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.help scoords May97 onedspec
.ih
NAME
scoords -- set spectrum coordinates from a pixel array (1D only)
.ih
USAGE
scoords images coords
.ih
PARAMETERS
.ls images
List of one dimensional spectrum image names.
.le
.ls coords
List of file names containing the coordinate values. There may be
one file which applies to all input images or a matching list
of one coordinate file for each input image. The coordinate files
are a list of coordinate values with one coordinate per line.
The coordinates must be ordered in increasing or decreasing value.
The number of coordinates must match the number of pixels in the image.
.le
.ls label = ""
Optional coordinate axis label. A typical value is "Wavelength"
for wavelength coordinates.
.le
.ls units = ""
Optional coordinate axis units. A typical value is "Angstroms". In
order to allow coordinate conversions by other IRAF spectra tasks
the value should be specified as one of the known units
(see units description in \fBonedspec.package\fR).
.le
.ls verbose = yes
Print a line as each spectrum is processed?
.le
.ih
DESCRIPTION
\fBScoords\fR sets spectral coordinates in one dimensional spectral
images as a list of coordinates in the image header. The
coordinate file(s) consists of coordinate values given one per line.
Each coordinate value is assigned to an image pixel in the order given
and so the number of coordinate values must match the number of pixels
in the spectrum. Also the coordinates must be monotonically increasing
or decreasing.
When multiple spectra are to be set a matching list of coordinates can
be specified or a single coordinate file for all images may be used.
The coordinate system set in the header is an example of the "multispec"
world coordinate system. This is understood by all the standard
IRAF tasks. It is described under the help topic "onedspec.specwcs".
Once the coordinates are set one may resample the spectrum to a
more compact linear description using the task \fBdispcor\fR.
Since the coordinate values are stored in the header (double
precision numbers) the header can become quite large if the spectrum
is long. Be sure the environment variable "min_lenuserarea" which
defines the maximum size of the image header in number of characters
is large enough to hold all the coordinates.
.ih
EXAMPLES
1. Set the coordinates for a spectrum.
.nf
cl> type coords.dat
4000.
4010.123
4020.246
4031.7
<etc>
cl> scoords spec coords.dat label=Wavelength units=Angstroms
cl> listpix spec wcs=world
4000. 124.
4010.123 543
<etc>
.fi
.ih
REVISIONS
.ls SCOORDS V2.11
This is a new task with this version.
.le
.ih
SEE ALSO
rtextimage, dispcor, specwcs, onedspec.package
.endhelp
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