Geodesy based library (geodetic and geocentric functions)
FastVersion is a Qgis plugin for data versioning in a Postgis database
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
Create EPANET models in QGIS
A frontend for gpsbabel
Treating your secrets like US Governments Top Secrets