There are several reasons:
Any programme – no matter if Komoot, Google Maps, GPSies or Outdooractive – uses different terrain models. We, for instance, use a model with a raster of 90 × 90 m, so we take one value of altitude for the entire area. This leads to inevitable deviations, especially in the mountains and partivularly at peaks and ridges.
By the way: Even if there are identical terrain models, the calculated data differs mostly as every supplier interpolates in a different way. But there are also other reasons for the deviation:
Distance between the waypoints
The distance between the waypoints is an important factor to keep in mind reguarding the precision of map data. For routing we take 50 m, which leads to a common problem: Whether a distance is short or long lies in the eye of the beholder. Therefore, we decided to use an average value.
What is “right“ or “wrong“?
The differences are also caused due to the fact that there is no such thing as an exact tour of reference. “Why don’t you record with GPS?“ one might ask. But this data is not more precise than the terrain models of our cartography. That’s because the GPS is not precise, neither in altitude nor in distance. It puts the waypoints either a little bit on the left or on the right of the way. On steep terrain (a precipice, for instance) this leads to the recording of a track which differs considerably from the one you’ve actually been walking.
The route of the satellite picture and the map is identical and is realistic (as you can see on the hybrid map). The GPX track, however, lies a little bit aside oft he actual way. Hence, the recorded track does not always guarantee “perfect” data.
How can I get values that are as realistic as possible?
Create a tour always on our trail network – by doing so, the data you receive matches the tours of our website and there won’t be deviations offroad.
For the sake of the routing’s follow-up work it’s usefol to save the track with your GPS device. You can upload the track in our tour planner and watch the aerial view to see how precise your track is.