Can a multipolygon outer share part of a way with an inner of the same multipolygon?

asked 01 Mar '11, 02:28

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upstream
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No. The outer and inner of a multipolygon relation must not touch or cross. No sharing of points either.

http://wiki.openstreetmap.org/wiki/Relation:multipolygon

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answered 01 Mar '11, 02:35

Richard%20Weait's gravatar image

Richard Weait
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edited 01 Mar '11, 02:39

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The reason being because if the 'inner' touches the 'outer', then it is no longer 'inner' - the 'outer' way can just divert around what was the 'inner' to exclude the inner area.

(01 Mar '11, 09:30) EdLoach ♦
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Interestingly in OSM we allow inner rings to touch. This is not conform to standard OGC Simple Features but allows for simpler modeling in OSM when you have multiple different adjacent features inside the outer way which you want to exclude from the polygon.

(01 Mar '11, 11:59) dieterdreist
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question asked: 01 Mar '11, 02:28

question was seen: 4,248 times

last updated: 01 Mar '11, 11:59

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