QLandkarte GT is a powerful Open Source GIS application to display your GPS data on a variety of maps. It's target is the less the scientific user but the private outdoor aficionado with a crush on hightech equipment. It's easy to plan, evaluate and archive your trips into the wild green by QLandkarte.
QLandkarte GT supports GPS maps in GeoTiff format as well as Garmin's img vector map format. Additional it is the PC side front end to QLandkarte M, a moving map application for mobile devices.