GPS Tracker - GPS Track Log Viewer
One of the things that I love about GPS data is that they’ve pretty much decided on a standard – the NMEA data format. When I first got my Navman GPS for my iPAQ, I thought it was cool. I thought that the included navigation software was cool, and I thought that seeing my exact coordinates was cool. That could have been the end of it, and I would have been happy.
However, most GPS devices dump their data out in a standard CSV format. This makes it very easy for 3rd party software developers to treat a GPS device as a commodity. Rather than dealing specifically with Garman / Navman / etc, they just read the standard. It’s great.
It also makes it trivial to write your own apps that interface with a saved data file. I wrote a really small app to overlay a car trip on a map, including red dots where I stopped. Now you can really say, “I’m serious – look at how bad traffic was!” I’ve heard of other innovative programs, too, like correlating the timestamp on a picture from a digital camera with the GPS log to give you the coordinates where the picture was taken.
The most useful GPS data is the “RMC” string:
Recommended Minimum Specific GNSS Data (RMC)
- UTC time of position fix, hhmmss.sss format.
- Status, A = data valid, V = data not valid.
- Latitude, ddmm.mmmm format.
- Latitude hemisphere, N or S.
- Longitude, dddmmm.mmmm format.
- Longitude hemisphere, E or W.
- Speed over ground, 0.0 to 1851.8 knots.
- Course over ground, 000.0 to 359.9 degrees, true.
- Date, ddmmyy format.
- Magnetic variation, 000.0 to 180.O.
If you’re interested, the data format is here.