ISUBSET-Produces a subset of an image

Description:

ISUBSET takes a subset of an image. The result is a new image which is a rectangular subset of the original data.

Parameters:

IMAGE

The name of the image from which a subset is to be taken. IMAGE may be 1 or 2 dimensional.

YSTART

The value of the Y-coordinate for the first pixel in the input image to be included in the subset. Note that the subsetting is done on a whole pixel basis, so the resulting subset may not begin exactly on YSTART, but will start with the first pixel that covers that Y value.

YEND

The value of the Y-coordinate for the last pixel in the input image to be included in the subset. Note that the subsetting is done on a whole pixel basis, so the resulting subset may not end exactly on YEND, but will end with the first pixel that covers that Y value.

XSTART

The value of the X-coordinate for the first pixel in the input image to be included in the subset. Note that the subsetting is done on a whole pixel basis, so the resulting subset may not begin exactly on XSTART, but will start with the first pixel that covers that X value.

XEND

The value of the X-coordinate for the last pixel in the input image to be included in the subset. Note that the subsetting is done on a whole pixel basis, so the resulting subset may not end exactly on XEND, but will end with the first pixel that covers that X value.

OUTPUT

The name of the resulting subset image. If this is different to IMAGE, then a new file will be created, with everything bar the data a copy of the original image. If OUTPUT is the same as IMAGE, then the input file will be modified to contain just a subset of its original data.

Source comments:

 I S U B S E T

 Creates a subset of an image.

 Command parameters -

 IMAGE  (Char) The name of the structure containing the image.
 YSTART (Numeric) The AXIS(2) value for the start of the subset.
 YEND   (Numeric) The AXIS(2) value for the end of the subset.
 XSTART (Numeric) The AXIS(1) value for the start of the subset.
 XEND   (Numeric) The AXIS(1) value for the end of the subset.
 OUTPUT The name of the result of the operation.  This can
        be the same as for IMAGE.  If not, a new structure
        is created, with everything but the data a direct
        copy of the input.

                                  KS / CIT 19th June 1984