There are several image processing tools and good support for spatial statistics analysis. A spatial data analysis package developed by the EPA although no longer distributed by them. Geo-EAS data format is now common in the geostatistics world. Diagnostics and statistics make this a good advanced package for small data sets. An excellent starter package as well.
Instructions are very general and insufficient.
Both PC and Unix versions available, but only the PC version is available via internet. MOSS is a vector-based GIS system widely used by the US BLM and others. The workstation version is several revs ahead of the PC version, and the PC version is no longer being updated. Pre-compiled packages are available for several systems. The complete source code is also available.