
use a character-position dimension as the most quickly varying dimension
for the variable (the first dimension for the variable in FORTRAN). The
length of the character-position dimension will be the maximum string
length of any value to be stored in the character-string variable.
Space for maximum-length strings will be allocated in the disk
representation of character-string variables whether you use the space
or not. If two or more variables have the same maximum length, the same
character-position dimension may be used in defining the variable
shapes.
To write a character-string value into a character-string variable,
use either entire variable access or array access. The latter requires
that you specify both a corner and a vector of edge lengths. The
character-position dimension at the corner should be one for FORTRAN.
If the length of the string to be written is n, then the vector of edge
lengths will specify n in the character-position dimension, and one for
all the other dimensions:(n, 1, 1, ..., 1).
In FORTRAN, fixed-length strings may be written to a netCDF dataset
without a terminating character, to save space. Variable-length strings
should follow the C convention of writing strings with a terminating
zero byte so that the intended length of the string can be determined
when it is later read by either C or FORTRAN programs.
The FORTRAN interface for reading and writing strings requires the
use of different functions for accessing string values and numeric
values, because standard FORTRAN does not permit the same formal
parameter to be used for both character values and numeric values. An
additional argument, specifying the declared length of the character
string passed as a value, is required for NF_PUT_VARA_TEXT and
NF_GET_VARA_TEXT. The actual length of the string is specified as the
value of the edge-length vector corresponding to the character-position
dimension.
Here is an example that defines a record variable, tx, for character
strings and stores a character-string value into the third record using
NF_PUT_VARA_TEXT. In this example, we assume the string variable and
data are to be added to an existing netCDF dataset named foo.nc that
already has an unlimited record dimension time.
INCLUDE 'netcdf.inc'
...
INTEGER TDIMS, TXLEN
PARAMETER (TDIMS=2) ! number of TX dimensions
PARAMETER (TXLEN = 15) ! length of example string
INTEGER NCID
INTEGER CHID ! char position dimension id
INTEGER TIMEID ! record dimension id
INTEGER TXID ! variable ID
INTEGER TXDIMS(TDIMS) ! variable shape
INTEGER TSTART(TDIMS), TCOUNT(TDIMS)
CHARACTER*40 TXVAL ! max length 40
DATA TXVAL /'example string'/
...
TXVAL(TXLEN:TXLEN) = CHAR(0) ! null terminate
...
STATUS = NF_OPEN('foo.nc', NF_WRITE, NCID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
STATUS = NF_REDEF(NCID) ! enter define mode
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
! define character-position dimension for strings of max length 40
STATUS = NF_DEF_DIM(NCID, "chid", 40, CHID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
! define a character-string variable
TXDIMS(1) = CHID ! character-position dimension first
TXDIMS(2) = TIMEID
STATUS = NF_DEF_VAR(NCID, "tx", NF_CHAR, TDIMS, TXDIMS, TXID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
STATUS = NF_ENDDEF(NCID) ! leave define mode
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
! write txval into tx netCDF variable in record 3
TSTART(1) = 1 ! start at beginning of variable
TSTART(2) = 3 ! record number to write
TCOUNT(1) = TXLEN ! number of chars to write
TCOUNT(2) = 1 ! only write one record
STATUS = NF_PUT_VARA_TEXT (NCID, TXID, TSTART, TCOUNT, TXVAL)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
6.30 Fill Values
================
What happens when you try to read a value that was never written in an
open netCDF dataset? You might expect that this should always be an
error, and that you should get an error message or an error status
returned. You do get an error if you try to read data from a netCDF
dataset that is not open for reading, if the variable ID is invalid for
the specified netCDF dataset, or if the specified indices are not
properly within the range defined by the dimension lengths of the
specified variable. Otherwise, reading a value that was not written
returns a special fill value used to fill in any undefined values when
a netCDF variable is first written.
You may ignore fill values and use the entire range of a netCDF
external data type, but in this case you should make sure you write all
data values before reading them. If you know you will be writing all
the data before reading it, you can specify that no prefilling of
variables with fill values will occur by calling NF_SET_FILL before
writing. This may provide a significant performance gain for netCDF
writes.
The variable attribute _FillValue may be used to specify the fill
value for a variable. Their are default fill values for each type,
defined in the include file netcdf.inc: NF_FILL_CHAR, NF_FILL_INT1
(same as NF_FILL_BYTE), NF_FILL_INT2 (same as NF_FILL_SHORT),
NF_FILL_INT, NF_FILL_REAL (same as NF_FILL_FLOAT), and NF_FILL_DOUBLE.
The netCDF byte and character types have different default fill
values. The default fill value for characters is the zero byte, a
useful value for detecting the end of variable-length C character
strings. If you need a fill value for a byte variable, it is
recommended that you explicitly define an appropriate _FillValue
attribute, as generic utilities such as ncdump will not assume a
default fill value for byte variables.
Type conversion for fill values is identical to type conversion for
other values: attempting to convert a value from one type to another
type that can't represent the value results in a range error. Such
errors may occur on writing or reading values from a larger type (such
as double) to a smaller type (such as float), if the fill value for the
larger type cannot be represented in the smaller type.
6.31 NF_RENAME_VAR
==================
The function NF_RENAME_VAR changes the name of a netCDF variable in an
open netCDF dataset. If the new name is longer than the old name, the
netCDF dataset must be in define mode. You cannot rename a variable to
have the name of any existing variable.
Usage
=====
INTEGER FUNCTION NF_RENAME_VAR (INTEGER NCID, INTEGER VARID,
CHARACTER*(*) NEWNAM)
`NCID'
NetCDF ID, from a previous call to NF_OPEN or NF_CREATE.
`VARID'
Variable ID.
`NAME'
New name for the specified variable.
Errors
======
NF_RENAME_VAR returns the value NF_NOERR if no errors occurred.
Otherwise, the returned status indicates an error. Possible causes of
errors include:
* The new name is in use as the name of another variable.
* The variable ID is invalid for the specified netCDF dataset.
* The specified netCDF ID does not refer to an open netCDF dataset.
Example
=======
Here is an example using NF_RENAME_VAR to rename the variable rh to
rel_hum in an existing netCDF dataset named foo.nc:
INCLUDE 'netcdf.inc'
...
INTEGER STATUS, NCID
INTEGER RHID ! variable ID
...
STATUS = NF_OPEN ('foo.nc', NF_WRITE, NCID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
STATUS = NF_REDEF (NCID) ! enter definition mode
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
STATUS = NF_INQ_VARID (NCID, 'rh', RHID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
STATUS = NF_RENAME_VAR (NCID, RHID, 'rel_hum')
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
STATUS = NF_ENDDEF (NCID) ! leave definition mode
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
6.32 Change between Collective and Independent Parallel Access: NF_VAR_PAR_ACCESS
=================================================================================
The function NF_VAR_PAR_ACCESS changes whether read/write operations on
a parallel file system are performed collectively (the default) or
independently on the variable. This function can only be called if the
file was created with NF_CREATE_PAR (see *note NF_CREATE_PAR::) or
opened with NF_OPEN_PAR (see *note NF_OPEN_PAR::).
This function is only available if the netCDF library was built with
a HDF5 library for which -enable-parallel was used, and which was
linked (like HDF5) to MPI libraries.
Calling this function affects only the open file - information about
whether a variable is to be accessed collectively or independently is
not written to the data file. Every time you open a file on a parallel
file system, all variables default to collective operations. The change
a variable to independent lasts only as long as that file is open.
The variable can be changed from collective to independent, and back,
as often as desired.
Usage
=====
INTEGER NF_VAR_PAR_ACCESS(INTEGER NCID, INTEGER VARID, INTEGER ACCESS);
`NCID'
NetCDF ID, from a previous call to NF_OPEN_PAR (see *note
NF_OPEN_PAR::) or NF_CREATE_PAR (see *note NF_CREATE_PAR::).
`varid'
Variable ID.
