Hi, see first http://gis.19327.n5.nabble.com/merge-lines-and-routing-tp5758913p5759595.htm... I think the reason is the remove-short-arcs processing. This can move a road, esp. if you use a rather large value like --remove-short-arcs=5.4. In the example case, way http://www.openstreetmap.org/browse/way/27904971 is moved towards http://www.openstreetmap.org/browse/way/217767494 Now, the overlaid line with type 0x10650 (really this invalid extended type?) is not a road and stays where it belongs. Another possible effect would be that the road is deleted while the copy is not. I think the solution is to make sure that 1) all lines created from the same OSM way have the same points after short-arc-removal was done with roads only 2) if short-arc-removal deletes a road (e.g. because it only has one short arc),the other lines for the same OSM way are deleted as well. Attached is a patch that implements this, a compiled binary is here: http://files.mkgmap.org.uk/download/120/mkgmap.jar Gerd