So my question is when you map a run out on the USATF site, or the google earth is it reliable..... i have wheeled several runs and used google earth sometimes its accurate and alot of the times there be as large as a 600 meter difference between the wheeled measured run and the google earth run..... am i doing something wrong.....
Predict my time?? Joke Joke Joke
That's crossed my mind as well. What I did was found my local track and measured it using google. Line to line was 99.97 meters. Just keep in mind that it won't take into account uphills/downhills.
if you use gmaps pedometer it is very reliable.
I measured my track and got 396m, so take that for what it's worth.
The more curves/elevation, the less accurate.
Not on Google Earth, but on gmap-pedometer.com (same thing, basically) I marked up a local 400m track at the highest zoom level. It said 400.4 meters. Considering it connects the points with straight lines I'd say that's pretty fu\cking accurate.
If you can see the path clearly (i.e. no tree cover, etc.) many measurers have found Google Earth to be accurate enough for course layout to wi/in 1 or 2 meters per km - that's pretty damn good (and WAY better than most GPS units).