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<title>XYZ2GRD</title>
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<h1 align=center>XYZ2GRD</h1>
<a href="#NAME">NAME</a><br>
<a href="#SYNOPSIS">SYNOPSIS</a><br>
<a href="#DESCRIPTION">DESCRIPTION</a><br>
<a href="#OPTIONS">OPTIONS</a><br>
<a href="#GRID VALUES PRECISION">GRID VALUES PRECISION</a><br>
<a href="#GRID FILE FORMATS">GRID FILE FORMATS</a><br>
<a href="#GEOGRAPHICAL AND TIME COORDINATES">GEOGRAPHICAL AND TIME COORDINATES</a><br>
<a href="#EXAMPLES">EXAMPLES</a><br>
<a href="#SEE ALSO">SEE ALSO</a><br>
<hr>
<a name="NAME"></a>
<h2>NAME</h2>
<p style="margin-left:11%; margin-top: 1em">xyz2grd −
Converting an ASCII or binary table to grid file format</p>
<a name="SYNOPSIS"></a>
<h2>SYNOPSIS</h2>
<p style="margin-left:11%; margin-top: 1em"><b>xyz2grd</b>
<i>xyzfile</i> <b>−G</b><i>grdfile</i>
<b>−I</b><i>xinc</i>[<i>unit</i>][<b>=</b>|<b>+</b>][/<i>yinc</i>[<i>unit</i>][<b>=</b>|<b>+</b>]]
<b>−R</b><i>west</i>/<i>east</i>/<i>south</i>/<i>north</i>[<b>r</b>]
[ <b>−A</b>[<b>n|z|u|l</b>] ] [
<b>−D</b><i>xname</i>/<i>yname</i>/<i>zname</i>/<i>scale</i>/<i>offset</i>/<i>title</i>/<i>remark</i>
] [ <b>−E</b>[<i>nodata</i>] ] [ <b>−F</b> ] [
<b>−H</b>[<b>i</b>][<i>nrec</i>] ] [
<b>−N</b><i>nodata</i> ] [
<b>−S</b>[<i>zfile</i>] ] [ <b>−V</b> ] [
<b>−Z</b>[<i>flags</i>] ] [
<b>−:</b>[<b>i</b>|<b>o</b>] ] [
<b>−bi</b>[<b>s</b>|<b>S</b>|<b>d</b>|<b>D</b>[<i>ncol</i>]|<b>c</b>[<i>var1</i><b>/</b><i>...</i>]]
] [ <b>−f</b><i>colinfo</i> ]</p>
<a name="DESCRIPTION"></a>
<h2>DESCRIPTION</h2>
<p style="margin-left:11%; margin-top: 1em"><b>xyz2grd</b>
reads a z or xyz table and creates a binary grid file.
<b>xyz2grd</b> will report if some of the nodes are not
filled in with data. Such unconstrained nodes are set to a
value specified by the user [Default is NaN]. Nodes with
more than one value will be set to the average value. As an
option (using <b>−Z</b>), a 1-column z-table may be
read assuming all nodes are present (z-tables can be in
organized in a number of formats, see <b>−Z</b>
below.) <i><br>
[xy]zfile</i></p>
<p style="margin-left:22%;">ASCII [or binary] file holding
z or (x,y,z) values. xyz triplets do not have to be sorted
(for binary triplets, see <b>−b</b>). 1-column z
tables must be sorted and the <b>−Z</b> must be
set).</p>
<table width="100%" border=0 rules="none" frame="void"
cellspacing="0" cellpadding="0">
<tr valign="top" align="left">
<td width="11%"></td>
<td width="3%">
<p style="margin-top: 1em" valign="top"><b>−G</b></p> </td>
<td width="8%"></td>
<td width="78%">
<p style="margin-top: 1em" valign="top"><i>grdfile</i> is
the name of the binary output grid file. (See GRID FILE
FORMAT below.)</p></td>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="3%">
<p style="margin-top: 1em" valign="top"><b>−I</b></p> </td>
<td width="8%"></td>
<td width="78%">
<p style="margin-top: 1em" valign="top"><i>x_inc</i> [and
optionally <i>y_inc</i>] is the grid spacing. Optionally,
append a suffix modifier. <b>Geographical (degrees)
coordinates</b>: Append <b>m</b> to indicate arc minutes or
<b>c</b> to indicate arc seconds. If one of the units
<b>e</b>, <b>k</b>, <b>i</b>, or <b>n</b> is appended
instead, the increment is assumed to be given in meter, km,
miles, or nautical miles, respectively, and will be
converted to the equivalent degrees longitude at the middle
latitude of the region (the conversion depends on
<b><A HREF="gmtdefaults.html#ELLIPSOID">ELLIPSOID</A></b>). If /<i>y_inc</i> is given but set to 0 it
will be reset equal to <i>x_inc</i>; otherwise it will be
converted to degrees latitude. <b>All coordinates</b>: If
<b>=</b> is appended then the corresponding max <i>x</i>
(<i>east</i>) or <i>y</i> (<i>north</i>) may be slightly
adjusted to fit exactly the given increment [by default the
increment may be adjusted slightly to fit the given domain].
