Hi Eric, I see these u-turns in maps which add multiple routable ways with different roadclass/speed for the same OSM way. Another reason can be a parrallel cycle way. The Garmin algo sometimes prefers to take the "better" road too long and go back on the "minor" road.
The "avoid u-turn" option should help here. Gerd ________________________________________ Von: mkgmap-dev <[email protected]> im Auftrag von [email protected] <[email protected]> Gesendet: Freitag, 4. Juni 2021 13:33 An: 'Development list for mkgmap' Betreff: [mkgmap-dev] BaseCamp_Route_Is_Reversing, GPS_Route_Is_Reversing Since a very long time (assumption: 2014, BaseCamp 4.3.3) BaseCamp routing will - sometimes - reverse, bites its own tail. I have always assumed this is a Garmin BaseCamp error. It started with a specific BaseCamp version. But it may have coincided with a mkgmap update ???? Garmin has always been assuming it’s mkgmap that is responsible for this. Do these issues have any relation to mkgmap? To avoid the error: - Remove the viapoint after which the route is reversing (goes backwards). - Put viapoint ON junction, not in the middle or beginning of a highway. - Avoid putting a viapoint besides the highway. To reproduce: try not to avoid, sometimes the error occurs. Attached: BaseCamp_Route_Is_Reversing.png BaseCamp_Route_Is_Reversing.gpx Route direction: from east to west. East or arrow: route is correct. West of arrow: route is reversing. Map used for reproducing: OSM_MKGMAP_DEFAULT (But it’s reproduced on all maps (my own Bike_Map, OpenFietsMap, OSM_MKGMAP_GENERAL). I've seen it happen on GPSMAP 66s as well. Attached: BaseCamp_Route_Is_Reversing_12307.bmp Route navigation here comes from the south and should turn right (east) over the bridge. But GPS indicates to go straight on and after 80 meters: turn round, reverse, U-turn. No nodes close junction; highway south = unclassified, highway north and east = secondary Eric (AnkEric) _______________________________________________ mkgmap-dev mailing list [email protected] https://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev
