YSTRACT-Adds contiguous columns of an image to form a spectrum

Description:

Adds a number of consecutive columns from an image to produce a 1-D data object. (A 'column' is all the pixels with a given X-value.)

Parameters:

IMAGE

Name of image to extract data from.

XSTART

First x-value to be used.

XEND

Last x-value to be used.

SPECTRUM

Name of spectrum to be generated.

Source comments:

 Y S T R A C T

 Adds a number of consecutive columns from an image to
 produce a 1-D data object.  (A 'column' is all the
 pixels with a given AXIS(1) value.)

 Command parameters -

 'IMAGE'    The name of the image from which the rows
            are to be taken.

 'XSTART'   The AXIS(1)-value of the first row to be used.
            If IMAGE has an AXIS(1) structure, the data from this
            is used.  If not, the column numbers are used,
            starting from 1.

 'XEND'     The AXIS(1)-value of the last column to be used.

 'SPECTRUM' The name of the resulting data.

 Input data - an IMAGE

 Output data -

 SPECTRUM is created with the same structure as IMAGE,
 except that the data-array will only have one dimension, and if
 IMAGE has an AXIS(1) structure, this will be omitted.  Any AXIS(2)
 structure will be copied unchanged.

                                 KS / CIT 22nd March 1984