`access'
NF_INDEPENDENT to set this variable to independent operations.
NF_COLLECTIVE to set it to collective operations.
Return Values
=============
`NF_NOERR'
No error.
`NF_ENOTVAR'
No variable found.
`NF_ENOTNC4'
Not a netCDF-4 file.
`NF_NOPAR'
File not opened for parallel access.
Example
=======
This example comes from test program nf_test/ftst_parallel.F. For this
test to be run, netCDF must have been built with a parallel-enabled
HDF5, and -enable-parallel-tests must have been used when configuring
netcdf.
retval = nf_var_par_access(ncid, varid, nf_collective)
if (retval .ne. nf_noerr) stop 2
7 Attributes
************
7.1 Attributes Introduction
===========================
Attributes may be associated with each netCDF variable to specify such
properties as units, special values, maximum and minimum valid values,
scaling factors, and offsets. Attributes for a netCDF dataset are
defined when the dataset is first created, while the netCDF dataset is
in define mode. Additional attributes may be added later by reentering
define mode. A netCDF attribute has a netCDF variable to which it is
assigned, a name, a type, a length, and a sequence of one or more
values. An attribute is designated by its variable ID and name. When an
attribute name is not known, it may be designated by its variable ID
and number in order to determine its name, using the function
NF_INQ_ATTNAME.
The attributes associated with a variable are typically defined
immediately after the variable is created, while still in define mode.
The data type, length, and value of an attribute may be changed even
when in data mode, as long as the changed attribute requires no more
space than the attribute as originally defined.
It is also possible to have attributes that are not associated with
any variable. These are called global attributes and are identified by
using NF_GLOBAL as a variable pseudo-ID. Global attributes are usually
related to the netCDF dataset as a whole and may be used for purposes
such as providing a title or processing history for a netCDF dataset.
Attributes are much more useful when they follow established
community conventions. *Note Attribute Conventions: (netcdf)Attribute
Conventions.
Operations supported on attributes are:
* Create an attribute, given its variable ID, name, data type,
length, and value.
* Get attribute's data type and length from its variable ID and name.
* Get attribute's value from its variable ID and name.
* Copy attribute from one netCDF variable to another.
* Get name of attribute from its number.
* Rename an attribute.
* Delete an attribute.
7.2 NF_PUT_ATT_ TYPE
====================
The function NF_PUT_ATT_ TYPE adds or changes a variable attribute or
global attribute of an open netCDF dataset. If this attribute is new,
or if the space required to store the attribute is greater than before,
the netCDF dataset must be in define mode.
Usage
=====
Although it's possible to create attributes of all types, text and
double attributes are adequate for most purposes.
INTEGER FUNCTION NF_PUT_ATT_TEXT (INTEGER NCID, INTEGER VARID,
CHARACTER*(*) NAME, INTEGER LEN,
CHARACTER*(*) TEXT)
INTEGER FUNCTION NF_PUT_ATT_INT1 (INTEGER NCID, INTEGER VARID,
CHARACTER*(*) NAME, INTEGER XTYPE,
LEN, INTEGER*1 I1VALS(*))
INTEGER FUNCTION NF_PUT_ATT_INT2 (INTEGER NCID, INTEGER VARID,
CHARACTER*(*) NAME, INTEGER XTYPE,
LEN, INTEGER*2 I2VALS(*))
INTEGER FUNCTION NF_PUT_ATT_INT (INTEGER NCID, INTEGER VARID,
CHARACTER*(*) NAME, INTEGER XTYPE,
LEN, INTEGER IVALS(*))
INTEGER FUNCTION NF_PUT_ATT_REAL (INTEGER NCID, INTEGER VARID,
CHARACTER*(*) NAME, INTEGER XTYPE,
LEN, REAL RVALS(*))
INTEGER FUNCTION NF_PUT_ATT_DOUBLE(INTEGER NCID, INTEGER VARID,
CHARACTER*(*) NAME, INTEGER XTYPE,
LEN, DOUBLE DVALS(*))
INTEGER FUNCTION NF_PUT_ATT (INTEGER NCID, INTEGER VARID,
CHARACTER*(*) NAME, INTEGER XTYPE,
LEN, * VALS(*))
`NCID'
NetCDF ID, from a previous call to NF_OPEN or NF_CREATE.
`VARID'
Variable ID of the variable to which the attribute will be
assigned or NF_GLOBAL for a global attribute.
`NAME'
Attribute name. Attribute name conventions are assumed by some
netCDF generic applications, e.g., `units' as the name for a string
attribute that gives the units for a netCDF variable. *Note
Attribute Conventions: (netcdf)Attribute Conventions.
`XTYPE'
One of the set of predefined netCDF external data types. The type
of this parameter, NF_TYPE, is defined in the netCDF header file.
The valid netCDF external data types are NF_BYTE, NF_CHAR,
NF_SHORT, NF_INT, NF_FLOAT, and NF_DOUBLE. Although it's possible
to create attributes of all types, NF_CHAR and NF_DOUBLE
attributes are adequate for most purposes.
`LEN'
Number of values provided for the attribute.
`TEXT'
`I1VALS'
`I2VALS'
`IVALS'
`RVALS'
`DVALS'
`VALS'
An array of LEN attribute values. The data should be of a type
appropriate for the function called. You cannot write CHARACTER
data into a numeric attribute or numeric data into a text
attribute. For numeric data, if the type of data differs from the
attribute type, type conversion will occur *Note Type Conversion:
(netcdf)Type Conversion.
Errors
======
NF_PUT_ATT_ TYPE returns the value NF_NOERR if no errors occurred.
Otherwise, the returned status indicates an error. Possible causes of
errors include:
* The variable ID is invalid for the specified netCDF dataset.
* The specified netCDF type is invalid.
* The specified length is negative.
* The specified open netCDF dataset is in data mode and the specified
attribute would expand.
* The specified open netCDF dataset is in data mode and the specified
attribute does not already exist.
* The specified netCDF ID does not refer to an open netCDF dataset.
* The number of attributes for this variable exceeds NF_MAX_ATTRS.
Example
=======
Here is an example using NF_PUT_ATT_DOUBLE to add a variable attribute
named valid_range for a netCDF variable named rh and a global attribute
named title to an existing netCDF dataset named foo.nc:
INCLUDE 'netcdf.inc'
...
INTEGER STATUS, NCID
INTEGER RHID ! variable ID
DOUBLE RHRNGE(2)
DATA RHRNGE /0.0D0, 100.0D0/
...
STATUS = NF_OPEN ('foo.nc', NF_WRITE, NCID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
STATUS = NF_REDEF (NCID) ! enter define mode
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
STATUS = NF_INQ_VARID (NCID, 'rh', RHID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
STATUS = NF_PUT_ATT_DOUBLE (NCID, RHID, 'valid_range', NF_DOUBLE, &
2, RHRNGE)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
STATUS = NF_PUT_ATT_TEXT (NCID, NF_GLOBAL, 'title', 19,
'example netCDF dataset')
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
STATUS = NF_ENDDEF (NCID) ! leave define mode
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
7.3 NF_INQ_ATT Family
=====================
This family of functions returns information about a netCDF attribute.
All but one of these functions require the variable ID and attribute
name; the exception is NF_INQ_ATTNAME. Information about an attribute
includes its type, length, name, and number. See the NF_GET_ATT family
for getting attribute values.
The function NF_INQ_ATTNAME gets the name of an attribute, given its
variable ID and number. This function is useful in generic applications
that need to get the names of all the attributes associated with a
variable, since attributes are accessed by name rather than number in
all other attribute functions. The number of an attribute is more
volatile than the name, since it can change when other attributes of
the same variable are deleted. This is why an attribute number is not
called an attribute ID.
The function NF_INQ_ATT returns the attribute's type and length. The
other functions each return just one item of information about an
attribute.
