Elevation data recorded from your phone is often very inaccurate, so we decided to NOT use it and instead generate elevation for each lat/lng point in your ride. This is what many other ride tracking sites like Strava also do.

Note that the elevation-adding feature will erase any existing altitude data (for example, from a GPS). Often, this is desirable; profiles made with DEM data are usually "smoother" looking than GPS, and typically contain fewer gaps or suspicious readings.

We currently use Google's elevation API service, Google's data comes from a variety of sources and is sometimes (but not always!) more accurate than the SRTM databases. We however hope to someday create our own DEM (digital elevation model) database from all the ridelog data we are collecting. But until then we've decided to re-generate all ridelog elevation data, even if it came from a Strava synced activity. This way all the ridelog data on Trailforks is at least somewhat comparable with each other.

Ride statistics like elevation gain or descent are not a given value like distance, but something that is calculated with a formula. Each GPS app will use different criteria and formula to calculate their numbers. This often involves some cleanup of the elevation data first, smoothing out the data, then usually there is a minimum distance between GPS points for a point to be counted towards the rides cumulative climb or descend. Some apps might also have a better more accurate source of elevation data for some areas of the world.

You can read more about GPS elevation here:
- http://www.gpsvisualizer.com/elevation
- https://support.strava.com/hc/en-us/articles/216919447-Elevation-for-Your-Activity
  • By canadaka Trailforks Plus
  • #90 - 785 views