.help packages Aug83 "IRAF Package Structure"
.sh
1. Introduction

    This document is a first attempt to fully define the decomposition of
the IRAF system and applications software into packages.  The functions
to be supplied by each package are summarized.  The names of some of the
individual packages are likely to change.  Given the package structure
detailed below, the IRAF root menu would appear as follows:

.nf
cl> ?
    artdata       digiphot      help          lists         system
    astrometry    dtoi          images        nsurfbrt      twodspec
    database      filterphot    imred         onedspec      utilities
    dataio        focas         language      softools      
.fi

.sh
2. Top Level Packages

    If the command HELP is typed without any arguments, the default action
is to print out a summary of the contents of the current package, giving
a one line description of the function of each package.  The nonspecific
HELP documentation for the root package, i.e., the package "clpackage",
might appear as follows:

.nf
    artdata	artificial data generation
    astrometry	astrometric routines
    database	database management utilities
    dataio	data format conversions (FITS, card image, etc.)
    digiphot	digital stellar photometry
    dtoi	density to intensity transformations
    filterphot	filter photometry reductions
    focas	faint object classification and analysis
    help	online help utility (not a package)
    images	general image processing and display
    imred	image reductions
    language	language stuff (task, kill, set, etc.)
    lists	list processing utilities
    onedspec	one dimensional spectra
    softools	software tools
    nsurfbrt	new surface brightness package
    system	system utilities (files etc.)
    twodspec	two dimensional spectra
    utilities	miscellaneous utilities
.fi

.sh
3. Notes on Individual Packages

    Each top level package may contain any number of tasks or second level
packages.  As we proceed lower into the hierarchy, the tasks and packages
become more specific in the type of data they deal with.  An individual
task should not be duplicated in several packages; a task which is needed
in more than one package should be defined at a higher level in the hierarchy.
Examples of such general purpose tasks include HELP, and the tasks in the
LISTS and SYSTEM packages.

.sh
3.1 Package ARTDATA

    The ARTDATA package shall provide routines for the generation of
artificial data.  The principal use of artificial data is for testing
reduction and analysis software, making objective comparison of algorithms
and packages possible, and quantifying the non-systematic errors of such
software.  The package shall meet the following requirements:
.ls 4
.ls (1)
It shall be possible to model the noise functions of various detectors.
.le
.ls (2)
It shall be possible to add noise to an image, by randomly sampling
a gaussian or poisson distribution, the width of which is some function
of pixel intensity (this is determined by the noise model).
.le
.ls (3)
It shall be possible to analytically model line and point spread functions.
.le
.ls (4)
It shall be possible to model the characteristic curve of photographic
plates (and possibly other nonlinear detectors).
.le
.ls (5)
It shall be possible to generate diagnostic rasters, including constant
rasters, gaussian or poisson noise rasters with a constant noise function,
multidimensional smooth distributions (i.e., two dimensional gaussians, 
ellipses, and legendre surfaces), stepwedge, stairstep, ramps, and so on.
.le
.ls (6)
It shall be possible to generate artificial starfields, optionally including
scaled galaxy images randomly selected from an digital library, wherein
the noise function, luminosity function, point spread function, spatial
distribution, and non-linearity are all modeled.
.le
.ls (7)
It shall be possible to generate artificial one and two dimensional spectra,
wherein the noise function, line spread function, line list, dispersion,
and geometric distortions (pincushion, s, and tilt) are all modeled.
.le
.ls (8)
All model parameters used to generate an artificial image shall be saved
in such a form that they can be compared with the parameters derived by
reduction and analysis software to compute errors.  It shall be possible
to export model parameters on a FITS or cardimage tape, along with the
artificial image.
.le
.le

.ks
.nf
Subpackages:

    artstars		artificial starfield generation
    artspec		artificial 1&2 dim spectra generation
.fi
.ke

.sh
3.2 Package ASTROMETRY

    A collection of routines for performing astrometry.  Coordinate
input generally comes from other packages; the astrometry routines
determine the image coordinate system and transform object coordinates
in pixels into other coordinate systems.  The following functions shall
be provided:
.ls
.ls (1)
It shall be possible to determine the coordinates of an object or objects
within an image by fitting gaussians or discrete psf marginal profiles to
the marginal profiles of the image.
.le
.ls (2)
It shall be possible to determine the transformation from pixel to user
coordinates for an image given the pixel and user coordinates of 1, 2,
or 3 or more stars in the image.  The computation of the coordinate
transformation shall be decoupled from the generation of object coordinates.
It may be desirable to provide several types of transformations to model
the geometric distortions of various detectors.
.le
.ls (3)
The transformation parameters shall be saved in such a form that they
can be edited by the user or supplied by external programs.
.le
.ls (4)
It shall be possible to apply the coordinate transformation to convert
a list of coordinates from one coordinate system to another,
given the input list, the names of the input and output coordinate systems,
and the transformation descriptor.
.le
.le

.sh
3.3 Package DATABASE

    The IRAF database management utilities.  Routines shall be included for
inspecting, editing, copying, and otherwise manipulating the contents
of datafiles.  The IRAF system does not yet have a database capability;
the requirements for the DATABASE package will be defined when the
form of the IRAF database facilities have been worked out.

.sh
3.4 Package DATAIO

    Routines for data format conversion.  The essential thing here is
format conversion; although files will often be read or written to magtape,
we should not build conversion routines so that they work only on magtape
devices.  As networking becomes more widely used on our systems, we will
wish to use the same conversion routines to read and write data transmitted
electronically between machines.  DATAIO shall provide the following
capabilities:
.ls
.ls (1)
It shall be possible to convert a FITS file into an IRAF imagefile,
and vice versa.
.le
.ls (2)
It shall be possible to convert a PDS file into an IRAF imagefile.
.le
.ls (3)
It shall be possible to convert a CAMERA file into an IRAF imagefile.
.le
.ls (4)
It shall be possible to convert a card image file into a text file,
and vice versa.
.le
.ls (5)
It shall be possible to convert a binary file containing only text into
a text file, and vice versa.
.le
.ls (6)
It shall be possible to copy a binary file, changing only the blocking
factor.
.le
.ls (7)
Each conversion routine shall be able to operate on either magtape
resident or disk resident files (this capability is already provided
by the IRAF magtape i/o interface).
.le
.le

Note that function (6) in combination with requirement (7) provides a
means of copying a file from magtape to disk or vice versa, or from one
tape drive to another.  In the process the tape record size and density
may be changed if desired.

