GPS log file viewer and analyzer
Viking is a free/open source program to manage GPS data
Plugins for OpenCPN
Simple GPS tracking server
GPS mapping and management software
Open Source Marine Chart Plotting Program
This is a port of LibRTK on C#, and into a small c/c++ library.
Satellite Emulator
A tile-based map viewer with support for GPX files.
A gui for linux users of miniHomer, a GPS tracker
Visualize data from the opencellid.org project
a free and open map of wireless communicating objects