Usage
=====
INTEGER FUNCTION NF_INQ_ATT (INTEGER NCID, INTEGER VARID,
CHARACTER*(*) NAME, INTEGER xtype,
INTEGER len)
INTEGER FUNCTION NF_INQ_ATTTYPE(INTEGER NCID, INTEGER VARID,
CHARACTER*(*) NAME, INTEGER xtype)
INTEGER FUNCTION NF_INQ_ATTLEN (INTEGER NCID, INTEGER VARID,
CHARACTER*(*) NAME, INTEGER len)
INTEGER FUNCTION NF_INQ_ATTNAME(INTEGER NCID, INTEGER VARID,
INTEGER ATTNUM, CHARACTER*(*) name)
INTEGER FUNCTION NF_INQ_ATTID (INTEGER NCID, INTEGER VARID,
CHARACTER*(*) NAME, INTEGER attnum)
`NCID'
NetCDF ID, from a previous call to NF_OPEN or NF_CREATE.
`VARID'
Variable ID of the attribute's variable, or NF_GLOBAL for a global
attribute.
`NAME'
Attribute name. For NF_INQ_ATTNAME, this is a pointer to the
location for the returned attribute name.
`xtype'
Returned attribute type, one of the set of predefined netCDF
external data types. The valid netCDF external data types are
NF_BYTE, NF_CHAR, NF_SHORT, NF_INT, NF_FLOAT, and NF_DOUBLE.
`len'
Returned number of values currently stored in the attribute. For a
string-valued attribute, this is the number of characters in the
string.
`attnum'
For NF_INQ_ATTNAME, the input attribute number; for NF_INQ_ATTID,
the returned attribute number. The attributes for each variable are
numbered from 1 (the first attribute) to NATTS, where NATTS is the
number of attributes for the variable, as returned from a call to
NF_INQ_VARNATTS.
(If you already know an attribute name, knowing its number is not
very useful, because accessing information about an attribute
requires its name.)
Errors
======
Each function returns the value NF_NOERR if no errors occurred.
Otherwise, the returned status indicates an error. Possible causes of
errors include:
* The variable ID is invalid for the specified netCDF dataset.
* The specified attribute does not exist.
* The specified netCDF ID does not refer to an open netCDF dataset.
* For NF_INQ_ATTNAME, the specified attribute number is negative or
more than the number of attributes defined for the specified
variable.
Example
=======
Here is an example using NF_INQ_ATT to find out the type and length of
a variable attribute named valid_range for a netCDF variable named rh
and a global attribute named title in an existing netCDF dataset named
foo.nc:
INCLUDE 'netcdf.inc'
...
INTEGER STATUS, NCID
INTEGER RHID ! variable ID
INTEGER VRLEN, TLEN ! attribute lengths
...
STATUS = NF_OPEN ('foo.nc', NF_NOWRITE, NCID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
STATUS = NF_INQ_VARID (NCID, 'rh', RHID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
STATUS = NF_INQ_ATTLEN (NCID, RHID, 'valid_range', VRLEN)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
STATUS = NF_INQ_ATTLEN (NCID, NF_GLOBAL, 'title', TLEN)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
7.4 NF_GET_ATT_ TYPE
====================
Members of the NF_GET_ATT_ TYPE family of functions get the value(s) of
a netCDF attribute, given its variable ID and name.
Usage
=====
INTEGER FUNCTION NF_GET_ATT_TEXT (INTEGER NCID, INTEGER VARID,
CHARACTER*(*) NAME,
CHARACTER*(*) text)
INTEGER FUNCTION NF_GET_ATT_INT1 (INTEGER NCID, INTEGER VARID,
CHARACTER*(*) NAME,
INTEGER*1 i1vals(*))
INTEGER FUNCTION NF_GET_ATT_INT2 (INTEGER NCID, INTEGER VARID,
CHARACTER*(*) NAME,
INTEGER*2 i2vals(*))
INTEGER FUNCTION NF_GET_ATT_INT (INTEGER NCID, INTEGER VARID,
CHARACTER*(*) NAME,
INTEGER ivals(*))
INTEGER FUNCTION NF_GET_ATT_REAL (INTEGER NCID, INTEGER VARID,
CHARACTER*(*) NAME,
REAL rvals(*))
INTEGER FUNCTION NF_GET_ATT_DOUBLE (INTEGER NCID, INTEGER VARID,
CHARACTER*(*) NAME,
DOUBLE dvals(*))
INTEGER FUNCTION NF_GET_ATT (INTEGER NCID, INTEGER VARID,
CHARACTER*(*) NAME, * vals(*))
`NCID'
NetCDF ID, from a previous call to NF_OPEN or NF_CREATE.
`VARID'
Variable ID of the attribute's variable, or NF_GLOBAL for a global
attribute.
`NAME'
Attribute name.
`TEXT'
`I1VALS'
`I2VALS'
`IVALS'
`RVALS'
`DVALS'
`VALS'
Returned attribute values. All elements of the vector of attribute
values are returned, so you must provide enough space to hold
them. If you don't know how much space to reserve, call
NF_INQ_ATTLEN first to find out the length of the attribute. You
cannot read character data from a numeric variable or numeric data
from a text variable. For numeric data, if the type of data
differs from the netCDF variable type, type conversion will occur.
*Note Type Conversion: (netcdf)Type Conversion.
Errors
======
NF_GET_ATT_ TYPE returns the value NF_NOERR if no errors occurred.
Otherwise, the returned status indicates an error. Possible causes of
errors include:
* The variable ID is invalid for the specified netCDF dataset.
* The specified attribute does not exist.
* The specified netCDF ID does not refer to an open netCDF dataset.
* One or more of the attribute values are out of the range of values
representable by the desired type.
Example
=======
Here is an example using NF_GET_ATT_DOUBLE to determine the values of a
variable attribute named valid_range for a netCDF variable named rh and
a global attribute named title in an existing netCDF dataset named
foo.nc. In this example, it is assumed that we don't know how many
values will be returned, but that we do know the types of the
attributes. Hence, to allocate enough space to store them, we must
first inquire about the length of the attributes.
INCLUDE 'netcdf.inc'
...
PARAMETER (MVRLEN=3) ! max number of "valid_range" values
PARAMETER (MTLEN=80) ! max length of "title" attribute
INTEGER STATUS, NCID
INTEGER RHID ! variable ID
INTEGER VRLEN, TLEN ! attribute lengths
DOUBLE PRECISION VRVAL(MVRLEN) ! vr attribute values
CHARACTER*80 TITLE ! title attribute values
...
STATUS = NF_OPEN ('foo.nc', NF_WRITE, NCID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
STATUS = NF_INQ_VARID (NCID, 'rh', RHID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
! find out attribute lengths, to make sure we have enough space
STATUS = NF_INQ_ATTLEN (NCID, RHID, 'valid_range', VRLEN)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
STATUS = NF_INQ_ATTLEN (NCID, NF_GLOBAL, 'title', TLEN)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
! get attribute values, if not too big
IF (VRLEN .GT. MVRLEN) THEN
WRITE (*,*) 'valid_range attribute too big!'
CALL EXIT
ELSE
STATUS = NF_GET_ATT_DOUBLE (NCID, RHID, 'valid_range', VRVAL)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
ENDIF
IF (TLEN .GT. MTLEN) THEN
WRITE (*,*) 'title attribute too big!'
CALL EXIT
ELSE
STATUS = NF_GET_ATT_TEXT (NCID, NF_GLOBAL, 'title', TITLE)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
ENDIF
7.5 NF_COPY_ATT
===============
The function NF_COPY_ATT copies an attribute from one open netCDF
dataset to another. It can also be used to copy an attribute from one
variable to another within the same netCDF.
If used to copy an attribute of user-defined type, then that
user-defined type must already be defined in the target file. In the
case of user-defined attributes, enddef/redef is called for ncid_in and
ncid_out if they are in define mode. (This is the ensure that all
user-defined types are committed to the file(s) before the copy is
attempted.)