Finally, instead of giving an increment you may specify the
<i>number of nodes</i> desired by appending <b>+</b> to the
supplied integer argument; the increment is then
recalculated from the number of nodes and the domain. The
resulting increment value depends on whether you have
selected a gridline-registered or pixel-registered grid; see
Appendix B for details. Note: if
<b>−R</b><i>grdfile</i> is used then grid spacing has
already been initialized; use <b>−I</b> to override
the values.</p></td>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="3%">
<p style="margin-top: 1em" valign="top"><b>−R</b></p> </td>
<td width="8%"></td>
<td width="78%">
<p style="margin-top: 1em" valign="top"><i>xmin</i>,
<i>xmax</i>, <i>ymin</i>, and <i>ymax</i> specify the Region
of interest. For geographic regions, these limits correspond
to <i>west, east, south,</i> and <i>north</i> and you may
specify them in decimal degrees or in
[+-]dd:mm[:ss.xxx][W|E|S|N] format. Append <b>r</b> if lower
left and upper right map coordinates are given instead of
w/e/s/n. The two shorthands <b>−Rg</b> and
<b>−Rd</b> stand for global domain (0/360 and
-180/+180 in longitude respectively, with -90/+90 in
latitude). Alternatively, specify the name of an existing
grid file and the <b>−R</b> settings (and grid
spacing, if applicable) are copied from the grid. For
calendar time coordinates you may either give (a) relative
time (relative to the selected <b><A HREF="gmtdefaults.html#TIME_EPOCH">TIME_EPOCH</A></b> and in the
selected <b><A HREF="gmtdefaults.html#TIME_UNIT">TIME_UNIT</A></b>; append <b>t</b> to
<b>−JX</b>|<b>x</b>), or (b) absolute time of the form
[<i>date</i>]<b>T</b>[<i>clock</i>] (append <b>T</b> to
<b>−JX</b>|<b>x</b>). At least one of <i>date</i> and
<i>clock</i> must be present; the <b>T</b> is always
required. The <i>date</i> string must be of the form
[-]yyyy[-mm[-dd]] (Gregorian calendar) or yyyy[-Www[-d]]
(ISO week calendar), while the <i>clock</i> string must be
of the form hh:mm:ss[.xxx]. The use of delimiters and their
type and positions must be exactly as indicated (however,
input, output and plot formats are customizable; see
<b><A HREF="gmtdefaults.html">gmtdefaults</A></b>).</p> </td>
</table>
<a name="OPTIONS"></a>
<h2>OPTIONS</h2>
<table width="100%" border=0 rules="none" frame="void"
cellspacing="0" cellpadding="0">
<tr valign="top" align="left">
<td width="11%"></td>
<td width="3%">
<p style="margin-top: 1em" valign="top"><b>−A</b></p> </td>
<td width="4%"></td>
<td width="82%">
<p style="margin-top: 1em" valign="top">Add up multiple
values that belong to the same node (same as
<b>−Az</b>). Append <b>n</b> to simply count the
number of data points that were assigned to each node.
Append <b>l</b> or <b>u</b> to find the lowest (minimum) or
upper (maximum) value at each node, respectively. [Default
(no <b>−A</b> option) will calculate mean value].
