[andrew15]

Unfortunately, the GPS sampling is good, but I don't think it's good for your proposed idea. It works well for things like harrys lap timer and other predictive lap timing apps, but it's not nearly as accurate as something like a traqmate.

For example, I'm in my front office right now, but my phone says I'm in my neigbours dining room about 15' away.

It may be better the the add on tomtom windshield mount, but by itself it's not acurate enough to differentiate a good line from a bad line.

PS - It's now showing that I'm in the front driveway working on my car - that's 10' in the other direction.