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.
- OpenStreetMap (OSM)
- Mapnik Rendering
Looks great and downloaded my Garmin tracks in a flash - but couldn't read my device directly and (more critically for me) the app fell over after 10minutes use! uninstalled! So it's free... but unstable. (The point would be to replace Garmin basecamp but while I don't like it at least it stays up...)
The Viking GPS data editor is a great tool for managing GPS data. I've been organizing botanical collecting using known collection sites, using coordinates from herbarium collections of hundreds of species of plants. The one difficulty I've had is configuring real-time GPS on my MacBook Pro that runs Mavericks. As far as I can tell, this is impossible. The only potential fix I've heard of is to install a virtual machine running a linux flavor. I haven't gotten that far yet.