Originally Posted by
Xherion
Elevation databases
For devices without barometric altimeters, we consult elevation databases to determine the elevation at each point in the activity. The resolution of these databases can vary based on location. For example, the USGS National Elevation Dataset (NED), which we consult for activities located in the US, generally has a 10 meter resolution though some small areas have a 3 meter resolution. For activities located outside of the US, we consult the ASTER and SRTM databases which have a resolution of anywhere from 30 to 90 meters.
https://support.strava.com/hc/en-us/...-Your-Activity
Hmm.. Seems Strava themselves would have the best, or at least the most extensive database of reported elevations for any given segment of road, than any other source. I find it curious they revert to the USGS for the data.