Hi Andrzej, did not try the patch but I wonder why you don't use the modified area for the hgtConverter as well? Gerd ________________________________________ Von: mkgmap-dev <mkgmap-dev-bounces@lists.mkgmap.org.uk> im Auftrag von Andrzej Popowski <popej@poczta.onet.pl> Gesendet: Sonntag, 14. Januar 2018 14:29:57 An: mkgmap-dev@lists.mkgmap.org.uk Betreff: Re: [mkgmap-dev] HGT - getElevation() Hi Gerd, I have attempted to reduce interpolation, when DEM pixel size is the same as HGT pixel. I have stretched a bit area of DEM, so edges are aligned with HGT. I'm attaching a patch. Resulting map looks similar, only shading has moved a bit. I'm not sure if this is the result of differences in interpolation or maybe change introduced by moving DEM borders. -- Best regards, Andrzej