EXTLIST-Adds non-contiguous lines of an image to form a spectrum

Description:

The EXTLIST command extracts specific cross-sections of an image, adding them together to give one spectrum. The cross-section numbers are specified by an array of section numbers - this allows up to 40 non-contiguous cross-sections to be specified, rather than the single range allowed by EXTRACT.

Parameters:

IMAGE

The name of a 2-dimensional image. A number of rows (cross-sections) will be extracted from this image and added to form a single spectrum.

NROWS

Used to specify the number of cross-sections (rows) to be added together to form the single spectrum. It has to be specified here because the defaulting of values for the list makes it impossible to know otherwise how many of the values you actually intend to be used.

SECTIONS

The cross-sections of IMAGE specified by the array of row numbers given in SECtions will be added together.

SPECTRUM

Used to specify the name of the resulting 1-dimensional array. A new file will be created.

Source comments:

 E X T L I S T

 Adds the rows from IMAGE specified by the array of row numbers
 in SECTIONS and produces a 1-D data object called SPECTRUM.

 Command parameters -

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

 'NROWS'    The number of rows to be added.

 'SECTIONS' The array of row numbers.

 'SPECTRUM' The name of the resulting data.

 Output data -

 SPECTRUM is created with the same structure as IMAGE,
 except that data array will only have one dimension, and if
 IMAGE has Y-axis information, this will be omitted.  Any X-axis
 information will be copied unchanged.

                               DJA / AAO 10th July 1987