GEOgraphic coordinates TRANslator (documentation)

 GEOTRANZ (Geographic Translator) is an application program which allows
 you to easily convert geographic coordinates among a wide variety of
 coordinate systems, map projections, and datums. Currently, twenty-five
 different coordinate systems, map projections, grids, and coding
 schemes, and over two hundred different datums, are supported.
 .
 GEOTRANZ is the Debian name of GEOTRANS, a product of the National
 Geospatial-Intelligence Agency (NGA) and U.S. Army Engineering Research
 and Development Center.
 .
 This package contains a lot of documentation and examples.