[Tile-serving] [osm2pgsql] Wrong polygon generation (overfitting) with closed ways (#304)

[Stefan]

Yes, newer osm2pgsql versions seem to work! I have to lookup which version we're using in production - but it won't be the latest for sure since it's debian :-(.

I now tested it on Windows "osm2pgsql SVN version 0.83.0 (64bit id space)" and Switzerland (thanks to Geofabrik downloads). I'm getting 3635 roundabouts in planet_osm_line which comes close to what I expect.

Looking at planet_osm_polygon still returns some rows:

    psql -h localhost -p 5433 -U postgres -c "SELECT osm_id, ST_AsText(way), tags \
        FROM planet_osm_polygon WHERE junction='roundabout'" gis
Namely these 6 rows: -3267310, -1700414, -2442909, -1658589, -2887574, 136646975.
First 5 relations (all negative) have "type=multipolygon" which is incorrect in the data.

One other use case is way http://www.openstreetmap.org/way/136646975 being part of http://www.openstreetmap.org/relation/319761, The relation contains no "type=multipolygon" but way 136646975 contains "landuse=grass". 

This landuse should be deleted or "area=no" added (and needs an explanation in the Wiki page http://wiki.osm.org/wiki/Tag:junction%3Droundabout ).

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Reply to this email directly or view it on GitHub:
https://github.com/openstreetmap/osm2pgsql/issues/304#issuecomment-75442908
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