Usage
=====
INTEGER FUNCTION NF_COPY_ATT (INTEGER NCID_IN, INTEGER VARID_IN,
CHARACTER*(*) NAME, INTEGER NCID_OUT,
INTEGER VARID_OUT)
`NCID_IN'
The netCDF ID of an input netCDF dataset from which the attribute
will be copied, from a previous call to NF_OPEN or NF_CREATE.
`VARID_IN'
ID of the variable in the input netCDF dataset from which the
attribute will be copied, or NF_GLOBAL for a global attribute.
`NAME'
Name of the attribute in the input netCDF dataset to be copied.
`NCID_OUT'
The netCDF ID of the output netCDF dataset to which the attribute
will be copied, from a previous call to NF_OPEN or NF_CREATE. It is
permissible for the input and output netCDF IDs to be the same. The
output netCDF dataset should be in define mode if the attribute to
be copied does not already exist for the target variable, or if it
would cause an existing target attribute to grow.
`VARID_OUT'
ID of the variable in the output netCDF dataset to which the
attribute will be copied, or NF_GLOBAL to copy to a global
attribute.
Errors
======
NF_COPY_ATT returns the value NF_NOERR if no errors occurred.
Otherwise, the returned status indicates an error. Possible causes of
errors include:
* The input or output variable ID is invalid for the specified netCDF
dataset.
* The specified attribute does not exist.
* The output netCDF is not in define mode and the attribute is new
for the output dataset is larger than the existing attribute.
* The input or output netCDF ID does not refer to an open netCDF
dataset.
Example
=======
Here is an example using NF_COPY_ATT to copy the variable attribute
units from the variable rh in an existing netCDF dataset named foo.nc
to the variable avgrh in another existing netCDF dataset named bar.nc,
assuming that the variable avgrh already exists, but does not yet have
a units attribute:
INCLUDE 'netcdf.inc'
...
INTEGER STATUS ! error status
INTEGER NCID1, NCID2 ! netCDF IDs
INTEGER RHID, AVRHID ! variable IDs
...
STATUS = NF_OPEN ('foo.nc', NF_NOWRITE, NCID1)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
STATUS = NF_OPEN ('bar.nc', NF_WRITE, NCID2)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
STATUS = NF_INQ_VARID (NCID1, 'rh', RHID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
STATUS = NF_INQ_VARID (NCID2, 'avgrh', AVRHID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
STATUS = NF_REDEF (NCID2) ! enter define mode
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
! copy variable attribute from "rh" to "avgrh"
STATUS = NF_COPY_ATT (NCID1, RHID, 'units', NCID2, AVRHID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
STATUS = NF_ENDDEF (NCID2) ! leave define mode
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
7.6 NF_RENAME_ATT
=================
The function NF_RENAME_ATT changes the name of an attribute. If the new
name is longer than the original name, the netCDF dataset must be in
define mode. You cannot rename an attribute to have the same name as
another attribute of the same variable.
Usage
=====
INTEGER FUNCTION NF_RENAME_ATT (INTEGER NCID, INTEGER VARID,
CHARACTER*(*) NAME,
CHARACTER*(*) NEWNAME)
`NCID'
NetCDF ID, from a previous call to NF_OPEN or NF_CREATE
`VARID'
ID of the attribute's variable, or NF_GLOBAL for a global attribute
`NAME'
The current attribute name.
`NEWNAME'
The new name to be assigned to the specified attribute. If the new
name is longer than the current name, the netCDF dataset must be in
define mode.
Errors
======
NF_RENAME_ATT returns the value NF_NOERR if no errors occurred.
Otherwise, the returned status indicates an error. Possible causes of
errors include:
* The specified variable ID is not valid.
* The new attribute name is already in use for another attribute of
the specified variable.
* The specified netCDF dataset is in data mode and the new name is
longer than the old name.
* The specified attribute does not exist.
* The specified netCDF ID does not refer to an open netCDF dataset.
Example
=======
Here is an example using NF_RENAME_ATT to rename the variable attribute
units to Units for a variable rh in an existing netCDF dataset named
foo.nc:
INCLUDE "netcdf.inc"
...
INTEGER STATUS ! error status
INTEGER NCID ! netCDF ID
INTEGER RHID ! variable ID
...
STATUS = NF_OPEN ("foo.nc", NF_NOWRITE, NCID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
STATUS = NF_INQ_VARID (NCID, "rh", RHID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
! rename attribute
STATUS = NF_RENAME_ATT (NCID, RHID, "units", "Units")
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
7.7 NF_DEL_ATT
==============
The function NF_DEL_ATT deletes a netCDF attribute from an open netCDF
dataset. The netCDF dataset must be in define mode.
Usage
=====
INTEGER FUNCTION NF_DEL_ATT (INTEGER NCID, INTEGER VARID,
CHARACTER*(*) NAME)
`NCID'
NetCDF ID, from a previous call to NF_OPEN or NF_CREATE.
`VARID'
ID of the attribute's variable, or NF_GLOBAL for a global
attribute.
`NAME'
The name of the attribute to be deleted.
Errors
======
NF_DEL_ATT returns the value NF_NOERR if no errors occurred. Otherwise,
the returned status indicates an error. Possible causes of errors
include:
* The specified variable ID is not valid.
* The specified netCDF dataset is in data mode.
* The specified attribute does not exist.
* The specified netCDF ID does not refer to an open netCDF dataset.
Example
=======
Here is an example using NF_DEL_ATT to delete the variable attribute
Units for a variable rh in an existing netCDF dataset named foo.nc:
INCLUDE 'netcdf.inc'
...
INTEGER STATUS ! error status
INTEGER NCID ! netCDF ID
INTEGER RHID ! variable ID
...
STATUS = NF_OPEN ('foo.nc', NF_WRITE, NCID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
STATUS = NF_INQ_VARID (NCID, 'rh', RHID)
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
...
! delete attribute
STATUS = NF_REDEF (NCID) ! enter define mode
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
STATUS = NF_DEL_ATT (NCID, RHID, 'Units')
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
STATUS = NF_ENDDEF (NCID) ! leave define mode
IF (STATUS .NE. NF_NOERR) CALL HANDLE_ERR(STATUS)
Appendix A NetCDF 2 to NetCDF 3 Fortran 77 Transition Guide
***********************************************************
A.1 Overview of FORTRAN interface changes
=========================================
NetCDF version 3 includes a complete rewrite of the netCDF library. It
is about twice as fast as the previous version. The netCDF file format
is unchanged, so files written with version 3 can be read with version
2 code and vice versa.
The core library is now written in ANSI C. You must have an ANSI C
compiler to compile this version. The FORTRAN interface is layered on
top of the C interface using a different technique than was used in
netCDF-2.
Rewriting the library offered an opportunity to implement improved C
and FORTRAN interfaces that provide some significant benefits:
* type safety, by eliminating the need to use type punning in
arguments;
* automatic type conversions, by eliminating the undesirable coupling
between the language-independent external netCDF types (NF_BYTE,
..., NF_DOUBLE) and language-dependent internal data types (INT*1,
..., DOUBLE PRECISION);
* support for future enhancements, by eliminating obstacles to the
clean addition of support for packed data and multithreading;
* more standard error behavior, by uniformly communicating an error
status back to the calling program in the return value of each
function.
It is not necessary to rewrite programs that use the version 2
FORTRAN interface, because the netCDF-3 library includes a backward
compatibility interface that supports all the old functions, globals,
and behavior. We are hoping that the benefits of the new interface will
be an incentive to use it in new netCDF applications. It is possible to
convert old applications to the new interface incrementally, replacing
netCDF-2 calls with the corresponding netCDF-3 calls one at a time.
Other changes in the implementation of netCDF result in improved
portability, maintainability, and performance on most platforms. A
clean separation between I/O and type layers facilitates
platform-specific optimizations. The new library no longer uses a
vendor-provided XDR library, which simplifies linking programs that use
netCDF and speeds up data access significantly in most cases.
