GPX stands for GPS eXchange Format, a data format used for GPS devices. GPS stands for Global Positioning System, a satellite based navigation system. You can upload your GPX files to this site and it will analyse them for you. View this example.
Features
Averages elevation of a location recorded at different times: elevation will become more reliable each time you repeat a route. Read more.
Adds up files, tracks and tracksegments, and you can view them separately too.