Quote:
Originally Posted by formula154
As far as the GPS is concerned, doesn't a GPS just tell you the distance point B is from point A? Example if you rode on a round track with a diamater of 1 mile which was 3.14 miles around the track wouldn't the GPS say that you travled 1 mile from point A even though you actually rode 3.14 miles because you stoped 1 mile from the starting point? It doesn't measure miles of elevation either does it?
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The GPS can tell you both things. Make a route from A to B, both as same location. Ride the loop. If you traveled ALL the way around a 1 mile diameter circle it will read approximately 0 as distance to destination B. But it will also tell you that your "mileage" is approximately 3.14 miles. These are two different readouts on my Etrex Legend GPS. And yes it DOES measure miles of elevation even though in most (non-flying) cases the 3D mileage is not significantly different from the 2D mileage. Commercial GPS units take their position fix about 1 time per second and then compute the mileage/kilometerage? between the two points. Total mileage is the sum of all the one second intervals. The faster you go the less precise the measure is going to be, because as HavBlue pointed out they end up "squaring" the corners. I guess they figured not many people fly the Concorde any more so they only rate my GPS to about 1000 mph