The conversion routines for FITS, PDS, and CAMERA formats may involve
some loss of information, at least initially.  The problem is that these
are different image formats, with different image headers, and it is
not always possible to preserve all fields of the header across a
transformation.  The following additional requirements should be
met eventually, but need not be addressed in the first implementation:
.ls
.ls (8)
The image format conversion routines shall permit a user defined mapping
of fields in the input header to fields in the output header.  In the case
of the FITS and IRAF imagefile image headers, it shall be possible for the
user to define additional fields beyond those in the standard header.
The name and datatype of the two fields in a mapping need not be unique.
.le
.ls (9)
When converting from an external image format into the IRAF imagefile
format, blank or indefinite pixels shall be replaced by values which
approximate the underlying distribution.  These values may be artificially
generated if necessary (i.e., by interpolation).  The coordinates of each
bad pixel shall be added to the bad pixel list for the image.
.le
.le

Most IRAF applications code will work only on the standard IRAF data
structures.  The user is expected to use the DATAIO routines to get data
into the system, and to convert data for export.  Applications which
reduce data from instruments with unique data formats may need to provide
special conversion routines.  DATAIO will provide conversion routines only
for data formats which provide data for more than one package.

.sh
3.5 Package DIGIPHOT

    A package of routines for digital stellar photometry, in both crowded
and uncrowded fields.  A range of routines shall be provided, ranging from
simple aperture photometry of sparse or moderately crowded fields, though
single star psf-fitting techniques, to simultaneous surface fits of
blended images.
.ls
.ls (1)
It shall be possible to perform aperture photometry on linearized images
via fractional pixel techniques, using circular apertures and annuli.  
It is desirable to be able to perform aperture photometry using elliptical
apertures and annuli, but this is not a requirement.
.le
.ls (2)
It shall be possible to perform photometry on linearized images using
single star psf-fitting techniques.
.le
.ls (3)
It shall be possible to subtract the fitted psf from the data.
.le
.ls (4)
All photometry routines shall be usable either interactively or in a
batch mode, to process an arbitrarily long list of objects on a single image.
.le
.ls (5)
All photometry routines shall produce accurate estimates of the uncertainties
in object centers and magnitudes.
.le
.ls (6)
A routine shall be provided to automatically locate all objects in an image
which are sufficiently bright and well resolved (unblended) to be measured
by aperture or single star fitting techniques.
.le
.ls (7)
Routines shall be provided to determine the PSF of an image by either
empirical or analytical techniques.  It shall be possible to accurately
determine the PSF even if the data is undersampled (up to the limit defined
by the sampling theorem).
.le
.ls (8)
Given a set of images, each of which has a different PSF, it shall be
possible to compute and apply a transformation to each image which
will result in all output images having the same PSF.
.le
.le

.ks
.nf
Subpackages:

    apphot		aperture photometry
    new_richfld		single star psf-fitting techniques
    nstar		deconvolution of blended images
    psf			psf generation and modification
.fi
.ke

The requirements and specifications of the APPHOT package have already
been written and are available as a separate document.  The "new richfld"
package will be similar in operation to APPHOT, but centering and scaling
will be done by psf-fitting techniques, providing more precise centers
and magnitudes, the ability to work in slightly more crowded fields
than is possible with APPHOT, and the ability to fit partial images.
The new richfld program will be a considerable improvement over the existing
IPPS version, providing a better background fitting algorithm, greater
efficiency, better error estimates, an improved user interface, and
probably the ability to perform accurate photometry on undersampled data.

The NSTAR problem is still a research project, and it is unlikely that
we will have the manpower to address this problem for quite some time yet.

.sh
3.6 Package DTOI

    A collection of routines for computing and applying the density to
intensity transformation for photographic data, and for linearizing other
types of data as well.  The requirements are as follows:
.ls
.ls (1)
It shall be possible to determine the H-D curve for photographic data,
by any of the following techniques:
.ls o
By fitting a set of data points (the calibration "spots"), each of which
is described by a modal value and a standard deviation or weight,
and where the upper bound on the number of data points is arbitrary.
The data points shall be input in the form of a list file or list structured
parameter.
.le
.ls o
By analysis of a single image containing many star images.  Since stellar
images must scale linearly if the data is linear, the H-D curve of an
image can be derived from an analysis of the data itself.
.le
.ls o
By use of an external program, or by direct entry of the transformation
by the user.
.le
.le
.ls (2)
A convenient routine shall be provided for generating the spot list file
from the calibration spots in digital form.
.le
.ls (3)
It shall be possible to determine the departure from linearity of
digital detectors by analysis of a set of images of the same field,
where successive images differ only in the total exposure time.
Each image is in effect a calibration "spot".
.le
.ls (4)
A function shall be provided to apply the transformation, linearizing an image
or images.
.le
.ls (5)
A function shall be provided to apply the reverse transformation, producing a
nonlinear image or images for test purposes.
.le
.le

.sh
3.7 Package FILTERPHOT

    A package of routines to reduce data from single or multichannel
photometers.  The function of the package is to read raw data from
a photometer, average multiple observations of an object to produce
a single record, then determine and apply extinction and transformation
corrections.
.ls
.ls (1)
Functions shall be provided to read data from all optical photometry
acquisition programs currently in use at KPNO (#4-16, PPIII, Photom).
.le
.ls (2)
The internal data format shall be independent of the raw data
format, making it straightforward to add additional data format
conversion routines to read data produced by non-KPNO instruments.
.le
.ls (3)
Once data has been read and converted into the internal form,
the primary functions of the package shall be to:
.ls o
Average multiple observations of a single object, producing a single
sky subtracted record.
.le
.ls o
Compute the instrumental magnitudes or colors.
.le
.ls o
Compute and the first and second order extinction coefficients.
.le
.ls o
Compute the transformation coefficients.
.le
.ls o
Apply the extinction corrections, transforming instrumental magnitudes
or colors into natural system magnitudes or colors.
.le
.ls o
Apply the transformation corrections, transforming natural system
magnitudes or colors into standard system magnitudes or colors.
.le
.le
.ls (4)
The package shall be able to reduce data for the BVRI, HBETA, UBV,
UBVR, UBVRI, UVBY, and UVBYHBETA photometric systems.
.le
.ls (5)
It shall be straightforward to extend the package to reduce data in
other photometric systems, provided they are reasonably similar to the
standard systems.
.le
.le

.sh
3.8 Package FOCAS

    A more or less direct conversion of the existing FOCAS package to
IRAF, excluding those routines which duplicate functions already provided
by the IRAF system, such as data i/o, image reductions, image display load
and control, etc.  The package shall provide the following functions:
.ls
.ls (1)
Automatic detection of faint objects, producing a catalog of objects
as output.
.le
.ls (2)
Measurement of various position, shape, and photometric parameters for
each object.
.le
.ls (3)
Automatic classification of objects (i.e., as stars or galaxies),
based on the information determined in steps (1) and (2).
.le
.ls (4)
Display and analysis of the various parameters in the catalogs.
.le
.le

.sh
3.9 The HELP Utility

    The HELP utility shall be used to retrieve and display documentation
on-line, i.e., while at the terminal using the system.  Documentation shall
be organized by package; "manual pages" shall be available for both CL and
library level packages.  A manual page shall be available on-line for each
item appearing in a CL menu.
.ls
.ls (1)
The command "help" with no arguments shall cause a one line description of
each routine in the current package to be printed.
.le
.ls (2)
A command of the form "help task" shall cause the manual page for the
named task to be printed.  The task must be defined in the dictionary at
the time HELP is executed to be recognized.
.le
.ls (3)
A command of the form "help package.task" shall retrieve the manual page
for the named task regardless of whether the associated package is loaded.
This form must be used to get help on library procedures.
.le
.ls (4)
It shall be possible, as an option, to print only the calling sequence for
the task, to print only detailed information for a particular parameter,
or to print the source for the task.
.le
.le
.le

