[OSM-dev] Applying outer way attributes to multi-polygons

Frederik Ramm frederik at remote.org
Tue Aug 17 19:24:27 BST 2010


Hi,

Matthias Julius wrote:
> Am 14.08.2010 08:39, schrieb Sebastian Klein:
>> The situation you describe (multipolygon: natural=water; outer way:
>> leisure=park & natural=water), is a little ambiguous, though: In strict
>> interpretation, there would be 2 water areas. This is probably not the
>> intention, so I would consider natural=water on the outer way a legacy
>> artefact and ignore it.
> 
> Well, I wouldn't.  I would call that a bug in the data.

Maybe bug is too harsh, but yes it is overspecified. There was a time 
when people said that the "inner" way should have the same tags as the 
"outer", so in addition to Sebastian's interpretation, it is possible 
that the whole area is indeed a lake with an island.

There's a rather complex specialist view in the OSM inspector for 
multipolygons:

http://tools.geofabrik.de/osmi/debug.html?view=multipolygon&lon=-1.10156&lat=52.74560&zoom=7&overlays=invalid_geometry_hull,duplicate_ways,intersections,intersection_lines,ring_not_closed_hull,ring_not_closed,unconnected_end_nodes,touching_inner_rings_hull,touching_inner_rings,role_mismatch_hull,role_mismatch,duplicate_tags_hull,duplicate_tags,multipolygons_type_is_boundary,type_is_boundary,ways,role_markers,way_end_nodes,way_nodes

This also includes highlighting polygons where inner and outer tags are 
the same.

Bye
Frederik

-- 
Frederik Ramm  ##  eMail frederik at remote.org  ##  N49°00'09" E008°23'33"



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