Le samedi 13 octobre 2012 21:49:21, Frederik Ramm a écrit : > (Frankly I am surprised > that you thought the list was necessary, as I believed everything to be > explained properly already.)
I'm not surprised, I've been asking for a while what validity means in the context of multipolygon relations in OSM (on tagging list), especially in strange border cases, but I'm still missing answers. I also guess that since changes on the wiki are recurrent about that, I'm not the only one unsure about what is and what isn't valid. But maybe I failed to reach the good list, and dev is better suited for that as the answer is far from trivial, and is indeded more complex that you seam to imply (+include some GIS background needs). But nothing is ever too late isn't it ? I'll come back later with examples as a graphic is far easier to understand than fix font ASCII art As a starting point for the shorter definition of what validity is, I suggest referring to the OGC standard this way : ''' A multipolygon relation in OSM is considered valid if it can be used, without discarding nodes or ways or part of ways to build a valid geometry as define by the OGC Simple Feature standard (http://www.opengeospatial.org/standards/sfs) with the notable exception of touching inner rings (see below). ''' -- sly (sylvain letuffe) _______________________________________________ dev mailing list dev@openstreetmap.org http://lists.openstreetmap.org/listinfo/dev
