[OSM-talk] area_with_holes as alternative to multipolygon relation

[Robert Vollmert]

Hello,

http://wiki.openstreetmap.org/index.php/Relations/Proposed/ 
Area_with_holes contains a proposal for an alternative to the current  
multipolygon relation. Please tell me what you think about it. Am I  
missing something?

In short, the proposed changes are the following:

type=multipolygon
   -> type=area_with_holes
role=outer, way, clockwise
   -> role=boundary, way, clockwise
role=inner, way, anti-clockwise
   -> role=hole, way, clockwise
same tags on inner and outer ways; these describe the multipolygon
   -> tags on boundary describe the area, tags on hole describe the hole

This would also solve the naming ambiguity, though my aim is mostly  
to make things easier to tag. In particular, with the proposed  
relation, it's not necessary to create duplicate ways (clockwise and  
anti-clockwise) for holes with properties.

I'm actually in favour of dropping orientation restrictions  
completely: The area corresponding to a closed way should be the  
closed area it bounds in, say, the hemisphere all nodes lie in.  
However, as it stands, the proposal should be straightforward to  
implement for any renderer that can deal with the multipolygon relation.

Cheers
Robert