Hi all, I've coded a new algo to detect and remove sharp angles in roundabouts caused by rounding coordinates to map units. There are many special cases, but I think it works quite well now. Please test mkgmap-high-prec-coord-r2819 . I found two typical problems: 1) Small roundabouts (radius < 10m) mapped with (too) many points, this gives ways like in 157324858_o.gpx 2) Large roundabouts (radius > 16m) mapped with too few points. Note that some of these problems cause routing problems in the trunk version but not in the branch. I've left a lot of debugging messages in the code, so you should write the sysout to a file (I'll change the code to use the logging system later) I have also left an option --x-gpx-dir=<dir-for-gpx-files> to create gpx files showing the ways in various stages. Note that this option produces many small files, so use it only with one or a few input files. The gpx files have a name scheme: [way-id]_o.gpx: original way, once with high precision coordinates, once with the rounded values [way-id]_del1_[n]_[pass].gpx: way before a remove-point-action [way-id]_del2_[n]_[pass].gpx: way after a remove-point-action [way-id]_m.gpx: final roundabout, once with high precision coordinates, once with the rounded values, plus map unit grid You should not find many of these: [way-id]_repl_o_[pass].gpx, id]_repl_n_[pass].gpx way that is connected to a roundabout, and the move of the node causes a notable change in the angle near the roundabout. I found no case where this lead to uglyer angles, typically, the changed way was closer to the one in OSM . Open question: The algo doesn't add points to make a roundabout rounder. It just complains like this: Way http://www.openstreetmap.org/browse/way/136791460: roundabout has rather few distinct points: 9 (radius ~ 17 m) Way http://www.openstreetmap.org/browse/way/136791476: roundabout has rather few distinct points: 8 (radius ~ 20 m) Both examples also show why adding points is not a good idea. The rule for these messages : if (radius < 10.0) niceNumSides = 8; else if (radius < 13.0) niceNumSides = 12; else if (radius < 20.0) niceNumSides = 16; else niceNumSides = 20; if (points.size() < niceNumSides){ if (points.size() < 16) System.out.println(msgPref + ": roundabout has rather few distinct points: " + points.size() + " (radius ~ "+Math.round(radius)+" m)"); niceNumSides = points.size(); } Are these rules okay? Are the messages helpful? Gerd