Hi Andrzej, I don't see any specific difference in the behaviour, but overall the JOSM algo removes a few more points compared to the mkgmap version. With r4763 you can simply replace the call to shortestDistToLineSegment() by distToLineSegment() in DouglasPeuckerFilter.java Reg. speed it probably doesn't matter that much. I looked at this because VisualVM claimed that Douglas-Peucker is responsible for a lot of run time but now I think that VisualVM was wrong. Gerd ________________________________________ Von: mkgmap-dev <mkgmap-dev-bounces@lists.mkgmap.org.uk> im Auftrag von Andrzej Popowski <popej@poczta.onet.pl> Gesendet: Dienstag, 8. Juni 2021 21:43 An: mkgmap-dev@lists.mkgmap.org.uk Betreff: Re: [mkgmap-dev] Wrong Douglas-Peucker implementation? Hi Gerd, Josm's algorithm removes some spikes, which probably aren't common for real data and layer 0 of img. So differences aren't big. But maybe for lower resolution it could be better, especially for polygons. Wouldn't it be faster? -- Best regards, Andrzej _______________________________________________ mkgmap-dev mailing list mkgmap-dev@lists.mkgmap.org.uk https://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev