Clinton Gladstone <[email protected]> writes: > On Fri, Aug 14, 2009 at 2:44 PM, Greg Troxel<[email protected]> wrote: > >> I most recently built with all 6 NE states (conn, ri, mass, vermont, new >> hampshire, maine) all together, invoking the script 'do-mkgmap' which >> follows as something like >> >> $ do-mkgmap *.osm.bz2 > > In this case, routing will not work across state boundaries. You know > that though, right?
No, I didn't know that. But now that I think about, I think I can see why. Is the issue that the extracts are split with polygons and osmosis, and there is no overlap and synthetic nodes at the boundary? I wonder if the polygons overlapped enough to make sure that there was a node in common, if that would make things work. But that's almost certainly not the big issue - if I can get to where intrastate routing works in each state that would be great. > I compiled Massachusetts and experimented with routing in Mapsource (I > will try Roadtrip later). I found that routing only works for very > short distances (even without crossing tile boundaries). For example, > I tried the I95 around Boston. There, I could only route along > segments which were less than 1 km long. I'll take a look, and also try shorter routes not on the motorways. MassGIS data has the one-way property but not the direction. I've straightened out a lot of 495 and 2 but not I95 (=MA128). So motorways are particularly likely to be trouble, compared to normal state highways or regular roads. > It seemed, although I have not tested enough to confirm, that it was > hardest routing along the more curved sections of highway. This would > support the hypothesis that the node density is too high for proper > routing. I have not had time to download the OSM data to take a look. > I wonder if a way simplification patch could help here. I suppose I could run --remove-short-arcs with 20m. Or a new option that drops nodes within 50m as long as they only have 2 arcs and the resulting position of the midpoint doesn't move by more than 2m, or something like that. > I'm surprised that you were able to create routable maps using > --max-nodes=1600000. I had to lower max nodes to 800000 in order to > compile. I didn't realize that 1600000 was too big. My machine has 4G ram with a heapsize of 2G. Is it safe to assume that if it completes without error that things fit? In Mass I think the ratio of nodes to ways is much higher than in other places, so perhaps that explains it. Thanks very much for looking into this - now I'm pretty sure that I'm not doing something dumb, and that digging into it more is sensible.
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