DEM correction

[lacdan]

Hi, having corrected altitudes with DEM files and comparing the results with Google Earth, altitudes are OK but the gain/loss in altitudes are much higher than in the non-corrected file or in Google Earth. I think this is not normal and I can't find any explanation.

Thank You.

Lacdan

[Maki]

I've seen something similar too. The common explanation is that DEMs aren't especially precise and can have pits and bumps. However I'm now using very precise LIDAR scans now and I still see strange things. I'm on holidays now, in September I'll try to test better.

[lacdan]

I have looked deeper at the rough data of a 10 km track in Belgium: with a ~10 meters interval between successive measures there are bumps and pits up to 35 m in the DEM corrected track but only max 12 meters in the non corrected track !

Lacdan

[orux]

I have looked deeper at the rough data of a 10 km track in Belgium: with a ~10 meters interval between successive measures there are bumps and pits up to 35 m in the DEM corrected track but only max 12 meters in the non corrected track !

Lacdan

Hello,



Check the 'interpolate DEM altitudes' checkbox in configuration--sensors--gps.



I think google earth uses a more detailed DEM grid.



orux

[lacdan]

I checked the interpolate dem but it doesn't work : results are the same as gps altitudes.