PDL::Graphics::IIS provides an interface to any image display 'device' which
support the 'IIS protocol' - viz the SAOimage and Ximtool X-windows programs,
the old SunView imtool program and presumably even the original IIS CRT itself
if they aren't all in museums!

These programs should be familiar to astronomers - they are used by the common
IRAF system.

Non-astronomers may find they quite nifty for displaying 2D data.