A.2 The New FORTRAN Interface
=============================
First, here's an example of FORTRAN code that uses the netCDF-2
interface:
! Use a buffer big enough for values of any type
DOUBLE PRECISION DBUF(NDATA)
REAL RBUF(NDATA)
...
EQUIVALENCE (RBUF, DBUF), ...
INT XTYPE ! to hold the actual type of the data
INT STATUS ! for error status
! Get the actual data type
CALL NCVINQ(NCID, VARID, ...,XTYPE, ...)
...
! Get the data
CALL NCVGT(NCID, VARID, START, COUNT, DBUF, STATUS)
IF(STATUS .NE. NCNOERR) THEN
PRINT *, 'Cannot get data, error code =', STATUS
! Deal with error
...
ENDIF
IF (XTYPE .EQ. NCDOUBLE) THEN
CALL DANALYZE(DBUF)
ELSEIF (XTYPE .EQ. NCFLOAT) THEN
CALL RANALYZE(RBUF)
...
ENDIF
Here's how you might handle this with the new netCDF-3 FORTRAN
interface:
! I want to use doubles for my analysis
DOUBLE PRECISION DBUF(NDATA)
INT STATUS
! So I use a function that gets the data as doubles.
STATUS = NF_GET_VARA_DOUBLE(NCID, VARID, START, COUNT, DBUF)
IF(STATUS .NE. NF_NOERR) THEN
PRINT *, 'Cannot get data, ', NF_STRERROR(STATUS)
! Deal with error
...
ENDIF
CALL DANALYZE(DBUF)
The example above illustrates changes in function names, data type
conversion, and error handling, discussed in detail in the sections
below.
A.3 Function Naming Conventions
===============================
The netCDF-3 C library employs a new naming convention, intended to
make netCDF programs more readable. For example, the name of the
function to rename a variable is now NF_RENAME_VAR instead of the
previous NCVREN.
All netCDF-3 FORTRAN function names begin with the NF_ prefix. The
second part of the name is a verb, like GET, PUT, INQ (for inquire), or
OPEN. The third part of the name is typically the object of the verb:
for example DIM, VAR, or ATT for functions dealing with dimensions,
variables, or attributes. To distinguish the various I/O operations for
variables, a single character modifier is appended to VAR:
* VAR entire variable access
* VAR1 single value access
* VARA array or array section access
* VARS strided access to a subsample of values
* VARM mapped access to values not contiguous in memory
At the end of the name for variable and attribute functions, there is
a component indicating the type of the final argument: TEXT, INT1,
INT2, INT, REAL, or DOUBLE. This part of the function name indicates
the type of the data container you are using in your program: character
string, 1-byte integer, and so on.
Also, all PARAMETER names in the public FORTRAN interface begin with
the prefix NF_. For example, the PARAMETER which was formerly MAXNCNAM
is now NF_MAX_NAME, and the former FILFLOAT is now NF_FILL_FLOAT.
As previously mentioned, all the old names are still supported for
backward compatibility.
A.4 Type Conversion
===================
With the new interface, users need not be aware of the external type of
numeric variables, since automatic conversion to or from any desired
numeric type is now available. You can use this feature to simplify
code, by making it independent of external types. The elimination of
type punning prevents some kinds of type errors that could occur with
the previous interface. Programs may be made more robust with the new
interface, because they need not be changed to accommodate a change to
the external type of a variable.
If conversion to or from an external numeric type is necessary, it is
handled by the library. This automatic conversion and separation of
external data representation from internal data types will become even
more important in netCDF version 4, when new external types will be
added for packed data for which there is no natural corresponding
internal type, for example, arrays of 11-bit values.
Converting from one numeric type to another may result in an error if
the target type is not capable of representing the converted value. (In
netCDF-2, such overflows can only happen in the XDR layer.) For
example, a REAL may not be able to hold data stored externally as an
NF_DOUBLE (an IEEE floating-point number). When accessing an array of
values, an NF_ERANGE error is returned if one or more values are out of
the range of representable values, but other values are converted
properly.
Note that mere loss of precision in type conversion does not return
an error. Thus, if you read double precision values into an INTEGER,
for example, no error results unless the magnitude of the double
precision value exceeds the representable range of INTEGERs on your
platform. Similarly, if you read a large integer into a REAL incapable
of representing all the bits of the integer in its mantissa, this loss
There are two new functions in netCDF-3 that don't correspond to any
netCDF-2 functions: NF_INQ_LIBVERS and NF_STRERROR. The version ation
The previous implementation returned an error when the same dimension
was used more than once in specifying the shape of a variable in
ncvardef. This restriction is relaxed in the netCDF-3 implementation,
because an autocorrelation matrix is a good example where using the
same dimension twice makes sense.
In the new interface, units for the IMAP argument to the NF_PUT_VARM
and NF_GET_VARM families of functions are now in terms of the number of
data elements of the desired internal type, not in terms of bytes as in
the netCDF version-2 mapped access interfaces.
Following is a table of netCDF-2 function names and names of the
corresponding netCDF-3 functions. For parameter lists of netCDF-2
functions, see the netCDF-2 User's Guide.
`NCABOR'
NF_ABORT
`NCACPY'
NF_COPY_ATT
`NCADEL'
NF_DEL_ATT
`NCAGT'
NF_GET_ATT_DOUBLE, NF_GET_ATT_REAL, NF_GET_ATT_INT,
NF_GET_ATT_INT1, NF_GET_ATT_INT2
`NCAGTC'
NF_GET_ATT_TEXT
`NCAINQ'
NF_INQ_ATT, NF_INQ_ATTID, NF_INQ_ATTLEN, NF_INQ_ATTTYPE
`NCANAM'
NF_INQ_ATTNAME
`NCAPT'
NF_PUT_ATT_DOUBLE, NF_PUT_ATT_REAL, NF_PUT_ATT_INT,
NF_PUT_ATT_INT1NF_PUT
Appendix B Summary of FORTRAN 77 Interface
******************************************
Input parameters are in upper case, output parameters are in lower
case. The FORTRAN types of all the parameters are listed alphabetically
by parameter name below the function declarations.
