OpenJUMP is a community driven fork of JUMP the "Java Unified Mapping Platform" GIS software. The original JUMP was developed by Vivid Solutions, released under GPL2 in 2003 and discontinued in 2006. During 2004 already some enthusiastic developers joined together to enhance further the features of JUMP. They launched an independent development branch called OpenJUMP. The name gives credit to the original JUMP development, and at the same time describes the objectives of this project to be fully open to anyone wanting to contribute. These days OpenJUMP is developed and maintained by (some few) volunteers around the globe. If you need functionality or even better want to contribute you are very welcome to contact us at our mailing list.
GPX viewer and analyzer
GPXSee is a GPS log file viewer and analyzer that supports GPX, TCX, KML, FIT, IGC and NMEA files.
Viking is a free/open source program to manage GPS data. You can import, plot and create tracks, routes and waypoints, show OSM, Bing Aerial and other maps, geotag images, see real-time GPS position (not in Windows), make maps using Mapnik (not in Windows), control items, etc. It is written in mostly in C (with some C++) & the GTK+2 toolkit.