Hi Andrzej, hgt files are 3'' from viewfinder, the pictures show an area in Bolivia. The picture shows the location in the status line. And yes, the extended DEM data is clearly shifted relative to the OSM data. I assume now that Garmin uses this feature to match existing map data with existing DEM data. Do you want to say that you don't see a movement in your tests? Gerd ________________________________________ Von: mkgmap-dev <mkgmap-dev-bounces@lists.mkgmap.org.uk> im Auftrag von Andrzej Popowski <popej@poczta.onet.pl> Gesendet: Montag, 15. Januar 2018 21:41:48 An: mkgmap-dev@lists.mkgmap.org.uk Betreff: Re: [mkgmap-dev] HGT - getElevation() Hi Gerd, on your pictures it looks like shading form extended DEM doesn't match map features. Is it HGT with resolution 1200? Shading looks more detailed than on my map, which uses DEM created by BuidDemFile. I have to recompile my map to compare. I have done different test. I have analyzed a round peak on a map and traced coordinates of the center of highest DEM value. All at zoom 20m. Than I looked up the coordinates on HGT tile in QGIS. There were good match, coordinates were max 5m from the center of a HGT pixel. Then I checked offset of DEM, it was about 7m north and 18m west. For me it looks like shifting DEM works correctly, but I can't explain effects on your map. -- Best regards, Andrzej _______________________________________________ mkgmap-dev mailing list mkgmap-dev@lists.mkgmap.org.uk http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev