> From: Martin Koppenhoefer [mailto:dieterdre...@gmail.com] > Subject: Re: [OSM-talk] osm2pgsql multipolygon parsing > > it has a different meaning. tags on a closed way are for the whole area > inside the way, tags on a mp relation are for the area of the outer > minus the inner ways.
Unless the closed way is a member of a multipolygon relation with no other tags on the relation - then you'll have a resulting area with a hole. This is a very well established means of tagging areas with holes (~22% of type=multipolygon relations have no other tags). The issues raised originally in the ticket are best explored through examples The first case is a way with natural=water and a MP relation with no other tags. Both old osm2pgsql (0.82) and latest master version from git create an area with a hole with natural=water on the area. There are no suggestions of changing this. The second is a way with natural=water and a MP relation with name=foo (with the way as a member). Old osm2pgsql created an area with a hole with natural=water, name=foo, latest master does too. The third is the second with the same as the 2nd, but a name:de tag added. In old osm2pgsql this created an area without a hole, in latest master it creates one with a hole. The fourth is a way with natural=water and a MP relation with foo=bar. In old osm2pgsql this created an area without a hole, in latest master it depends on the .style file used for import. To make #3 consistent with #2 without breaking backwards compatibility latest osm2pgsql doesn't use a pre-defined list of tags to differentiate between "old-style" and "new-style" MPs, it uses its list of tags that denote an area. The specific issue that brought this up is actually fixed by only bringing tags onto the MP area where all outer members have the tag, but there's still a more general question. _______________________________________________ talk mailing list talk@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk
