AIPS HELP file for PIXRANGE in 31DEC19
As of Wed Feb 20 17:06:13 2019
Type: Adverb (Array(2))
Use: Range of image values used for various tasks and verbs.
The first element represents a minimum value and the
second element represents a maximum value. The units
are the same as those of the image. The values may
exceed the values in the image up to a fairly extreme
limit. If, for example, PIXRANGE(2) > 100 * map max,
however, the map max is used as PIXRANGE(2).
Null Value: (0,0)
Null value assignment usually map min to map max.
PIXRANGE(2) <= PIXRANGE(1) taken as "null value".