Running Routes: Why are the miles incorrect?

Every single route I have mapped has incorrect mileage, specifically too high. If we get a certified 5 mile route,MapMyRun will compute it as 5.4 or thereabouts. Is the correct conversion factor for North America being used? Typically converting long/slats will create incorrect mileage when the wrong factors are used. I have mapped for years and seen this type of thing happen with incorrect software or wrong flattening projection methods. Maybe it is as simple as making a comparison ratio between actual and MapMyRun results and averaging the results.

Make sure you map on the highest zoom you can and sometimes mapping by the satelite immage is the way to go.  I mapped a certified 5k here in Nacogdoches and came up with exactly 3.1 using these methods.

 

yeah i use the satellite as much as possible. sometimes the roads can be way off the sattelite image.