On Tue, Sep 29, 2009 at 8:34 PM, Ian Dees <[email protected]> wrote:
> On Tue, Sep 29, 2009 at 6:58 PM, Anthony <[email protected]> wrote: > Can we assume the shared ways use shared nodes? I was planning on making > that assumption, because I believe it's true for the particular data I'm > trying to import. Without that assumption, it's probably too much work for > the time I have. > > No. In most cases the ways do not share nodes. Almost all of the time, the > overlapping ways share node locations. > Okay, I was imprecise (a terrible thing when dealing with this topic, so my apologies). Before I dealt with those other problems I was going to be to go through my data and merge any nodes with shared locations into shared nodes. I'll probably do this while importing the data into a database, and it should be very easy. I need the database because I want to be able to extract sections of the data (individual neighborhoods at a time), and I've currently got a half gig shapefile (which converts to a 1.7 gig .osm file), which seems to have the polygons in fairly random order. I'm a little worried there might be situations like this, though: w--x | | a--b | | | | c--d | | | y--z With WY overlapping BD, but not sharing any nodes. If you think you can attack that situation, I'd be happy to help. In any case, I have to worry about converting the multipolygons from the >> shapefile I have first. I'm pretty sure there are some, in the standard >> "holes go clockwise" format, and shp2osm doesn't handle that as far as I can >> tell. >> > > My Java version of shp-to-osm handled this automatically. It appears to me > that the shapefile format follows the same model we do: clockwise for outer > rings and anti-clockwise for inner rings (e.g. "holes"). > I should probably check out the java version. Does this use the old 0.4 method, or the new multipolygon relations? I guess using multipolygon relations won't be too bad. I just leave the tags off all but one outer way (whatever one has the biggest area?), and then reference them in a relation (calculating the area to determine clockwise/anti-clockwise). Ugh, it sounds so easy until you get down to the nitty gritty.
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