Hi Gerd, I think the code in the branch is under heavy change at the moment but I want to let you know that I get some sporadic assertions: java.lang.AssertionError at uk.me.parabola.imgfmt.app.net.RouteArc.encodeCurve(RouteArc.java:345) at uk.me.parabola.imgfmt.app.net.RouteArc.boundSize(RouteArc.java:150) at uk.me.parabola.imgfmt.app.net.RouteNode.arcsSize(RouteNode.java:146) at uk.me.parabola.imgfmt.app.net.RouteNode.boundSize(RouteNode.java:139) at uk.me.parabola.imgfmt.app.net.NOD1Part.addNode(NOD1Part.java:232) at uk.me.parabola.mkgmap.general.RoadNetwork.splitCenters(RoadNetwork.java:251) at uk.me.parabola.mkgmap.general.RoadNetwork.getCenters(RoadNetwork.java:258) at uk.me.parabola.mkgmap.build.MapBuilder.makeMap(MapBuilder.java:233) at uk.me.parabola.mkgmap.main.MapMaker.makeMap(MapMaker.java:120) at uk.me.parabola.mkgmap.main.MapMaker.makeMap(MapMaker.java:82) at uk.me.parabola.mkgmap.main.Main$1.call(Main.java:220) at uk.me.parabola.mkgmap.main.Main$1.call(Main.java:1) at java.util.concurrent.FutureTask.run(Unknown Source) at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) at java.lang.Thread.run(Unknown Source) I added a logging just before this assertion to find the road which causes the error: lengthRatio==0 length==17003 at 203678974 http://www.openstreetmap.org/?mlat=43.585375&mlon=-3.224557&zoom=17 lengthRatio==0 length==18677 at 36867829 http://www.openstreetmap.org/?mlat=44.281819&mlon=-4.999981&zoom=17 lengthRatio==0 length==18510 at 36867829 http://www.openstreetmap.org/?mlat=45.963719&mlon=-3.427734&zoom=17 I hope it helps you to fix it! WanMil