Ignored if <b>−Z</b> is given.</p></td>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="3%">
<p style="margin-top: 1em" valign="top"><b>−D</b></p> </td>
<td width="4%"></td>
<td width="82%">
<p style="margin-top: 1em" valign="top">Give values for
<i>xname, yname, zname, scale, offset, title,</i> and
<i>remark</i>. To leave some of these values untouched,
specify = as the value. Alternatively, to allow
"/" to be part of one of the values, use any
non-alphanumeric character (and not the equal sign) as
separator by both starting and ending with it. For example:
<b>−D</b>:<i>xname</i>:<i>yname</i>:<i>zname</i>:<i>scale</i>:<i>offset</i>:<i>title</i>:<i>remark</i>:</p> </td>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="3%">
<p style="margin-top: 1em" valign="top"><b>−E</b></p> </td>
<td width="4%"></td>
<td width="82%">
<p style="margin-top: 1em" valign="top">Convert an ESRI
ArcInfo ASCII interchange grid format file to a <b><A HREF="GMT.html">GMT</A></b>
grid. Append <i>nodata</i> which is a data value that should
be set to NaN in the grid [If we find the optional 6th
record in the file we will use it instead]. The values
normally given by <b>−R</b>, <b>−I</b>, and
<b>−F</b> are determined from the ESRI header
instead.</p> </td>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="3%">
<p style="margin-top: 1em" valign="top"><b>−F</b></p> </td>
<td width="4%"></td>
<td width="82%">
<p style="margin-top: 1em" valign="top">Force pixel node
registration [Default is gridline registration]. (Node
registrations are defined in <b><A HREF="GMT.html">GMT</A></b> Cookbook Appendix B
on grid file formats.)</p></td>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="3%">
<p style="margin-top: 1em" valign="top"><b>−H</b></p> </td>
<td width="4%"></td>
<td width="82%">
<p style="margin-top: 1em" valign="top">Input file(s) has
header record(s). If used, the default number of header
records is <b><A HREF="gmtdefaults.html#N_HEADER_RECS">N_HEADER_RECS</A></b>. Use <b>−Hi</b> if
only input data should have header records [Default will
write out header records if the input data have them]. Blank
lines and lines starting with # are always skipped. Not used
with binary data.</p></td>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="3%">
<p style="margin-top: 1em" valign="top"><b>−N</b></p> </td>
<td width="4%"></td>
<td width="82%">
<p style="margin-top: 1em" valign="top">No data. Set nodes
with no input xyz triplet to this value [Default is NaN].
For z-tables, this option is used to replace z-values that
equal <i>nodata</i> with NaN.</p></td>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="3%">
<p style="margin-top: 1em" valign="top"><b>−S</b></p> </td>
<td width="4%"></td>
<td width="82%">
<p style="margin-top: 1em" valign="top">Swap the byte-order
of the input only. No grid file is produced. You must also
supply the <b>−Z</b> option. The output is written to
<i>zfile</i> (or stdout if not supplied).</p></td>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="3%">
<p style="margin-top: 1em" valign="top"><b>−V</b></p> </td>
<td width="4%"></td>
<td width="82%">
<p style="margin-top: 1em" valign="top">Selects verbose
mode, which will send progress reports to stderr [Default
runs "silently"].</p></td>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="3%">
<p style="margin-top: 1em" valign="top"><b>−Z</b></p> </td>
<td width="4%"></td>
<td width="82%">
<p style="margin-top: 1em" valign="top">Read a 1-column
ASCII [or binary] table. This assumes that all the nodes are
present and sorted according to specified ordering
convention contained in <i>flags</i>. If incoming data
represents rows, make <i>flags</i> start with <b>T</b>(op)
if first row is y = ymax or <b>B</b>(ottom) if first row is
y = ymin. Then, append <b>L</b> or <b>R</b> to indicate that
first element is at left or right end of row. Likewise for
column formats: start with <b>L</b> or <b>R</b> to position
first column, and then append <b>T</b> or <b>B</b> to
position first element in a row. For gridline registered
grids: If data are periodic in x but the incoming data do
not contain the (redundant) column at x = xmax, append
<b>x</b>. For data periodic in y without redundant row at y
