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

[Stefan]

osm2pgsql is incorrectly (and unintentionally) bulding polygons out of single closed ways (e.g. junction=roundabouts) when they are additionally part of a relation (disregarding if relation is multipolygon or a (bus) line).

Look at these two roundabouts (both single closed way):

1. http://www.openstreetmap.org/way/24932843
    ...
    Part of
      Relation Bus 992: Rapperswil - Jona Bahnhof (2691985)
      ...

2. http://www.openstreetmap.org/way/217996619
    ...
    Part of
      Relation Bus 992: Rapperswil - Jona Bahnhof (2691985)
      Relation 2887574 (as outer)
      ...

BTW: For Switzerland there are currently ~2729 in table osm_polygon (where they don't belong) and ~1245 roundabouts correctly generated into table osm_line. And the intersection of roundabouts in both tables is currently 1 single relation. Tested with: "SELECT osm_id FROM osm_line WHERE junction='roundabout' AND osm_id IN (SELECT osm_id FROM osm_polygon WHERE junction='roundabout')".


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