MXDtoAXL, This tool converts ESRI ArcMap views (all layers in the active view) into ESRI ArcIMS AXL configuration files, both for feature and raster layers
Geodesy based library (geodetic and geocentric functions)
geoStarsLib has functions for dealing with many geodesy-based problems found in positioning, pointing, and surveying situations. It is useful to determine absolute position on the earth, pointing vectors, coordinate transformations, and other functions.
pgArcNG -the ArcGIS(ArcMap) connector to postgis with multiuser editing ability.