Forums >Technical Support>mileage displayed different
Any idea why the mileage in my log isn't the same as the mileage that displays on the map? It all comes from the same upload. Perhaps one comes from my watch and the other is calculated from the tracks on the map? Just wondering. Sometimes its quite large, like my 2/23 run shows 14.7 on the log and 15.0 on the map.
There are multiple ways to calculate distance between two points on the surface of the earth. The log's distance comes from your GPS, while the map's distance is calculated using RA's ellipsoid distance formula. There is no perfect way to measure distance because the earth is not a perfect sphere. The one used on RA is supposed to be more accurate but more complex, while the one used in GPSes is probably the simpler and quicker variety.
eric
http://en.wikipedia.org/wiki/World_Geodetic_System
Excellent! Thanks. I guess I was just thrown off to see two different mileages in the same log entry. Makes sense to show the watch distance someplace so we aren't complaining that the log doesn't match our watch. Thanks for the answers. Enjoying the site so far! Great job.