[OSM-dev] (Multi)Polygon handling

sly (sylvain letuffe) liste at letuffe.org
Fri Jul 13 14:34:05 BST 2012


> But we need to agree on what is valid and what is
> treated as invalid. 

I think this is the first step we should start with (or at least define it 
somewhere with words while building test cases). Test cases are good technical 
tools to automatically evaluate algorithms and their multi-polygon compliance, 
but we should define, for the mappers, what is invalid and valid.

What we have here :
http://wiki.openstreetmap.org/wiki/Multipolygon
is :
"Generally, the multipolygon relation can be used to build multipolygons in 
compliance with the OGC Simple Feature standard 
(http://www.opengeospatial.org/standards/sfs). Anything that is not a valid 
multipolygon according to this standard (e.g., polygons with intersecting 
rings) should also be considered an invalid multipolygon relation, with the 
notable exception of touching inner rings (see below). "

But I raised concerns about the exact meaning of this sentence here :
http://lists.openstreetmap.org/pipermail/dev/2012-May/024948.html

-- 
sly (sylvain letuffe)



More information about the dev mailing list