CHARACTER*80 FUNCTION NF_INQ_LIBVERS()
CHARACTER*80 FUNCTION NF_STRERROR (NCERR)
INTEGER FUNCTION NF_CREATE (PATH, CMODE, ncid)
INTEGER FUNCTION NF_OPEN (PATH, MODE, ncid)
INTEGER FUNCTION NF_SET_FILL (NCID, FILLMODE, old_mode)
INTEGER FUNCTION NF_REDEF (NCID)
INTEGER FUNCTION NF_ENDDEF (NCID)
INTEGER FUNCTION NF_SYNC (NCID)
INTEGER FUNCTION NF_ABORT (NCID)
INTEGER FUNCTION NF_CLOSE (NCID)
INTEGER FUNCTION NF_INQ (NCID, ndims, nvars, ngatts,
unlimdimid)
INTEGER FUNCTION NF_INQ_NDIMS (NCID, ndims)
INTEGER FUNCTION NF_INQ_NVARS (NCID, nvars)
INTEGER FUNCTION NF_INQ_NATTS (NCID, ngatts)
INTEGER FUNCTION NF_INQ_UNLIMDIM (NCID, unlimdimid)
INTEGER FUNCTION NF_DEF_DIM (NCID, NAME, LEN, dimid)
INTEGER FUNCTION NF_INQ_DIMID (NCID, NAME, dimid)
INTEGER FUNCTION NF_INQ_DIM (NCID, DIMID, name, len)
INTEGER FUNCTION NF_INQ_DIMNAME (NCID, DIMID, name)
INTEGER FUNCTION NF_INQ_DIMLEN (NCID, DIMID, len)
INTEGER FUNCTION NF_RENAME_DIM (NCID, DIMID, NAME)
INTEGER FUNCTION NF_DEF_VAR (NCID, NAME, XTYPE, NDIMS, DIMIDS,
varid)
INTEGER FUNCTION NF_INQ_VAR (NCID, VARID, name, xtype, ndims,
dimids, natts)
INTEGER FUNCTION NF_INQ_VARID (NCID, NAME, varid)
INTEGER FUNCTION NF_INQ_VARNAME (NCID, VARID, name)
INTEGER FUNCTION NF_INQ_VARTYPE (NCID, VARID, xtype)
INTEGER FUNCTION NF_INQ_VARNDIMS (NCID, VARID, ndims)
INTEGER FUNCTION NF_INQ_VARDIMID (NCID, VARID, DIMIDS)
INTEGER FUNCTION NF_INQ_VARNATTS (NCID, VARID, natts)
INTEGER FUNCTION NF_RENAME_VAR (NCID, VARID, NAME)
INTEGER FUNCTION NF_PUT_VAR_TEXT (NCID, VARID, TEXT)
INTEGER FUNCTION NF_GET_VAR_TEXT (NCID, VARID, text)
INTEGER FUNCTION NF_PUT_VAR_INT1 (NCID, VARID, I1VAL)
INTEGER FUNCTION NF_GET_VAR_INT1 (NCID, VARID, i1val)
INTEGER FUNCTION NF_PUT_VAR_INT2 (NCID, VARID, I2VAL)
INTEGER FUNCTION NF_GET_VAR_INT2 (NCID, VARID, i2val)
INTEGER FUNCTION NF_PUT_VAR_INT (NCID, VARID, IVAL)
INTEGER FUNCTION NF_GET_VAR_INT (NCID, VARID, ival)
INTEGER FUNCTION NF_PUT_VAR_REAL (NCID, VARID, RVAL)
INTEGER FUNCTION NF_GET_VAR_REAL (NCID, VARID, rval)
INTEGER FUNCTION NF_PUT_VAR_DOUBLE (NCID, VARID, DVAL)
INTEGER FUNCTION NF_GET_VAR_DOUBLE (NCID, VARID, dval)
INTEGER FUNCTION NF_PUT_VAR1_TEXT (NCID, VARID, INDEX, TEXT)
INTEGER FUNCTION NF_GET_VAR1_TEXT (NCID, VARID, INDEX, text)
INTEGER FUNCTION NF_PUT_VAR1_INT1 (NCID, VARID, INDEX, I1VAL)
INTEGER FUNCTION NF_GET_VAR1_INT1 (NCID, VARID, INDEX, i1val)
INTEGER FUNCTION NF_PUT_VAR1_INT2 (NCID, VARID, INDEX, I2VAL)
INTEGER FUNCTION NF_GET_VAR1_INT2 (NCID, VARID, INDEX, i2val)
INTEGER FUNCTION NF_PUT_VAR1_INT (NCID, VARID, INDEX, IVAL)
INTEGER FUNCTION NF_GET_VAR1_INT (NCID, VARID, INDEX, ival)
INTEGER FUNCTION NF_PUT_VAR1_REAL (NCID, VARID, INDEX, RVAL)
INTEGER FUNCTION NF_GET_VAR1_REAL (NCID, VARID, INDEX, rval)
INTEGER FUNCTION NF_PUT_VAR1_DOUBLE(NCID, VARID, INDEX, DVAL)
INTEGER FUNCTION NF_GET_VAR1_DOUBLE(NCID, VARID, INDEX, dval)
INTEGER FUNCTION NF_PUT_VARA_TEXT (NCID, VARID, START, COUNT, TEXT)
INTEGER FUNCTION NF_GET_VARA_TEXT (NCID, VARID, START, COUNT, text)
INTEGER FUNCTION NF_PUT_VARA_INT1 (NCID, VARID, START, COUNT, I1VALS)
INTEGER FUNCTION NF_GET_VARA_INT1 (NCID, VARID, START, COUNT, i1vals)
INTEGER FUNCTION NF_PUT_VARA_INT2 (NCID, VARID, START, COUNT, I2VALS)
INTEGER FUNCTION NF_GET_VARA_INT2 (NCID, VARID, START, COUNT, i2vals)
INTEGER FUNCTION NF_PUT_VARA_INT (NCID, VARID, START, COUNT, IVALS)
INTEGER FUNCTION NF_GET_VARA_INT (NCID, VARID, START, COUNT, ivals)
INTEGER FUNCTION NF_PUT_VARA_REAL (NCID, VARID, START, COUNT, RVALS)
INTEGER FUNCTION NF_GET_VARA_REAL (NCID, VARID, START, COUNT, rvals)
INTEGER FUNCTION NF_PUT_VARA_DOUBLE(NCID, VARID, START, COUNT, DVALS)
INTEGER FUNCTION NF_GET_VARA_DOUBLE(NCID, VARID, START, COUNT, dvals)
INTEGER FUNCTION NF_PUT_VARS_TEXT (NCID, VARID, START, COUNT, STRIDE,
TEXT)
INTEGER FUNCTION NF_GET_VARS_TEXT (NCID, VARID, START, COUNT, STRIDE,
text)
INTEGER FUNCTION NF_PUT_VARS_INT1 (NCID, VARID, START, COUNT, STRIDE,
I1VALS)
INTEGER FUNCTION NF_GET_VARS_INT1 (NCID, VARID, START, COUNT, STRIDE,
i1vals)
INTEGER FUNCTION NF_PUT_VARS_INT2 (NCID, VARID, START, COUNT, STRIDE,
I2VALS)
INTEGER FUNCTION NF_GET_VARS_INT2 (NCID, VARID, START, COUNT, STRIDE,
i2vals)
INTEGER FUNCTION NF_PUT_VARS_INT (NCID, VARID, START, COUNT, STRIDE,
IVALS)
INTEGER FUNCTION NF_GET_VARS_INT (NCID, VARID, START, COUNT, STRIDE,
ivals)
INTEGER FUNCTION NF_PUT_VARS_REAL (NCID, VARID, START, COUNT, STRIDE,
RVALS)
INTEGER FUNCTION NF_GET_VARS_REAL (NCID, VARID, START, COUNT, STRIDE,
rvals)
INTEGER FUNCTION NF_PUT_VARS_DOUBLE(NCID, VARID, START, COUNT, STRIDE,
DVALS)
INTEGER FUNCTION NF_GET_VARS_DOUBLE(NCID, VARID, START, COUNT, STRIDE,
dvals)
INTEGER FUNCTION NF_PUT_VARM_TEXT (NCID, VARID, START, COUNT, STRIDE,
IMAP, TEXT)
INTEGER FUNCTION NF_GET_VARM_TEXT (NCID, VARID, START, COUNT, STRIDE,
IMAP, text)
INTEGER FUNCTION NF_PUT_VARM_INT1 (NCID, VARID, START, COUNT, STRIDE,
IMAP, I1VALS)
INTEGER FUNCTION NF_GET_VARM_INT1 (NCID, VARID, START, COUNT, STRIDE,
IMAP, i1vals)
INTEGER FUNCTION NF_PUT_VARM_INT2 (NCID, VARID, START, COUNT, STRIDE,
IMAP, I2VALS)
INTEGER FUNCTION NF_GET_VARM_INT2 (NCID, VARID, START, COUNT, STRIDE,
IMAP, i2vals)
INTEGER FUNCTION NF_PUT_VARM_INT (NCID, VARID, START, COUNT, STRIDE,
IMAP, IVALS)
INTEGER FUNCTION NF_GET_VARM_INT (NCID, VARID, START, COUNT, STRIDE,
IMAP, ivals)
INTEGER FUNCTION NF_PUT_VARM_REAL (NCID, VARID, START, COUNT, STRIDE,
IMAP, RVALS)
