[OSM-talk] Valid geometry for closed ways
jukka.rahkonen at latuviitta.fi
Fri Aug 20 16:38:55 BST 2010
Sebastian Klein <bastikln <at> googlemail.com> writes:
> I remember someone said that "Multipolygon" would be misnomer. But
> according to this specification, it fits quite well, doesn't it?
All the polygons can be called multipolygons. Polygon is a simple variant of a
multipolygon, and it can hold only one outer ring. It can still contain however
many inner rings, even zero. It is often good for GIS users if in the dataset
only "real" multipolygons are presented as such because sometimes some spatial
functions do not accept multi-outer-ring things. But yes, OSM multipolygon
relations which are most often one-outer-ring-with-holes can be called
multipolygons also in the GIS world.
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