Site has examples how they are overlaying data to produce interaction routes. Researchers used information from the SPOT satellite in both the 10m and 20m modes. This site is easy to use and a must for fans of the raster based GIS systems. Grass allows users to analyze, store, update model and display data. Site provides users with a tutorial and sample datasets.
Downloadable software is available in many formats and can be accessed through the site.
The Department of the Army originally used system. It can be utilized for many applications such as engineering, hydrology and remote sensing. Plenty of examples to look through and ponder. If you are looking for a variety of ways to use GPS than this is the site for you, GPS Application exchange shares information on how GPS principles can be applied to everyday research projects. Has a nice feature built into the site where the user can search by country and specific use.