Viking is an open Source program that will help you manage your GPS data. You can import, plot and create tracks and waypoints, show OSM, Terraserver and other maps, see real-time GPS position, get geocaches, control items, etc. It is written in C & the GTK+2 toolkit

Viking aims to be easy to use, yet powerful in accomplishing a wide variety of tasks. Some of the things you can use Viking for are:
1. Uploading and downloading waypoints, tracks to/from GPS.
2. Preparing tracks and waypoints for trips using maps from services such as OpenStreetMap (OSM) and/or Terrasever. The data is only needed to be uploaded to your GPS before you leave. The maps together with your tracks and waypoints can also be
3. printed and used during the trip.
4. After trips, tracks and waypoints from GPS can be downloaded, stored, managed and reused in your (or your friends') later trips.
5. Analyzing Off Highway Vehicle (OHV) and hiking trips, understanding where you went and how far you were from something.
6. Making waypoints and tracks to follow to easily get someplace you've never been before or don't have GPS data for but online maps exist for it.
7. Making maps with coordinate lines.
8. Grouping data from multiple trips using a hierarchical data manager.
9. Analyzing speed at different places (to some degree), adding waypoints where you forgot to mark one but did slow down or stop.
10. Downloading and storing OSM and/or Terraserver maps on your hard drive and looking at them later.
11. Editing tracks and trackpoints, joining and splitting up tracks
12. Show the live GPS position on the map (for use on a mobile device - e.g. a laptop)

Requirements:
* GTK+ for Windows

The license of this software is Free, you can free download and free use this graphing software.