.sh
3.10 Package IMAGES

    General image processing.  Included are routines for displaying and
plotting images and image sections, for image arithmetic, editing, and
filtering, and for performing geometric and other transformations.
.ls
.ls (1)
A routine shall be provided for mapping an image or image section into
the user specified frame of the default image display device.  The mapping
or display routine shall have the following features:
.ls (a)
The function of the display routine shall be to map an image or image section
into the specified frame of the default image display device.
The following simple calling sequence shall suffice to display an image
or image section:

	display (image, frame)

where "image" is the name of an image or image section, and "frame" is
the frame to be used, numbered 1, 2, 3, etc.  For example, if "cube"
is a three dimensional image cube, the command

	display ("cube[*,-*,5]", 1)

would map the entire fifth band of the cube into frame number 1, with the
y-axis flipped (the IMIO interface transparently processes image sections).
Default transformations would be used to map image coordinates into
display coordinates, and image pixel values into display pixel values.
.le
.ls (b)
The following options shall be available, under control of hidden
parameters with default values:
.ls o
Erase frame before displaying image.
.le
.ls o
Scale the x,y dimensions of the image to fit the physical frame of the
display device (autoscale in x,y).  The aspect ratio should be maintained
at unity, unless an option is added to permit independent scaling of
the two axes.
.le
.ls o
Do not autoscale in x,y, i.e., map the image 1 to 1 in x,y (into center
of window).
.le
.ls o
Enter explicit x,y scaling factors (magnification).  Map image into
center of frame using these fixed scaling ratios.
.le
.ls o
Enter Z1 and Z2, the range of intensities to be mapped into the
8 bits (or whatever) available on the physical device.
.le
.ls o
Reuse the spatial and greyscale transformations used the last time
the display routine was called.
.le
.ls o
Autoscale, using the minimum and maximum pixel values.
.le
.ls o
Autoscale, by computing a full or partial histogram for the image,
and then automatically computing the values of Z1 and Z2 which straddle
the main peak of the histogram (if there is a single peak).
It may be desirable to subsample the image for the sake of efficiency.
.le
.ls o
Both logarithmic and linear grayscale transformations shall be
available.
.le
.le
.ls (c)
Though the implementation of the display routine will necessarily be
device dependent at some level, the functions provided by the routine
shall be reasonably device independent.
.le
.ls (d)
The default image display device shall be specified in the
CL environment table (normally set when the CL starts up).
.le
.le

.ls (2)
A routine shall be provided to control and adjust the image display
device.  The following functions shall be provided:
.ls
.ls o
Select frame to be displayed.
.le
.ls o
Erase graphics frame.
.le
.ls o
Erase image frame.
.le
.ls o
Adjust windowing (frame lookup table).
.le
.ls o
Zoom and roam.
.le
.ls o
Blink frames.
.le
.le

The display control routine will provide rudimentary control of the image
display device, but will not exercise any of the advanced features commonly
found on sophisticated modern display devices.  This routine will eventually
be supplanted by a control program driven by a dedicated terminal with a
touch screen overlay.  The latter interface will exercise the advanced
features of the display, but will necessarily be more device dependent
and therefore less transportable.

In the long run we will wish to keep both interfaces, using the simple
interface for simple display devices, for workstations which do not have
a dedicated display control terminal, and to provide rudimentary control
at installations which cannot afford to implement the more sophisticated
interface.
.le

.ls (3)
Routines shall be provided for plotting image data in a variety of ways,
on a variety of devices.
.ls (a)
The following types of plots shall be provided:
.ls o
Vector plots along a single dimension, optionally performing a boxcar
average over the other image dimensions.
.le
.ls o
Vector plots of the histogram of an image or image section.
.le
.ls o
Mark, vector, and text drawing on an existing plot, where the position,
size, orientation, etc., of a mark or text string are specified by the user.
.le
.ls o
Two dimensional contour plots of an image or image section.
.le
.ls o
Two dimensional hidden line plots of an image or image section.
.le
.ls o
Three dimensional hidden line plots of an image or image section.
.le
.ls o
Grayscale or simulated grayscale plots of a two dimensional image or
image section (depending on the output device).
.le
.le
.ls (b)
The following types of graphics output devices shall be supported:
.ls o
Graphics terminals (e.g., VT100, Tek 4012).
.le
.ls o
Raster plotters (e.g., Versatec).
.le
.ls o
Pen plotters (e.g., Calcomp, Imagen).
.le
.ls o
Grayscale devices (e.g., Dicomed, IIS).
.le
.ls o
Files (for spooling graphics).
.le
.le
.ls (c)
The following options shall be available to control the form of
a vector plot:
.ls o
Overplot without changing the scale.
.le
.ls o
Plot to a user specified scale.
.le
.ls o
Plot vector points as dots.
.le
.ls o
Plot vector points as marks, where the type and size of a mark
is specified by the user.
.le
.ls o
Connect the points of a plotted vector with line segments.
.le
.ls o
Connect the points of a plotted vector with dashed line segments,
where the dash pattern is specified by the user.
.le
.ls o
Set the plotting window, i.e., the position and size of the rectangle
in which the plot will be drawn on the output device.
.le
.ls o
Specify whether or not data may be plotted outside of the plotting window.
.le
.ls o
Enter labels for the axes.
.le
.ls o
Specify whether or not a box with ticks is to be drawn to define the
plotting window.
.le
.ls o
Specify whether the axes are to be labeled in pixel or user coordinates
(user coordinates might be right ascension and declination, wavelength
versus flux, or whatever).
.le
.ls o
Select linear or log scaling in either axis (with appropriately labeled
ticks).
.le
.ls o
Other options, such as line color, line brightness or width, depending
on the characteristics of the final graphics interface (GIO).
.le
.le
.ls (d)
Due to the complexity of the vector plotting options, the vector plot
task shall be command driven.  A simple language shall be defined for
specifying vector plots and for drawing mark and text strings, and a
plot shall be generated by entering a sequence of commands which are
interpreted by the plotting task.

