I use the subarea member because it makes cross-checking easy. Have all the lower-level boundaries in my higher-level admin area been added to OSM?
Unfortunately the various admin levels do not always form a strict hierarchy. A small area at (lets say) admin_level=10 might be enclosed spatially by entities at level 8, 7, 6, 5 etc but it only has a direct administrative relationship with one of them, which might not be the next-highest level (next-lower number). Finding the boundaries of all districts within a county (UK example) becomes trivial with the explicit parent-child link. Otherwise its like finding all boundaries with admin_level=8 which are at least 99% contained by the higher-level boundary. That sounds computationally a lot more complicated to me. Why not 100%? Because sometimes the boundaries at different levels are not imported/drawn from the same source, leading to the boundaries not being exactly coincident. So there needs to be some tolerance in there. //colin On 2015-11-26 19:51, Martin Koppenhoefer wrote: > I just noticed that a lot of boundary relations have the lower ranking parts > included as members with the "subarea" role. This role is documented here: > http://wiki.openstreetmap.org/wiki/Relation:boundary > > But I wonder how it got on this definition page. Was this discussed anywhere? > I don't think it's a good idea to add all those lower entities in nested > relations (they are already spatially structured, this is redundant and makes > the relations more complicated for no good reason). > > I propose to remove this property from the definition page and move it to the > talk page. > > Comments? > Cheers, Martin > > _______________________________________________ > Tagging mailing list > [email protected] > https://lists.openstreetmap.org/listinfo/tagging
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