Geographic library
Viking is a free/open source program to manage GPS data
An information system for cyclists in Berlin and Brandenburg
A GUI for the freeware Geographical Information System PCRaster
Plugins for OpenCPN
Geodesy based library (geodetic and geocentric functions)
Multiplatform Ham Radio APRS and Mapping Program
OTB is an open-source C++ library for remote sensing images processing
Geographic feature extraction and data mining
QNetMap is the library for displaying the map and the objects on it
OpenMTP/HRI/HRIT C++ access libraries.