On Wed, Oct 17, 2012 at 12:58 PM, Martin Koppenhoefer < [email protected]> wrote:
> 2012/10/17 Igor Brejc <[email protected]>: > > Another thing that's odd is the duality of inner rings: they represent > > holes, but they can also represent holes AND separate polygons at the > same > > time. Decision on which is which has to be made based on a vague notion > of > > "difference" in tagging. > > > This is something I don't find odd. An inner ring is always a "hole" > in the multipolygon, but it is clear that what is inside this ring is > not "nothing" but something, and this something will often also be > tagged. But it is tagged on the ring itself (or on a different > multipolygon where it is an outer way), so I don't see where the > "decision" comes into play. Or are there implementations where the > tags of inner ways get also inherited to the multipolygon-area? > > Well, reading this (from the Wiki): > - If the inner way represents something in itself (e.g., a forest with > a hole where the hole is a lake), then *the inner way may be tagged as > such*. > > > - Otherwise the inner way(s) should be left *untagged*. > > What does "untagged" mean, exactly? That the way is completely without tags or that it just doesn't have tags that are in conflict with the outer ring? Example: if I put "source=Wikipedia" on the inner tag, that still represents a hole. However, if I put landuse=residential, then it's no longer just a hole, but a smaller polygon in itself. Jochen talked about this in a previous reply. But yes, you are right: in the end, you can always look at any hole as being "something" and not just a hole. I guess it depends on what you want to do with it. Igor
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