Yes, I am having a disagreement with my husband about how far we ran this morning. <img alt="wink.gif" src="http://files.kickrunners.com/smilies/wink.gif"><br><br>
His GPS seems to be underestimating the mileage, based on my usual pace.
I am not an expert on GPS measurement systems, but the method is simply to find a point in space based on three or more known vectors. If the vectors do not perfectly align at a ingle point then some formula probably kicks in to eliminate the error by adjusting one or more of the vectors.<br><br>
It seems to me that the math would not work out very accurately then, if vertical displacement were not taken into consideration.
I believe the GPS only takes into account the horizontal distance.<br><br>
If we're talking trig you have to run some pretty epic hills to make the distance much bigger! <img alt="surprised.gif" src="http://files.kickrunners.com/smilies/surprised.gif">
Does it really matter? It's only training mileage after all; who cares if it's within 500 metres either way.<br>
I'd be inclined to estimate your mileage based on your usual pace.<br><br>
Another reason why we don't have world records in road and cross country events.