wrong statistic calculation

[mgroeger4orux]

When saving a track the values of elevation gain/loss are significant decreased.

But if you simply add the elevation differences between the single points from the gpx, then you get the original value.



In an extreme example the elevation gain calculated from the track point of the gpx is 1371,35m while the header of the gpx contains the value 971m, which is somehow calculated by oruxmaps.

I remember that I've seen during the tour the 1200m value for the elevation gain was displayed and there was some elevation gain after this point.



Any idea, what's going wrong?

[gicif]

When saving a track the values of elevation gain/loss are significant decreased.

But if you simply add the elevation differences between the single points from the gpx, then you get the original value.



In an extreme example the elevation gain calculated from the track point of the gpx is 1371,35m while the header of the gpx contains the value 971m, which is somehow calculated by oruxmaps.

I remember that I've seen during the tour the 1200m value for the elevation gain was displayed and there was some elevation gain after this point.



Any idea, what's going wrong?

Unless you have a barometer in your device, the altitude calculation made by GPS alone is very inaccurate.

So you should rely on DEM files for the altitude calculation: it will not be perfect, but it will be a good estimation.



best regards

[orux]

When saving a track the values of elevation gain/loss are significant decreased.

But if you simply add the elevation differences between the single points from the gpx, then you get the original value.



In an extreme example the elevation gain calculated from the track point of the gpx is 1371,35m while the header of the gpx contains the value 971m, which is somehow calculated by oruxmaps.

I remember that I've seen during the tour the 1200m value for the elevation gain was displayed and there was some elevation gain after this point.



Any idea, what's going wrong?

Unless you have a barometer in your device, the altitude calculation made by GPS alone is very inaccurate.

So you should rely on DEM files for the altitude calculation: it will not be perfect, but it will be a good estimation.



best regards

It is right;



the values obtained by the GPS need correction.



You can upload the gpx to different web sites, like gpsies, ibpindex,... and you will see that all of them try to correct the elevations.





orux

[mgroeger4orux]

The smartphone has a build in barometer, which seems to work quite good. So the original values are reasonable. If I later plan to use this track for a tour, then it's a big difference whether there are less than 1000hm or almost 1400hm.



The save dialog for a track contains the option for correction of mesured hight values. That's good. So I would expect, that I can decide whether the values will be recalculated (and even which algorithm will be applied) or whether they are kept untouched. Is it possible to get this option?