All plotting options shall have default values.  These default values
may be set by having the plot task read a user specified initialization
file (containing normal plot commands) upon startup.  The simplest
plot command will have the form

	plot image_section

i.e., the command

	plot "cube[5,*,9]"

would plot column 5 of band 9 of the image "cube".  If only a single
command is needed to generate a plot, it shall be possible to pass the
command as a string argument to the vector plot task when the task is
invoked from the CL.  Otherwise, commands shall be read from the
standard input.
.le
.ls (e)
The two tasks PLINE and PCOLUMN shall be provided for making simple line and
column plots of images, without the extra overhead associated with the
vector plot task.  Thus, a command such as

	pline image,10

would suffice to plot line 10 of the image "image".
.le
.ls (f)
It shall be possible to specify the default graphics device in the
CL environment table (normally set when the CL starts up).
.le
.ls (g)
It shall be possible to redirect the plot to a device other than the
default graphics device by means of command line redirection.
.le
.ls (h)
It shall be possible to select an output "device" which spools the low
level plotting instructions in a disk file.
.le
.le

.ls (4)
Simple pointwise image operations, i.e. picture arithmetic, functions,
line and column flipping, subraster extraction, and so on, shall be
performed by the image calculator task.  The image calculator approach
has two major advantages: (1) a great deal of function is provided
via an interface which is simple and easy to remember, and (2) the
image calculator is efficient, since it eliminates may intermediate
images which would otherwise have to be written, read, and deleted.
For all but the most trivial expressions the image calculator will be 
cpu bound, an ideal candidate for optimization with a bit-mapped array
processor.
.ls (a)
The image calculator task shall be command driven.  If only a single
command is to be executed, it shall be possible to pass the
command as a string argument to the image calculator task when the task is
invoked from the CL.  Otherwise, commands shall be read from the
standard input.
.le
.ls (b)
The function of the image calculator task shall be to execute commands
of the form

	output_image = expression

where "output_image" is either a new image which will be created by the
image calculator or a section of an existing image, and where "expression"
is an algebraic expression wherein the operands may be any of the following:
.ls
.ls o
Images or image sections of any dimension or datatype.
.le
.ls o
Numeric constants.
.le
.ls o
Calls to intrinsic functions.
.le
.le

For example, the command

    cl> imcalc "subras = image[40:50,33:43]"

would extract a subraster from the image "image" into the new image
"subras".  The command

    cl> imcalc "image = image[*,-*]"

would flip the columns of the two-dimensional input image.  The command

    cl> imcalc "avg = (a + max(b,0) + c) / 3"

where "a", "b", and "c" are the names of images,
would produce the new image "avg" which is the average of the images
"a", "c", and the image "b" with all negative pixels set to zero.
Finally,

.nf
    cl> imcalc "image[50,*] = (image[49,*] + image[51,*]) / 2"
.fi

would replace column 50 of the named image by interpolation over the
neighboring columns.  Many other examples could be given,
but this should suffice to demonstrate the range of operations the
image calculator will be able to perform.
Common operations, or repetitive operations on large data sets,
can be performed by writing CL scripts to generate sequences of commands
to drive the image calculator.
.le
.ls (c)
The operation of the image calculator when evaluating "mixed mode"
expressions involving images which differ in size, number of dimensions,
datatype, or which involve out of bounds references, has not yet been
fully defined.
.le
.ls (d)
The function of the image calculator shall be limited to pointwise
image operations (no interpolation, filtering, etc.).
.le
.ls (e)
The syntax of an expression in the image calculator shall be the same
as for the SPP language (and Fortran 77).
The image calculator shall recognize the following operators:

.ks
.nf
    +			addition
    -			subtraction
    *			multiplication
    /			division
    **			exponentiation
    -			unary negation
    < <= > >= == !=	boolean comparison
    !			boolean negation
.fi
.ke
.le

The result of a boolean expression shall be of type short integer, 
where zero corresponds to false and one to true.  Boolean expressions
are useful for thresholding and mask generation.

.ls (f)
The image calculator shall implement the following intrinsic functions:

.ks
.nf
    abs      atan2    cos      int      min      sin       
    acos     ceil     cosh     log      mod      sinh      
    aimag    char     double   log10    nint     sqrt      
    asin     complex  exp      long     real     tan       
    atan     conjug   floor    max      short    tanh      
.fi
.ke
.le
.ls (g)
The image calculator shall merge the bad pixel lists of the input images
to produce the bad pixel list of the output image.
.le
.ls (h)
A set of CL callable subroutine-like tasks shall also be provided for
performing simple arithmetic operations on images (two images in, one out),
without incurring the overhead associated with the image calculator.
.le
.ls (i)
A specialized routine shall be provided for averaging a set of registered
images.
.le
.le

.ls (5)
General pointwise operations are required to modify the intensity scale
of an image in ways that are difficult or impossible to perform with the
image calculator.  The following operators are required:
.ls
.ls o
General pointwise mapping operator.  The mapping of input intensity to
output intensity shall be defined by a user supplied transformation curve.
The transformation curve shall consist of a list of data points giving
output intensity versus input intensity.
.le
.ls o
Histogram equalization operator.
.le
.ls o
Histogram matching operator.
.le
.le
.le

.ls (6)
Operators are required to perform various geometric transformations.
These transformations move pixels about, but do not change the values
of the pixels.  The geometric transformations shall be implemented as
separate tasks.
.ls (a)
Operators shall be provided for the following transformations:
.ls o
Transpose.  Note that 90 degree clockwise and counterclockwise
rotations may be effected by combining the transpose operator
with an image section subscript as follows:

.ks
.nf
    transpose ("in[*,-*]", out)		(cw rotation)
    transpose ("in[-*,*]", out)		(ccw rotation)
.fi
.ke
.le
.ls o
Fractional pixel shift along any dimension or dimensions.
.le
.ls o
Expand or contract by any factor along any dimension or dimensions.
.le
.ls o
Expansion by pixel replication.
.le
.ls o
Contraction by block averaging.
.le
.ls o
General linear transformation; a fraction pixel shift followed by a
rotation though an arbitrary angle about an arbitrary center.
.le
.ls o
General geometric distortion, or "rubber sheet", where the transformation
is defined by means of an externally generated lookup table.
The transformation shall be described by giving the coordinates of a set
of grid points in the input image, and the corresponding coordinates of
the same grid points in the output image.  The distortion routine shall
compute the mapping for non-grid points by interpolation.
Note that this operator may be used to implement rotations or translations,
to register images, to remove or induce geometric distortions,
to convert from Cartesian to polar representation and vice versa, and so on.
.le
.ls o
Distortion table generation.  Given the coordinates of a set of grid points in
the input image, and the corresponding coordinates of the same grid
points in the output image, an analytic surface is fitted, and a new set
of grid points are generated by sampling the analytic surface.
This step is necessary when too few grid points are available to span
the image, or when a smooth or constrained transformation is desired.
Note that this operator is very similar to that used for astrometry.
.le
.ls o
Image registration: given a list of images, compute the unique transformation
required to register the images with minimum loss of data.
The linear transformation routine may subsequently be used to perform the
actual registration.  Operation shall be restricted to linear transformations
(translation and/or rotation).  It shall be possible to restrict the
transformation to a simple translation if desired.
.le
.le
.ls (b)
All operations which involve interpolation shall offer the following
choice of interpolators:
.ls o
Nearest neighbor.
.le
.ls o
Linear interpolation.
.le
.ls o
Third order interior polynomial.
.le
.ls o
Fifth order interior polynomial.
.le
.ls o
Cubic spline.
.le
.ls o
Sinc function.
.le
.le
.ls (c)
All operations which involve out of bounds references (i.e., a rotation
or a geometric distortion) shall offer the following options for out of
bounds references:
.ls o
Add the pixel to the bad pixel list.
.le
.ls o
Return the value of the nearest boundary pixel.
.le
.ls o
Return a constant value.
.le
.ls o
Generate value by reflection about the boundary. 
.le
.ls o
Generate value by projection about the boundary. 
.le
.ls o
Generate value by wrapping around to the opposite side of the image.
.le
.ls o
Apodize (for fourier analysis).
.le
.le
.ls (d)
Operations which change the spatial scale of the data (i.e., expand, contract,
or distort) shall by default scale the value of the output pixels so as
to conserve the volume integral.
.le
.ls (e)
All linear transformation operators shall also transform the axes descriptor
in the image header, so that the user coordinate system associated with
the image remains accurate.
.le
.le

