On Wednesday, 3 May 2017 07:05:31 UTC+1, Osmandtrier wrote: > > And there is a mistake. Opening a recorded gpx-file with an other > gpx-viewer, the other party gpx-viewer shows a different difference of > altitude than osmand. > > So my idea was, perhaps osmand use the srtm-data. So I replaced the > recorded elevation-data with srtm-data. I got also a different difference > of altitude than osmand. > > GPS altitude readings fluctuate a lot, so when apps like OsmAnd generate numbers for the total amount of ascent and descent, they usually use some filtering to distinguish errors/inaccurate readings from genuine changes in altitude.
I completely expect different apps to produce slightly different results, as they use different filtering thresholds and different algorithms. Elevation figures calculated with SRTM data will be different. SRTM is based on measurements every 20-50m across the earth's surface. Presumably this has been interpolated into the OSM ways in OsmAnd's maps, so it will be less precise than GPS altitude measurements from when you've actually walked or cycled the route (though it also depends on how good a GPS fix you had). Nick -- You received this message because you are subscribed to the Google Groups "Osmand" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
