Hi all, see http://www.mkgmap.org.uk/websvn/revision.php?repname=mkgmap&rev=4042 Details are discussed here: http://www.mkgmap.org.uk/pipermail/mkgmap-dev/2018q1/027628.html Thanks to Andrzej for this patch, I think it is another good improvement. A nice side effect of the better interpolation is that DEM sizes are a bit smaller. So, maybe also try higher dem-dist values now. Gerd