.ls (7)
Operators are required to perform various filtering operations on images.
These transformations change the values of the pixels, but do not move
pixels about or change the spatial scale of the image.  The filtering
operators shall be implemented as separate tasks.
.ls (a)
The following filter operators are required:
.ls o
Gradient (first derivative).
.le
.ls o
Laplacian (second derivative).
.le
.ls o
Circular median filter.
.le
.ls o
Rectangular median filter.  May be used for median filtering of lines
and columns.
.le
.ls o
Circular modal filter.
.le
.ls o
Rectangular modal filter.
.le
.ls o
Convolution via a gaussian kernel of arbitrary size.
.le
.ls o
Convolution via a flat topped rectangular kernel of arbitrary size
(boxcar smoothing).
.le
.ls o
Convolution via a user specified kernel of arbitrary size.
.le
.ls o
Lucy smoothing using boxcar smoothing or a user supplied convolution
kernel.
.le
.ls o
General lowpass filter operator.
.le
.ls o
General highpass filter operator.
.le
.ls o
General bandpass filter operator.
.le
.ls o
General bandstop filter operator.
.le
.ls o
A routine which converts a transfer function in the frequency domain into the
corresponding convolution kernel in the spatial domain.
.le
.ls o
Forward fourier transform.
.le
.ls o
Inverse fourier transform.
.le
.ls o
Power spectrum.
.le
.le
.ls (b)
The choices for dealing with out of bounds pixel references shall be
the same as given in section 6(c).
.le
.le
.ls (8)
Special operators are required for background or bias fitting and removal.
The following fitting operators are required:
.ls (a)
Line polynomial fit to a user defined set of regions.  This operator shall
perform the following operations for each line in the image:
.ls o
Compute the median, mode, or mean of each region in the line,
optionally with automatic pixel rejection and region growing.
.le
.ls o
Fit a polynomial to the resulting set of points, where the order of the
polynomial is greater than or equal to zero and is specified by the user.
.le
.ls o
Evaluate the fitted polynomial to produce the output line.
.le
.le
.ls (b)
Surface polynomial fit to a user defined set of regions in a two
dimensional image.  As above, but regions are defined along the columns
as well.
.ls o
Compute the median, mode, or mean of each subraster,
optionally with automatic pixel rejection and region growing.
.le
.ls o
Fit a two dimensional polynomial to the resulting set of points,
where the order of the polynomial in each dimension is greater than
or equal to zero and is specified by the user.
.le
.ls o
Evaluate the fitted surface to produce the output image.
.le
.le
.ls (c)
One or two dimensional surface fit to the pixel data directly,
without computation of the mode, median, or whatever.
A number of regions may be defined as in the other routines,
or the entire raster may be fit.  A two dimensional Legendre polynomial
is fitted, pixel rejection with region growing is performed if enabled,
and the process iterates until convergence (two or three passes through
the image are required).  The fitted surface is evaluated to produce
the output image.
.le
.le

.ls (9)
A range of operators are required for editing rasters.  Raster editing
may be used to remove artifacts or blemishes, to salvage calibration frames
containing contaminating objects, to implement nonlinear filtering in the
fourier domain, and so on.  The image calculator provides a rudimentary
but powerful raster editing capability, allowing lines, columns, subrasters,
and pixels to be copied or directly modified.  The filtering operators may
also be used for a certain class of editing operations.  Additional special
purpose operators are required for detecting and removing extended artifacts.
.ls (a)
The following operators are required:
.ls o
An operator is required to automatically detect and remove spikes.
Pixels which exceed the median of a circular or rectangular region by
more than a certain amount, and optionally all neighboring pixels out
to a given radius, shall be replaced by artificial values.
.le
.ls o
An operator is required to automatically detect and remove extended
objects.  Region growing should be available as an option to insure
that all contaminated pixels are replaced.
.le
.ls o
An operator is required to automatically detect and remove transient defects,
given a series of exposures of the same field taken at different times.
.le
.ls o
An interactive editing routine is required, wherein the user interactively
marks the region to be edited with a cursor.
.le
.le
.ls (b)
It shall be possible to replace pixels by any of the following
techniques:
.ls o
By the median of the neighboring pixels, out to a user specified
radius, with optional additive noise.
.le
.ls o
By interpolation (linear or spline), with optional additive noise.
.le
.ls o
By adding the pixels to the bad pixel list for the image.
.le
.ls o
By substituting a user defined value, with optional additive noise.
.le
.le
.le

.sh
3.11 Package IMRED

    The Image Reductions package (IMRED) will provide streamlined or
"canned" procedures for reducing the data from specific KPNO digital
imaging detectors.  As far as possible, the IMRED procedures shall be
written as CL scripts calling compiled procedures in other packages.
Most of the functionality needed to reduce direct and spectroscopic
imaging data will be provided by the general purpose routines in the
IMAGES package.

The advantages of writing IMRED procedures as CL scripts are the following:
(1) the high level IMAGES tasks, such as the image calculator, can be used
directly instead of calling lower level library procedures, 
(2) staff and users can modify CL scripts more easily than compiled
procedures, and (3) we can provide specialized routines for common reduction
tasks, without sacrificing generality.  The principal disadvantage is that
it is harder to access data dependent fields in the image header,
such as the filter number or IPS parameter for Video Camera images.

Canned procedures shall be provided to reduce data from the following
KPNO instruments:
.ls
.ls (1)
CCD direct.  Bias determination is via the polynomial fitting routines
in the IMAGES package; trim, bias subtraction and flat field division is
via the image calculator, cleaning is via the image editing routines,
and so on.  A special routine will probably be required for defringing.
.le
.ls (2)
Echelle CCD.  Reductions are much the same as for the CCD direct.
A different defringing algorithm is required.  Cleaning and order
extraction is via the MULTISPEC procedures.
.le
.ls (3)
HGVS (High Gain Video Spectrometer).  The basic operations are the
same as for the CCD's.  An additional call to a polynomial fitting routine
is required to compute the slit profile.  Distortion mapping is via the
LONGSLIT procedures.
.le
.ls (4)
Cryogenic Camera.  Reductions are the same as for the HGVS,
except than an additional rotation or transposition step is required.
.le
.ls (5)
Video Camera.  Reductions are very similar to those for the CCD direct,
except that there is no defringing problem.  The reduction procedures should
be able to make use of the filter number and IPS parameter for each frame.
Distortion mapping need be done only once for a given image tube,
and hence is not part of the normal reduction sequence.
Distortion removal is via the geometric distortion routine in IMAGES.
.le
.ls (6)
Coude CCD.  Standard CCD reductions, followed by compression to one
dimensional spectra for subsequent analysis in ONEDSPEC.
.le
.le

Although canned procedures will not be provided (at least initially) for
reducing data from non-KPNO digital detectors, it should not be difficult
for users to modify the standard scripts to reduce data from other
detectors.

.sh
3.12 Package LANGUAGE

    The command language itself.  Not a normal package, in that the tasks
are built into the CL process, rather than into separate processes.
The contents of this package are always "loaded".  The purpose of the
LANGUAGE package is to summarize the language facilities, and to prompt
the user with the names of the language "tasks", so that HELP may be
called to obtain additional information.

.sh
3.13 Package LISTS

    Routines for operating upon lists.  A list is a text file wherein
each line is a record consisting of one or more columns.  Lists may be
produced by output redirection, editing, and many other means.  Examples
of lists are lists of object coordinates, lists of images, lists of
regions, lists of transformation points, the graphics and image cursors,
and so on.  Lists are used throughout the system.
.ls
.ls (1)
For maximum flexibility, all list operators shall be implemented as filters.
.le
.ls (2)
Operators shall be provided to perform the following functions:
.ls o
Copy selected columns from the input list to the output list.
.le
.ls o
Concatenate lines from a list of input files (merge records from several
lists).
.le
.ls o
Sort a list, alphabetically or numerically, in increasing or decreasing
order, by the contents of any column.
.le
.ls o
Merge several sorted lists, alphabetically or numerically,
in increasing or decreasing order, by the contents of any column.
.le
.ls o
Filter a list, passing or stopping only those lines which are within
the specified numeric or alphabetic range.
.le
.ls o
Filter a coordinate list, passing or stopping only those coordinates
which are within a certain radius of a certain origin.
.le
.ls o
Filter a list, passing or stopping only those lines which contain a
substring matching a user defined pattern.
.le
.ls o
Break the input list up into a stream of words.
.le
.ls o
Organize a stream of words into a neatly formatted table.
.le
.ls o
Copy the special list GCUR (the graphics cursor) to the output list.
.le
.ls o
Copy the special list IMCUR (the image cursor) to the output list.
.le
.ls o
Graph the contents of one or more lists, producing a plot on the
standard graphics device.  If more than one list is input, the individual
curves (lists) shall be overplotted.
.le
.ls o
Perform arithmetic upon the columns of lists (e.g., OPSTRM).  The output
columns are functions of the input columns.
.le
.ls o
Average a list of numbers, each of which may have an associated weight.
.le
.ls o
Average a list of coordinates, each of which may have an associated weight.
.le
.ls o
Convert a list to upper case.
.le
.ls o
Convert a list to lower case.
.le
.ls o
Perform a user specified mapping of the characters within a list.
.le
.ls o
Count the number of lines, words, and characters in a list or in a
list of files.
.le
.le
.ls (3)
When appropriate, the list operators should be set up to operate either
upon a list of input files, or upon the standard input.
.le
.le
.le

.sh
3.14 Package ONEDSPEC

    The one dimensional spectral reduction and analysis package.
A general purpose package or packages, with a separate set of higher level
"canned" procedures for reducing data from specific KPNO instruments.
The basic requirements are as follows:
.ls
.ls (1)
Spectra shall be stored as one dimensional images with an extended header
containing special fields used by ONEDSPEC.  This will permit use of the
standard image calculator and graphics utilities to manipulate and plot
spectra.
.le
.ls (2)
An assortment of routines are needed for data input.  Routines are required
to convert data from the following formats into ONEDSPEC images:
.ls o
FITS.  The standard FITS reader should be sufficient, provided it can
handle mapping of nonstandard keywords into the application specific
part of the image header.
.le
.ls o
IIDS, IRS.
.le
.ls o
REDUCER.
.le
.ls o
Text files.  The standard DATAIO card image reader will suffice to convert
card image files into text files, but a special routine will be needed
to convert a text file spectrum (format yet to be defined) into an image.
.le
.le
.ls (3)
Only the standard FITS and text file (hence card image) formats will be
supported for output of spectra.
.le
.ls (4)
The image calculator shall be used for arithmetic and other operations upon
spectra, unless special handling of the extra fields in the image header
is required.
.le
.ls (5)
The standard IMAGES graphics utilities shall be used for plotting spectra,
except within interactive analysis procedures.  The user coordinate systems
in the image header (x, y, and flux) must be initialized by ONEDSPEC if user
coordinates are desired on graphics output.  The standard graphics utilities
(the image header) support only linear coordinate transformations.  
.le
.ls (6)
A routine shall be provided for editing the special fields of the ONEDSPEC
image header.
.le
.ls (7)
Operators shall be provided for the following standard reduction 
operations:
.ls o
Line identification.
.le
.ls o
Dispersion solution.
.le
.ls o
Dispersion correction.  The data is interpolated and rewritten to
a user defined dispersion scale (linear, log lambda, etc., in units of
angstroms, wave number, inverse cm., etc.).
.le
.ls o
Flux calibration.
.le
.ls o
Coincidence correction.
.le
.ls o
Atmospheric extinction correction.
.le
.ls o
Merging of spectra (i.e., Echelle orders), to form a single
spectrum.
.le
.le
.ls (8)
Analysis functions shall include at least the following:
.ls o
Velocity measurement of individual lines.
.le
.ls o
Velocity measurement by cross-correlation.
.le
.ls o
Continuum estimator.
.le
.ls o
Intensity measurement.  Equivalent width via aperture integration,
profile fitting, pseudo-filter.
.le
.ls o
Analytical and empirical generation of line profiles.  Modeling of
line profiles.
.le
.ls o
Deconvolution of blended lines.
.le
.ls o
Fourier transforms, power spectrum, filtering, etc., mostly via the standard
routines in the IMAGES package.
.le
.le
.ls (9)
The package shall be able to handle spectra up to several million
pixels in length.
.le
.ls -5 (10)
Canned reduction procedures shall be provided for the following
KPNO instruments:
.ls o
IIDS, IRS
.le
.ls o
McMath FTS
.le
.ls o
4-Meter FTS
.le
.le

The ONEDSPEC package will be one of the most heavily used packages in
the system, and should be sufficiently general to handle the reduction
and analysis of one dimensional spectra from a variety of instruments.
.le

