On Fri, Jul 30, 2010 at 8:44 PM, andrzej zaborowski <balr...@gmail.com> wrote: > On 31 July 2010 02:33, Nathan Edgars II <nerou...@gmail.com> wrote: >> On Fri, Jul 30, 2010 at 8:28 PM, andrzej zaborowski <balr...@gmail.com> >> wrote: >>> I don't see how it changes anything. If a piece of interstate I-405 >>> is described by one relation or two ways one for each carriage in osm, >>> and 10 segments in TIGER, than that's a way to describe it. >> >> So how would you do any of the applications described above? They all >> require either a single TLID or everything to be tagged with a field >> that includes the correct TLID (due to joining, splitting, and >> redrawing, the latter is not true). > > So your program tries to come up with a route, it knows it's driving > on road A in osm. > A has id=1 and is tagged "tiger:tlid=20:21:22:23", and it is connected > to road B (id=2, tiger:tlid="24:25:26:27") by node id=3. You also see > that tiger way 23 meets 24. That clearly means that from osm road A > you can go into tiger way 24 when you reach node id=3, without even > looking at the geometry and fuzzy guessing things (remember routing > works on huge graphs).
But road A has been rerouted since the TIGER data was created and now ends at road C, without touching road B. You can't use shortcuts like this. Or am I misunderstanding your example? If you already know A and B are joined at node 3, what do the TLIDs tell you? > > Or say that the government releases a database that says how many > traffic signals there are on each segment of road. Then you can find > the junction nodes on which they should be in OSM, or at least count > how many there should be on a given street. TLID 24 has two lights and TLID 25 has three. Joined TLID 24;25 might have four or five. Add one to the possible error for each new segment. Then split out bridges and it becomes unmanageable. > > And yes, street names are not 100% correct or complete in OSM today.. > we don't remove them though. So are you saying you or someone else will be checking all TLIDs against the TIGER data and correcting errors and adding missing ones? _______________________________________________ Talk-us mailing list Talk-us@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-us
