Hi, On 08/23/2016 09:39 AM, patrick keshishian wrote: > What is the mechanism used, while processing "relation"-s, in > matching "inner" and "outer"-s of polygons?
There's no guarantee that role="inner" and role="outer" are even set. I strongly advise against trying to write your own algorithm that combines polygons; you will get 80% right quickly and fight with the other 20% for weeks. Rings can be nested (valid), self-intersecting (invalid) or missing bits (invalid), they can have missing or wrong inner/outer tags (usually considered valid)... the C++/Python library "osmium" is probably the most advanced in building proper polygons, or check out osm2pgsql, imposm, or ogr2ogr which also have code to deal with that. Bye Frederik -- Frederik Ramm ## eMail frede...@remote.org ## N49°00'09" E008°23'33" _______________________________________________ dev mailing list dev@openstreetmap.org https://lists.openstreetmap.org/listinfo/dev