.sh
3.15 Package SOFTOOLS

    Software tools.  A collection of tools used to develop and maintain
software systems.
.ls
.ls (1)
The following tools shall be provided:
.ls o
A compiler for the SPP language.
.le
.ls o
A portable, general purpose editor (probably the "tools" editor,
converted as required for IRAF).
.le
.ls o
Tools for making, updating, and accessing archives.
.le
.ls o
A simplified IRAF version of the MAKE utility (required to automatically
generate packages on non-UNIX systems).
.le
.ls o
The SYSGEN utility, used to maintain the IRAF system.
.le
.ls o
A utility which lists the names of all procedures and commons
defined in a set of SPP source files on the standard output.
.le
.ls o
A utility which compares a list of external identifiers with those used
in the IRAF libraries, and passes the names of only those identifiers which
redefine library routines (if any).
.le
.ls o
A utility which produces a cross reference list for the SPP source
files in a package.
.le
.le
.ls (2)
All tools shall be written in the SPP language as standard CL callable
IRAF tasks, and shall be as transportable as possible.
.le
.le

.sh
3.16 Package NSURFBRT (to be renamed)

    Digital surface brightness analysis of extended objects, such as
galaxies.
.ls
.ls (1)
The main function of the package shall be to fit ellipses to the isophotes
of extended objects (galaxies), without artificially constraining the 
center, position angle, or ellipticity of the fitted curves.
.le
.ls (2)
Output shall consist of a set of isophotes, defining the shape, orientation,
magnitude, and position of the object as a function of major and minor
axis radius.
.le
.ls (3)
The fitting routine shall optionally be able to detect contaminating
objects such as stars, and exclude them from the fit.
.le
.ls (4)
All analysis routines shall be usable either interactively or in batch
mode, processing an indefinitely large list of objects.
.le
.ls (5)
All analysis procedures shall exclude bad pixels from the fit.
.le
.ls (6)
Accurate estimates of the uncertainties of all calculated parameters
shall be computed.
.le
.ls (7)
Graphics utilities shall be provided for producing contour like plots
of the fitted isophotes, for plotting radial profiles, ellipticity
gradients, migration of the major axis, and so on.
.le
.ls (8)
Output from the main analysis routine shall be in the form of a
table printed on the standard output, permitting use of the standard
list processing utilities for general analysis, and of the card image
utilities for data export.
.le
.le
    
.sh
3.17 Package SYSTEM

    The SYSTEM package shall provide general purpose routines for file
manipulation and status, directory listing, device allocation and
deallocation, time and date, and so on.
.ls 
.ls (1)
The following functions shall be provided:
.ls o
Allocate a device (i.e., magtape).
.le
.ls o
Deallocate a previously allocated device.
.le
.ls o
Print status information for an allocatable device.
.le
.ls o
Clear the terminal screen.
.le
.ls o
Beep the terminal (useful for wakeup after a long command or command
sequence).
.le
.ls o
Concatenate a list of files.
.le
.ls o
Copy a file, copy a list of files to a directory.
.le
.ls o
Delete a file or files.
.le
.ls o
List the names of the files in the current directory, in one or more named
directories, or just give information about one or more named files.
A short form shall be provided, wherein only the name of the file is given.
A long form shall also be provided, giving the name, access and delete
permissions, file type (text or binary), file size, date of last modify,
and so on for each file in the list.
.le
.ls o
Summarize the amount of disk space currently available.
.le
.ls o
Echo command line arguments on the standard output (which can be redirected
to do useful things).
.le
.ls o
Print the first few lines of a file or files.
.le
.ls o
Print the last few lines of a file or files.
.le
.ls o
Page through a file or files, pausing at the end of each screen of text.
.le
.ls o
Print a file or files on the standard line printer device.
.le
.ls o
Protect a file or files from deletion, accidental or otherwise.
.le
.ls o
Remove protection from a file or files.
.le
.ls o
Rename a file, or move a list of files to a different directory.
.le
.ls o
Print information on who is using the system, what they are doing,
how much cpu time, etc., they have used, and so on.
.le
.ls o
Tee the standard output.
.le
.ls o
Print the time and date on the standard output.
.le
.ls o
Type the contents of a text file or files on the standard output.
.le
.ls o
Change the current directory.
.le
.le
.ls (2)
Some of these routines will necessarily be machine dependent.
.le
.ls (3)
Whenever possible, a routine will be set up to operate either on a list
of files specified by pattern matching, or to read from the standard
input if so directed on the command line.
.le
.ls (4)
All routines which operate on files shall accept either virtual file
names, which are machine independent, or operating system dependent
pathnames.
.le
.ls (5)
It shall be possible, at the discretion of the user, for a newly created
file to silently clobber an existing file of the same name; otherwise,
the system will refuse to clobber an existing file (the routine will
abort and an explicit delete will be required).
.le
.le

.sh
3.18 Package TWODSPEC

    Two dimensional spectral reduction and analysis.  A set of general purpose
packages, with separate canned procedures for reducing the data from standard
KPNO two dimensional spectrographic instruments.  Two main subpackages
shall be provided: (1) MULTISPEC, which fits and extracts one dimensional
spectra from two dimensional images, and (2) LONGSLIT, which reduces
true two dimensional spectra (the names of these packages may change).
.ls
.ls (1)
The main function of the MULTISPEC package shall be to extract flattened
one dimensional spectra from two dimensional images.  The following
functions shall be provided:
.ls o
Production of flat field frames by fitting quartz calibration images.
.le
.ls o
Flat field correction of multispectral data.
.le
.ls o
Cleaning of the spectra.
.le
.ls o
Extraction of the individual object spectra for further processing in
ONEDSPEC.
.le
.le
.ls (2)
It shall be possible to extract blended spectra via deconvolution
techniques.
.le
.ls (3)
It shall be possible to extract spectra superimposed on a slowly varying
background.
.le
.ls (4)
It shall be possible to accurately fit spectra even though the PSF
varies slowly over the image.
.le
.ls (5)
It shall be possible to reliably and accurately trace spectra
in the presence of geometric distortions (pincushion, s, shear, etc.).
.le
.ls (6)
It shall be possible to compute the residual of the data image minus
the fitted image, to evaluate the quality of the fit.
.le
.ls (7)
The program shall compute accurate estimates of the uncertainties in the
fitted parameters.
.le
.ls (8)
The routines in the MULTISPEC package shall be general purpose, i.e.,
not tied to the data from any particular instrument.
.le
.ls (9)
Canned procedures which are instrument specific shall be provided for
the reduction of data from the following KPNO instruments:
.ls o
Multiaperture CRYOCAM.
.le
.ls o
Multiaperture HGVS.
.le
.ls o
Echelle.
.le
.le
.le

The LONGSLIT package shall reduce true two dimensional spectrographic
data.  The primary input is a flattened two dimensional spectrum
(wavelength versus arcseconds on the sky), and various spectral and flux
calibration images.  The primary output is a distortion corrected,
sky subtracted one or two dimensional spectrum.  The LONGSLIT package
shall also provide a two dimensional spectral analysis capability.

