Putting a very high cost on making sharp turns from a motorway onto anything other than a motorway_link has helped for me somewhat, but it's hard to know with other types of road.
The less trivial answer is that you can edit the data to take out the nodes at vertically-separated crossings. There are (too few) people trying to clean up the TIGER data, but it's a slow process. Actually, this wouldn't be a bad place for the crowdsourcing mentioned elsewhere on this list in the last couple days. Giving users the ability to mark errors in the data and have it corrected -- without requiring them to edit the underlying OSM data themselves -- wouldn't be bad, and some of it could even be done automatically (though this may not always be wise.) On Wed, Dec 3, 2008 at 16:55, Charley Hughes <[EMAIL PROTECTED]> wrote: > I was thinking of using openstreetmap as a data source for a routing > application but found that most of the data in my area is imported from the > Tiger census data. This data does not distinguish between overpasses and > intersections. Some future iteration of the tiger data may include > information about overpasses and underpasses, but for now, every line that > crosses another has a node joining them, even if they are different types of > lines, roads, railways, rivers. This data is in the openstreetmap database > in this same form. > > I suppose one could look at the type of line to keep from routing a car down > a railway, but the under and overpasses look like routable elements when > there is no way to actually traverse them. Has anyone encountered and > solved this? > > > _______________________________________________ > Routing mailing list > [email protected] > http://lists.openstreetmap.org/listinfo/routing > > -- David J. Lynch [EMAIL PROTECTED] _______________________________________________ Routing mailing list [email protected] http://lists.openstreetmap.org/listinfo/routing