= ymax, append <b>y</b>. Append <b>s</b><i>n</i> to skip the
first <i>n</i> number of bytes (probably a header). If the
byte-order needs to be swapped, append <b>w</b>. Select one
of several data types (all binary except <b>a</b>):</p></td>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="3%"></td>
<td width="4%"></td>
<td width="82%">
<p valign="top"><b>A</b> ASCII representation of one or
more floating point values per record</p></td>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="3%"></td>
<td width="4%"></td>
<td width="82%">
<p valign="top"><b>a</b> ASCII representation of a single
item per record</p></td>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="3%"></td>
<td width="4%"></td>
<td width="82%">
<p valign="top"><b>c</b> signed 1-byte character</p></td>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="3%"></td>
<td width="4%"></td>
<td width="82%">
<p valign="top"><b>u</b> unsigned 1-byte character</p></td>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="3%"></td>
<td width="4%"></td>
<td width="82%">
<p valign="top"><b>h</b> short 2-byte integer</p></td>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="3%"></td>
<td width="4%"></td>
<td width="82%">
<p valign="top"><b>i</b> 4-byte integer</p></td>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="3%"></td>
<td width="4%"></td>
<td width="82%">
<p valign="top"><b>l</b> long (4- or 8-byte) integer
[architecture-dependent!]</p> </td>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="3%"></td>
<td width="4%"></td>
<td width="82%">
<p valign="top"><b>f</b> 4-byte floating point single
precision</p> </td>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="3%"></td>
<td width="4%"></td>
<td width="82%">
<p valign="top"><b>d</b> 8-byte floating point double
precision</p> </td>
</table>
<p style="margin-left:22%; margin-top: 1em">Default format
is scanline orientation of ASCII numbers:
<b>−ZTLa</b>. Note that <b>−Z</b> only applies
to 1-column input. The difference between <b>A</b> and
<b>a</b> is that the latter can decode both
<i>date</i>T<i>clock</i> and <i>ddd:mm:ss[.xx]</i> formats
while the former is strictly for regular floating point
values.</p>
<table width="100%" border=0 rules="none" frame="void"
cellspacing="0" cellpadding="0">
<tr valign="top" align="left">
<td width="11%"></td>
<td width="4%">
<p style="margin-top: 1em" valign="top"><b>−:</b></p> </td>
<td width="7%"></td>
<td width="78%">
<p style="margin-top: 1em" valign="top">Toggles between
(longitude,latitude) and (latitude,longitude) input and/or
output. [Default is (longitude,latitude)]. Append <b>i</b>
to select input only or <b>o</b> to select output only.
[Default affects both].</p></td>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="4%">
<p style="margin-top: 1em" valign="top"><b>−bi</b></p> </td>
<td width="7%"></td>
<td width="78%">
<p style="margin-top: 1em" valign="top">Selects binary
input. Append <b>s</b> for single precision [Default is
<b>d</b> (double)]. Uppercase <b>S</b> or <b>D</b> will
force byte-swapping. Optionally, append <i>ncol</i>, the
number of columns in your binary input file if it exceeds
the columns needed by the program. Or append <b>c</b> if the
input file is netCDF. Optionally, append
<i>var1</i><b>/</b><i>var2</i><b>/</b><i>...</i> to specify
the variables to be read. [Default is 3 input columns]. This
option only applies to xyz input files; see <b>−Z</b>
for z tables.</p></td>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="4%">
<p style="margin-top: 1em" valign="top"><b>−f</b></p> </td>
<td width="7%"></td>
<td width="78%">
<p style="margin-top: 1em" valign="top">Special formatting
of input and/or output columns (time or geographical data).
Specify <b>i</b> or <b>o</b> to make this apply only to
input or output [Default applies to both]. Give one or more
columns (or column ranges) separated by commas. Append
<b>T</b> (absolute calendar time), <b>t</b> (relative time
in chosen <b><A HREF="gmtdefaults.html#TIME_UNIT">TIME_UNIT</A></b> since <b><A HREF="gmtdefaults.html#TIME_EPOCH">TIME_EPOCH</A></b>),
<b>x</b> (longitude), <b>y</b> (latitude), or <b>f</b>
(floating point) to each column or column range item.