The LONGSLIT package shall provide the following reduction functions:
.ls
.ls (1)
Geometric distortion mapping.  The basic procedure is as follows:
.ls o
A stellar-like object frame or (fully resolved) multislit frame is traced
to determine the distortion in the cross dispersion direction.
.le
.ls o
A full slit arc frame is traced to determine the distortion along the
direction of the dispersion.
.le
.le
.ls (2)
Line identification.  Given an arc frame to be used to perform the
dispersion solution, identify the individual arc lines, assign wavelengths,
and generate a line list to be used for the dispersion solution.
.le
.ls (3)
Dispersion solution.  It shall be possible to determine the two dimensional
dispersion for the image (wavelength versus x,y) by fitting a full slit
arc frame, or by analysis of selected regions of an arc frame.
.le
.ls (4)
Remove geometric distortions and correct the dispersion.  A transformation
table shall be prepared and used to drive the geometric distortion routine
provided by the IMAGES package.
.le
.ls (5)
It shall be possible to remove only the geometric distortions, or to both
remove geometric distortions and correct the dispersion scale.  The user
shall be able to specify the following parameters for the output dispersion:
.ls o
Starting and ending wavelength.
.le
.ls o
Dimensions of the output spectrum in pixels.
.le
.ls o
Type of output dispersion curve desired (same dispersion, linear,
log lambda, etc.).
.le
.le
.ls (6)
Slit correction.  The slit function is determined by fitting a polynomial
to an arc line or lines, and used to produce a calibration frame.
The slit function is then removed by an arithmetic operation (this can
all be done with standard IMAGES procedures).
.le
.ls (7)
Sky subtraction.  A smooth sky image is prepared and subtracted from the
data (this can all be done with standard IMAGES procedures).
.le
.ls (8)
Flux calibration.  A standard star spectrum is reduced to a one dimensional
spectrum, flux calibrated by ONEDSPEC, and the result is used to calibrate
one or more two dimensional spectra.  This requires the following
operators:
.ls o
Convert a two dimensional spectrum into a one dimensional spectrum in
ONEDSPEC format.
.le
.ls o
Generate a dummy one dimensional ONEDSPEC spectrum which is subsequently
calibrated by ONEDSPEC.
.le
.ls o
Use the calibrated dummy spectrum to flux calibrate one or more two dimensional
spectra.
.le

The two-to-one conversion routine may also be used if one dimensional output
spectra are desired.
.le
.ls (9)
Canned procedures are required to perform the above reductions for the
following KPNO instruments:
.ls o
Multislit (final output is normally one-dimensional dispersion corrected,
sky subtracted spectra).
.le
.ls o
Long slit spectrographs (output is usually true two dimensional,
dispersion and distortion corrected, sky subtracted spectra).
.le
.le
.le

In addition to the LONGSLIT reduction procedures, the following two dimensional
spectral analysis procedures are required:
.ls
.ls (1)
A two dimensional continuum estimator.
.le
.ls (2)
A routine to trace emission or absorption lines, computing line center,
radial velocity, and equivalent width across the dispersion.
.le
.ls (3)
The line tracing procedure shall be able to trace faint lines out into
the sky, and shall be able to deconvolve blended lines.
.le
.ls (4)
A frequency domain cross-correlation routine is required to compute
radial velocity across the dispersion, using all spectral information
within a user specified range of wavelengths.
.le
.le

.sh
3.19 Package UTILITIES

    Miscellaneous utilities.  Includes routines for precession, computing
airmass, making finding charts, and so on.

.sh
3.20 Special Packages

    The discussion has thus far been limited to those IRAF packages which
are expected to be of general interest to astronomers (and others) around
the country and the world, and which should therefore be included in the
general distribution.  In addition, other packages will be developed in
the IRAF which will probably be used only at KPNO.  Example are the HOLES
program and the Vacumn Telescope reductions package; there are probably
other similar packages which I cannot remember at the moment.  I expect that
many special purpose packages will ultimately be developed by the staff
that do not make it into the general distribution.

.sh
4. Correspondence of existing KPNO software to IRAF Packages

    In this section we go through Harvey and Jeannettes memo of July 1, 1983,
and describe how the functionality provided by each existing KPNO program or
system is provided by the IRAF package structure outlined above.

.nf
        Index     Old Program             IRAF Package

		4M PF photography

	I.A.1	PDSLIB			dataio
	I.A.2	DTOI			dtoi
	I.B.1	ASTRO			astrometry
	I.B.2	IPPS			IRAF
	I.B.3	RICHFLD			digiphot
	I.B.4	AUTOPHOT		digiphot
	I.B.5	SURFBRT			nsurfbrt
	I.B.6	GRASP			nsurfbrt
	I.B.7	FOCAS			focas
	I.B.8	MPC			digiphot

		4M PF / 1-0.9 CCD

	II.A.1	DEBIAS,FPS,FGEN,MEDIAN	imred
	II.A.2	CCDPROC			imred
	II.B.*	(analysis)		(all image packages)

		Video Camera

	III.A.1	VIDCAM			imred
	III.A.2	PROCESS			imred
	III.A.4	DIODE,DISTORT		imred
	III.B	(analysis)		(all image packages)

		IIDS/IRS

	IV.A.1	IDS(IPPS)		onedspec
	IV.A.2	REDUCE(varian)		onedspec
	IV.B.1	IDS(analysis)		onedspec
	IV.B.2	TV			onedspec

		RC / White Spectrograph, Long Slit

	V.A.1	PDSLIB			dataio
	V.A.2	RV			twodspec.longslit
	V.B.1	RV			twodspec.longslit
	V.B.2	FOURIER			twodspec.longslit

		ICCD, Long Slit

	VI.A.1	HGVS			imred
	VI.B.1	RV			twodspec.longslit
	VI.B.2	FOURIER			twodspec.longslit

		Cryo Cam, Long Slit

	(same as ICCD)

		Cryo Cam, Multi-Aperture Data

       VIII.A.1	HOLES			twodspec
       VIII.A.2	MAP			twodspec.multispec
       VIII.A.3	TV			onedspec
       VIII.B.1	TV			onedspec

		Echelle, Photographic

	IX.A.1	PDSLIB, DTOI		dataio, dtoi
	IX.A.2	FASTSCAN		twodspec.multispec
	IX.A.3	ECHORD,TRACE		twodspec.multispec
	IX.B.1	ATLAS,WIDTH		(no plans at present)
	IX.B.2	MOOG			(no plans at present)
	IX.B.3	DECOMP			onedspec (perhaps)

		Echelle, CCD

	X.A.1	ECH			imred
	X.B.1	TV			onedspec

		FTS instruments

	XI.A.1	GRAMMY			onedpsec
	XI.A.2	FTSER			onedpsec
	XI.A.3	REDUCER			onedspec
	XI.A.4	ATLAS			(no plans at present)

		IR and Visible Photometers

	XII.A.1	Hbeta, 4COLOR, etc.	filterphot

		Coude, photographic

       XII.A.1	PDSLIB			dataio
       XII.A.2	SPEC1,2,5		onedspec
       XII.A.3	DISP,DISP5		onedspec
       XII.B.1	(analysis)		onedspec

		Coude, CCD
        XIV.A.1	SPECRED			imred
        XIV.A.2	fourier fitting		imred
        XIV.B	(analysis)		onedspec

		McMath Spectrograph

	XV.A.1	REDUCER			onedspec
	XV.A.2	DECOMP			onedspec, maybe
        XIV.B	(analysis)		onedspec
.fi
.endhelp