2009/10/14 sly (sylvain letuffe) <[email protected]>: > In the holes continuity, it as been proposed that an area representing > something inside another area would still be part of a multipolygon relation > but with it's own tags.
no, this is not the case. Multipolygon says: the inner part is NOT part of the outer polygon. If it is part just don't put a multipolygon-relation (standard-case). > this sounds great, requesting the surface of the big area is strait forward, > rendering become easy (no "which one is over which one"), such a puzzle makes > it easy to find problems, etc. no, this is a case to be solved continuously - usually if one polygon is entirely inside another the smaller one should be rendered above: this should be generally solved by the renderers. Also, it can be better in some cases not to use a solid fill but just an outline that is rendered above the fills. > But, this becomes harder and harder for the mapper. A big forest containing > thousands lakes ? a landuse=residential containing park, cimetary, etc. ? > I fear not every one is gone a make the effort. > And after all, is it at all needed ? let the mappers decide. > In the "area inside area case" (not the partially overlapping areas case) > We can resonably imagine that if a mapper has added such an area inside > another, then either : > - they can be both (a military area and a forest) > - they can't be both (a lake and a forest) well, even in the case lake inside a forest I'm not sure, if the forest stops where there is the lake. Probably you can consider the lake also part of the forest (when it's small), or to give a different example: elementary school inside a residential area. Usually those would be considered to be part of the residential area. > Maybe if we just define/explain/(do our best not to create same key > incompatibility, juste like this boundary=military propose to replace the > ambiguous landuse=military for some cases) > Same for natural, then what we've left ? amenity? Finally almost all tags can become areas. > A lake inside a forest, is not a forest sure? > A cimetary inside a residential is not a residential +1 cheers, Martin _______________________________________________ Tagging mailing list [email protected] http://lists.openstreetmap.org/listinfo/tagging