Shorthand <b>−f</b>[<b>i</b>|<b>o</b>]<b>g</b> means
<b>−f</b>[<b>i</b>|<b>o</b>]0<b>x</b>,1<b>y</b>
(geographic coordinates).</p></td>
</table>
<a name="GRID VALUES PRECISION"></a>
<h2>GRID VALUES PRECISION</h2>
<p style="margin-left:11%; margin-top: 1em">Regardless of
the precision of the input data, GMT programs that create
grid files will internally hold the grids in 4-byte floating
point arrays. This is done to conserve memory and
furthermore most if not all real data can be stored using
4-byte floating point values. Data with higher precision
(i.e., double precision values) will lose that precision
once GMT operates on the grid or writes out new grids. To
limit loss of precision when processing data you should
always consider normalizing the data prior to
processing.</p>
<a name="GRID FILE FORMATS"></a>
<h2>GRID FILE FORMATS</h2>
<p style="margin-left:11%; margin-top: 1em">By default
<b><A HREF="GMT.html">GMT</A></b> writes out grid as single precision floats in a
COARDS-complaint netCDF file format. However, <b><A HREF="GMT.html">GMT</A></b> is
able to produce grid files in many other commonly used grid
file formats and also facilitates so called
"packing" of grids, writing out floating point
data as 2- or 4-byte integers. To specify the precision,
scale and offset, the user should add the suffix
<b>=</b><i>id</i>[<b>/</b><i>scale</i><b>/</b><i>offset</i>[<b>/</b><i>nan</i>]],
where <i>id</i> is a two-letter identifier of the grid type
and precision, and <i>scale</i> and <i>offset</i> are
optional scale factor and offset to be applied to all grid
values, and <i>nan</i> is the value used to indicate missing
data. See <b><A HREF="grdreformat.html">grdreformat</A></b>(1) and Section 4.17 of the GMT
Technical Reference and Cookbook for more information.</p>
<p style="margin-left:11%; margin-top: 1em">When writing a
netCDF file, the grid is stored by default with the variable
name "z". To specify another variable name
<i>varname</i>, append <b>?</b><i>varname</i> to the file
name. Note that you may need to escape the special meaning
of <b>?</b> in your shell program by putting a backslash in
front of it, or by placing the filename and suffix between
quotes or double quotes.</p>
<a name="GEOGRAPHICAL AND TIME COORDINATES"></a>
<h2>GEOGRAPHICAL AND TIME COORDINATES</h2>
<p style="margin-left:11%; margin-top: 1em">When the output
grid type is netCDF, the coordinates will be labeled
"longitude", "latitude", or
"time" based on the attributes of the input data
or grid (if any) or on the <b>−f</b> or
<b>−R</b> options. For example, both <b>−f0x
−f1t</b> and <b>−R</b>90w/90e/0t/3t will result
in a longitude/time grid. When the x, y, or z coordinate is
time, it will be stored in the grid as relative time since
epoch as specified by <b><A HREF="gmtdefaults.html#TIME_UNIT">TIME_UNIT</A></b> and <b><A HREF="gmtdefaults.html#TIME_EPOCH">TIME_EPOCH</A></b>
in the .gmtdefaults file or on the command line. In
addition, the <b>unit</b> attribute of the time variable
will indicate both this unit and epoch.</p>
<a name="EXAMPLES"></a>
<h2>EXAMPLES</h2>
<p style="margin-left:11%; margin-top: 1em">To create a
grid file from the ASCII data in hawaii_grv.xyz, use</p>
<p style="margin-left:11%; margin-top: 1em"><b>xyz2grd</b>
hawaii_grv.xyz
<b>−D</b>degree/degree/mGal/1/0/"Hawaiian
Gravity"/"GRS-80 Ellipsoid used"
<b>−G</b>hawaii_grv_new.grd
<b>−R</b>198/208/18/25 <b>−I</b>5<b>m
−V</b></p>
<p style="margin-left:11%; margin-top: 1em">To create a
grid file from the raw binary (3-column, single-precision)
scanline-oriented data raw.b, use</p>
<p style="margin-left:11%; margin-top: 1em"><b>xyz2grd</b>
raw.b <b>−D</b>m/m/m/1/0/=/= <b>−G</b>raw.grd
<b>−R</b>0/100/0/100 <b>−I</b>1 <b>−V
−Z −b</b>3</p>
<p style="margin-left:11%; margin-top: 1em">To make a grid
file from the raw binary USGS DEM (short integer)
scanline-oriented data topo30. on the NGDC global relief
Data CD-ROM, with values of -9999 indicate missing data, one
must on some machine reverse the byte-order. On such
machines (like Sun), use</p>
<p style="margin-left:11%; margin-top: 1em"><b>xyz2grd</b>
topo30. <b>−D</b>m/m/m/1/0/=/=
<b>−G</b>ustopo.grd <b>−R</b>234/294/24/50
<b>−I</b>30c <b>−N</b>-9999 <b>−B
−ZTLhw</b></p>
<p style="margin-left:11%; margin-top: 1em">Say you have
received a binary file with 4-byte floating points that were
written on a machine of different byte-order than yours. You
can swap the byte-order with</p>
<p style="margin-left:11%; margin-top: 1em"><b>xyz2grd</b>
floats.bin <b>−S</b>new_floats.bin <b>−V
−Zf</b></p>
<a name="SEE ALSO"></a>
<h2>SEE ALSO</h2>
<p style="margin-left:11%; margin-top: 1em"><i><A HREF="GMT.html">GMT</A></i>(1),
<i><A HREF="grd2xyz.html">grd2xyz</A></i>(1), <i><A HREF="grdedit.html">grdedit</A></i>(1)</p>
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