INTEGER FUNCTION NF_GET_VARM_REAL (NCID, VARID, START, COUNT, STRIDE,
IMAP, rvals)
INTEGER FUNCTION NF_PUT_VARM_DOUBLE(NCID, VARID, START, COUNT, STRIDE,
IMAP, DVALS)
INTEGER FUNCTION NF_GET_VARM_DOUBLE(NCID, VARID, START, COUNT, STRIDE,
IMAP, dvals)
INTEGER FUNCTION NF_INQ_ATT (NCID, VARID, NAME, xtype, len)
INTEGER FUNCTION NF_INQ_ATTID (NCID, VARID, NAME, attnum)
INTEGER FUNCTION NF_INQ_ATTTYPE (NCID, VARID, NAME, xtype)
INTEGER FUNCTION NF_INQ_ATTLEN (NCID, VARID, NAME, len)
INTEGER FUNCTION NF_INQ_ATTNAME (NCID, VARID, ATTNUM, name)
INTEGER FUNCTION NF_COPY_ATT (NCID_IN, VARID_IN, NAME,
NCID_OUT, VARID_OUT)
INTEGER FUNCTION NF_RENAME_ATT (NCID, VARID, CURNAME, NEWNAME)
INTEGER FUNCTION NF_DEL_ATT (NCID, VARID, NAME)
INTEGER FUNCTION NF_PUT_ATT_TEXT (NCID, VARID, NAME, LEN, TEXT)
INTEGER FUNCTION NF_GET_ATT_TEXT (NCID, VARID, NAME, text)
INTEGER FUNCTION NF_PUT_ATT_INT1 (NCID, VARID, NAME, XTYPE, LEN,
I1VALS)
INTEGER FUNCTION NF_GET_ATT_INT1 (NCID, VARID, NAME, i1vals)
INTEGER FUNCTION NF_PUT_ATT_INT2 (NCID, VARID, NAME, XTYPE, LEN,
I2VALS)
INTEGER FUNCTION NF_GET_ATT_INT2 (NCID, VARID, NAME, i2vals)
INTEGER FUNCTION NF_PUT_ATT_INT (NCID, VARID, NAME, XTYPE, LEN,
IVALS)
INTEGER FUNCTION NF_GET_ATT_INT (NCID, VARID, NAME, ivals)
INTEGER FUNCTION NF_PUT_ATT_REAL (NCID, VARID, NAME, XTYPE, LEN,
RVALS)
INTEGER FUNCTION NF_GET_ATT_REAL (NCID, VARID, NAME, rvals)
INTEGER FUNCTION NF_PUT_ATT_DOUBLE (NCID, VARID, NAME, XTYPE, LEN,
DVALS)
INTEGER FUNCTION NF_GET_ATT_DOUBLE (NCID, VARID, NAME, dvals)
INTEGER ATTNUM ! attribute number
INTEGER attnum ! returned attribute number
INTEGER CMODE ! NF_NOCLOBBER, NF_SHARE flags expression
INTEGER COUNT ! array of edge lengths of block of values
CHARACTER(*) CURNAME ! current name (before renaming)
INTEGER DIMID ! dimension ID
INTEGER dimid ! returned dimension ID
INTEGER DIMIDS ! list of dimension IDs
INTEGER dimids ! list of returned dimension IDs
DOUBLEPRECISION DVAL ! single data value
DOUBLEPRECISION dval ! returned single data value
DOUBLEPRECISION DVALS ! array of data values
DOUBLEPRECISION dvals ! array of returned data values
INTEGER FILLMODE ! NF_NOFILL or NF_FILL, for setting fill mode
INTEGER*1 I1VAL ! single data value
INTEGER*1 I1val ! returned single data value
INTEGER*1 I1VALS ! array of data values
INTEGER*1 i1vals ! array of returned data values
INTEGER*2 I2VAL ! single data value
INTEGER*2 i2val ! returned single data value
INTEGER*2 I2VALS ! array of data values
INTEGER*2 i2vals ! array of returned data values
INTEGER IMAP ! index mapping vector
INTEGER INDEX ! variable array index vector
INTEGER IVAL ! single data value
INTEGER ival ! returned single data value
INTEGER IVALS ! array of data values
INTEGER ivals ! array of returned data values
INTEGER LEN ! dimension or attribute length
INTEGER len ! returned dimension or attribute length
INTEGER MODE ! open mode, one of NF_WRITE or NF_NOWRITE
CHARACTER(*) NAME ! dimension, variable, or attribute name
CHARACTER(*) name ! returned dim, var, or att name
INTEGER natts ! returned number of attributes
INTEGER NCERR ! error returned from NF_xxx function call
INTEGER NCID ! netCDF ID of an open netCDF dataset
INTEGER ncid ! returned netCDF ID
INTEGER NCID_IN ! netCDF ID of open source netCDF dataset
INTEGER NCID_OUT ! netCDF ID of open destination netCDF dataset
INTEGER NDIMS ! number of dimensions
INTEGER ndims ! returned number of dimensions
CHARACTER(*) NEWNAME ! new name for dim, var, or att
INTEGER ngatts ! returned number of global attributes
INTEGER nvars ! returned number of variables
INTEGER old_mode ! previous fill mode, NF_NOFILL or NF_FILL,
CHARACTER(*) PATH ! name of netCDF dataset
REAL RVAL ! single data value
REAL rval ! returned single data value
REAL RVALS ! array of data values
REAL rvals ! array of returned data values
INTEGER START ! variable array indices of first value
INTEGER STRIDE ! variable array dimensional strides
CHARACTER(*) TEXT ! input text value
CHARACTER(*) text ! returned text value
INTEGER unlimdimid ! returned ID of unlimited dimension
INTEGER VARID ! variable ID
INTEGER varid ! returned variable ID
INTEGER VARID_IN ! variable ID
INTEGER VARID_OUT ! variable ID
INTEGER XTYPE ! external type: NF_BYTE, NF_CHAR, ... ,
INTEGER xtype ! returned external type
Index
*****
attributes, adding: See 1.4. (line 200)
big-endian: See 6.15. (line 5230)
checksum: See 6.13. (line 5080)
chunking: See 6.4. (line 4387)
chunksizes: See 6.4. (line 4387)
compiling with netCDF library: See 1.6. (line 279)
compound types, overview: See 5.6. (line 2977)
compression, setting parameters: See 6.10. (line 4837)
contiguous: See 6.4. (line 4387)
creating dataset: See 1.1. (line 37)
datasets, introduction: See 2.1. (line 320)
deflate: See 6.10. (line 4837)
dimensions, adding: See 1.4. (line 200)
endianness: See 6.15. (line 5230)
enum type: See 5.9. (line 3873)
fill: See 6.8. (line 4720)
fletcher32: See 6.13. (line 5080)
groups, overview: See 3. (line 1745)
HDF5 chunk cache <1>: See 6.7. (line 4650)
HDF5 chunk cache <2>: See 2.21. (line 1704)
HDF5 chunk cache: See 2.20. (line 1657)
HDF5 chunk cache, per-variable: See 6.6. (line 4579)
interface descriptions: See 2.2. (line 365)
linking to netCDF library: See 1.6. (line 279)
little-endian: See 6.15. (line 5230)
nc_get_chunk_cache: See 2.21. (line 1704)
nc_set_chunk_cache: See 2.20. (line 1657)
nc_set_var_chunk_cache: See 6.6. (line 4579)
