Marvellous discovery. The GPX format. An xml schema for GPS data. I just used it with my GPS. A garmin legend c. To sample this out I used Debian 3.1 and an excellent tool called gpsbabel version 1.3.2. It worked right out of the box.

sudo apt-get install gpsbabel

sudo gpsbabel -t -r -w -i garmin -f usb: -o gpx -F gironde.gpx

The format stores way points with latitude longitude name description current time symbols and elevation.

Tracks are stored as track segments with track points containing the latitude longitude time and elevation.