SHOW derives from the GO PLOT script available in GreG and Mapping.
GO PLOT (or its variants GO BIT, GO NICE and GO MAP) and GO UVSHOW
offered similar features to those of SHOW, but took data from files
or SIC image variables, depending on variables NAME and TYPE.
SHOW recognizes internal buffers of IMAGER, but also allows direct
display of Gildas Data Files.