NF__CREATE: See 2.6. (line 552)
NF__ENDDEF: See 2.13. (line 1082)
NF__OPEN: See 2.9. (line 822)
NF_ABORT: See 2.17. (line 1422)
NF_CLOSE: See 2.14. (line 1201)
NF_CLOSE, typical use: See 1.1. (line 37)
NF_COPY_ATT: See 7.5. (line 7568)
NF_CREATE: See 2.5. (line 459)
NF_CREATE, typical use: See 1.1. (line 37)
NF_CREATE_PAR: See 2.7. (line 678)
NF_DEF_COMPOUND: See 5.6.1. (line 3002)
NF_DEF_DIM: See 4.2. (line 2441)
NF_DEF_DIM, typical use: See 1.1. (line 37)
NF_DEF_ENUM: See 5.9.1. (line 3879)
NF_DEF_GRP: See 3.11. (line 2324)
NF_DEF_OPAQUE: See 5.8.1. (line 3768)
NF_DEF_VAR: See 6.3. (line 4281)
NF_DEF_VAR, typical use: See 1.1. (line 37)
NF_DEF_VAR_CHUNKING: See 6.4. (line 4387)
NF_DEF_VAR_DEFLATE: See 6.10. (line 4837)
NF_DEF_VAR_ENDIAN: See 6.15. (line 5230)
NF_DEF_VAR_FILL: See 6.8. (line 4720)
NF_DEF_VAR_FLETCHER32: See 6.13. (line 5080)
NF_DEF_VLEN <1>: See 5.7.2. (line 3545)
NF_DEF_VLEN: See 5.7.1. (line 3483)
NF_DEL_ATT: See 7.7. (line 7735)
NF_ENDDEF: See 2.12. (line 1029)
NF_ENDDEF, typical use: See 1.1. (line 37)
NF_FREE_VLEN: See 5.7.3. (line 3603)
NF_GET_ATT, typical use: See 1.2. (line 93)
NF_GET_ATT_ type: See 7.4. (line 7448)
nf_get_chunk_cache: See 6.7. (line 4650)
NF_GET_VAR, typical use: See 1.2. (line 93)
NF_GET_VAR1_ type: See 6.24. (line 6231)
NF_GET_VAR_ type: See 6.25. (line 6332)
NF_GET_VARA_ type: See 6.26. (line 6426)
NF_GET_VARM_ type: See 6.28. (line 6684)
NF_GET_VARS_ type: See 6.27. (line 6555)
NF_GET_VLEN_ELEMENT: See 5.7.5. (line 3694)
NF_INQ Family: See 2.15. (line 1248)
NF_INQ, typical use: See 1.3. (line 134)
NF_INQ_ATT Family: See 7.3. (line 7338)
NF_INQ_ATTNAME, typical use: See 1.3. (line 134)
NF_INQ_COMPOUND: See 5.6.4. (line 3256)
NF_INQ_COMPOUND_FIELD: See 5.6.5. (line 3347)
NF_INQ_COMPOUND_FIELDDIM_SIZES: See 5.6.5. (line 3347)
NF_INQ_COMPOUND_FIELDINDEX: See 5.6.5. (line 3347)
NF_INQ_COMPOUND_FIELDNAME: See 5.6.5. (line 3347)
NF_INQ_COMPOUND_FIELDNDIMS: See 5.6.5. (line 3347)
NF_INQ_COMPOUND_FIELDOFFSET: See 5.6.5. (line 3347)
NF_INQ_COMPOUND_FIELDTYPE: See 5.6.5. (line 3347)
NF_INQ_COMPOUND_NAME: See 5.6.4. (line 3256)
NF_INQ_COMPOUND_NFIELDS: See 5.6.4. (line 3256)
NF_INQ_COMPOUND_SIZE: See 5.6.4. (line 3256)
NF_INQ_DIM Family: See 4.4. (line 2561)
NF_INQ_DIMID: See 4.3. (line 2508)
NF_INQ_DIMID, typical use: See 1.2. (line 93)
NF_INQ_DIMIDS: See 3.4. (line 1931)
NF_INQ_ENUM: See 5.9.3. (line 4024)
NF_INQ_ENUM_IDENT: See 5.9.5. (line 4141)
nf_inq_enum_member: See 5.9.4. (line 4083)
NF_INQ_FORMAT: See 2.15. (line 1248)
NF_INQ_GRP_PARENT <1>: See 3.10. (line 2264)
NF_INQ_GRP_PARENT <2>: See 3.9. (line 2205)
NF_INQ_GRP_PARENT: See 3.8. (line 2151)
NF_INQ_GRPNAME: See 3.6. (line 2037)
NF_INQ_GRPNAME_FULL: See 3.7. (line 2093)
NF_INQ_GRPNAME_LEN: See 3.5. (line 1988)
NF_INQ_GRPS: See 3.2. (line 1828)
NF_INQ_LIBVERS: See 2.4. (line 432)
NF_INQ_NATTS: See 2.15. (line 1248)
NF_INQ_NCID: See 3.1. (line 1775)
NF_INQ_NDIMS: See 2.15. (line 1248)
NF_INQ_NVARS: See 2.15. (line 1248)
NF_INQ_OPAQUE: See 5.8.2. (line 3821)
NF_INQ_TYPE: See 5.4. (line 2828)
NF_INQ_TYPEID: See 5.3. (line 2782)
NF_INQ_TYPEIDS: See 5.2. (line 2741)
NF_INQ_UNLIMDIM: See 2.15. (line 1248)
NF_INQ_USER_TYPE: See 5.5. (line 2911)
NF_INQ_VAR family: See 6.18. (line 5436)
NF_INQ_VAR_CHUNKING: See 6.5. (line 4518)
NF_INQ_VAR_DEFLATE: See 6.11. (line 4959)
NF_INQ_VAR_ENDIAN: See 6.16. (line 5332)
NF_INQ_VAR_FILL: See 6.9. (line 4791)
NF_INQ_VAR_FLETCHER32: See 6.14. (line 5175)
NF_INQ_VAR_SZIP: See 6.12. (line 5027)
NF_INQ_VARID: See 6.17. (line 5387)
NF_INQ_VARID, typical use: See 1.2. (line 93)
NF_INQ_VARIDS: See 3.3. (line 1881)
NF_INSERT_ARRAY_COMPOUND: See 5.6.3. (line 3161)
NF_INSERT_COMPOUND: See 5.6.2. (line 3086)
NF_INSERT_ENUM: See 5.9.2. (line 3953)
NF_OPEN: See 2.8. (line 764)
NF_OPEN_PAR: See 2.10. (line 902)
NF_PUT_ATT, typical use: See 1.1. (line 37)
NF_PUT_ATT_ type: See 7.2. (line 7207)
NF_PUT_VAR, typical use: See 1.1. (line 37)
NF_PUT_VAR1_ type: See 6.19. (line 5537)
NF_PUT_VAR_ type: See 6.20. (line 5641)
NF_PUT_VARA_ type: See 6.21. (line 5751)
NF_PUT_VARM_ type: See 6.23. (line 6029)
NF_PUT_VARS_ type: See 6.22. (line 5892)
NF_PUT_VLEN_ELEMENT: See 5.7.4. (line 3639)
NF_REDEF: See 2.11. (line 986)
NF_RENAME_ATT: See 7.6. (line 7665)
NF_RENAME_DIM: See 4.5. (line 2639)
NF_RENAME_VAR: See 6.31. (line 7032)
NF_SET_DEFAULT_FORMAT: See 2.19. (line 1586)
NF_SET_FILL: See 2.18. (line 1477)
NF_STRERROR: See 2.3. (line 389)
NF_SYNC: See 2.16. (line 1325)
NF_VAR_PAR_ACCESS: See 6.32. (line 7091)
NF_VAR_PAR_ACCESS, example: See 6.32. (line 7091)
opaque type: See 5.8. (line 3753)
reading dataset with unknown names: See 1.3. (line 134)
reading datasets with known names: See 1.2. (line 93)
user defined types: See 5. (line 2703)
user defined types, overview: See 5.1. (line 2706)
variable length array type, overview: See 5. (line 2703)
variable length arrays: See 5.7. (line 3444)
variables, adding: See 1.4. (line 200)
variables, checksum: See 6.13. (line 5080)
variables, chunking: See 6.4. (line 4387)
variables, contiguous: See 6.4. (line 4387)
variables, endian: See 6.15. (line 5230)
variables, fill: See 6.8. (line 4720)
variables, fletcher32: See 6.13. (line 5080)
variables, setting deflate: See 6.10. (line 4837)
VLEN: See 5.7. (line 3444)
VLEN, defining <1>: See 5.7.3. (line 3603)
VLEN, defining <2>: See 5.7.2. (line 3545)
VLEN, defining: See 5.7.1. (line 3483)
