I did look at turn restrictions. But would the Garmin auto-routing algorithms even consider those restrictions?
Not without pain to implement either. The editors would need to make this a one or two click solution. Not complaining, just thinking aloud. Marc. On Thu, Apr 8, 2010 at 3:36 PM, Richard Weait <[email protected]> wrote: > On Thu, Apr 8, 2010 at 4:33 PM, Marc Provencher <[email protected]> > wrote: > > I recently posted with an open question asking how others map junction > nodes > > at complex intersections. > > > > Today I was trying to reproduce certain routing errors which I observed > > while driving, and was able to cause Mapsource to route me through an > > illegal U-turn, because of a misplaced junction node where there > shouldn't > > be one. > > > > This picture shows the U-turn: > > > http://provencher.smugmug.com/Other/Misc/IllegalUturn/831296827_sYc5e-X3.jpg > > > > The problem lies with the access ramp,which has a junction node on both > ways > > of the divided residential road. And for some reason the routing > algorithm > > doesn' t consider this a U-turn, even thought the "avoid U-turns" > setting > > is enabled. > > > > Actually, the real problem is that the routing algorithm is using these > > "connecting ways" between the two sides of a divided road, to make a > > U-turn. I'm not sure if this problem can be resolved easily. > > > > In my attached picture, removing the junction node which I thought was > the > > problem simply moved the problem to another intersection. > > I see this fault from navigation systems too. I'm not sure that the > commercial vendors worry about this error. Their systems seem to > suggest those illegal turns often enough. > > We can do better, and eliminate these routing errors with turn > restriction relations. > http://wiki.openstreetmap.org/wiki/Turn_restrictions > > See what you think. > -- Marc Provencher [email protected]
_______________________________________________ Talk-ca mailing list [email protected] http://lists.openstreetmap.org/listinfo/talk-ca
