Ok, it's reassuring that I'm not totally off in the weeds. Private inholdings in the state lands are more the rule than the exception in the Adirondacks, so I expect to have a great many untagged inner rings.
I don't expect to cut out lakes. Since the idea is to tag the areas with boundary=protected_area, and the protection extends to the waterways, the tagging should as well. To do otherwise in order to make the map prettier would be tagging for the renderer. One exception is that the NYSDEC database includes parcels that are entirely under water. I propose to ignore those at present. Another detail: There are several places where the parcel lines appear to align with watercourses. In some cases the forest and the waterway share ways. I propose to separate them. If a stream changes course, a lake dewaters, or the beavers flood another few hundred acres, the property lines ordinarily do not move. Since I'm displacing property lines a couple of meters inward to reduce GPS noise, the separation should be clean. On Jun 21, 2016 10:10 AM, "Eric Ladner" <eric.lad...@gmail.com> wrote: > On Mon, Jun 20, 2016 at 8:08 PM Kevin Kenny <kevin.b.kenny+...@gmail.com> > wrote: > >> The only way that I can see the current tagging working is if there >> is some hidden coupling where it is understood that tags that apply >> to an outer way of a multipolygon relation actually belong to the relation >> itself, and the inner ways are excluded implicitly. If so, that puzzles >> me, >> because that's also not what I see the renderer assuming. >> >> Can someone please explain to me how I should be tagging things >> so that the polygon-with-a-hole becomes a protected area? The ones I did >> in the Catskills, like https://www.openstreetmap.org/relation/6304902 >> appear to render as I intended, but I know that there is lots of nonsense >> tagging that still renders prettily. >> >> Kevin >> > > I think your perception of how multi-polygons work is correct. Tagging > should be at the multipolygon level. E.g. if it's a park split by a road > maybe, both ways are members of the multipolygon, and the relation is > tagged with "type=multipolygon; leisure=park" and both ways with > "role=outer". Maybe if there was something in the middle of the park, it'd > have a ring, that was tagged with nothing, but has "role=inner" on the > relation. But, if it was a substation or lake or something, you could tag > the inner ring with natural=water or power=substation. > > Granted, if you tagged the outer ways directly and left the relation with > nothing but "type=multipolygon" it would still render correctly, but it's > not the correct way to convey information. Just because it looks pretty > on the map doesn't mean it's right. > > JOSM flags this condition (tagging on outer ways instead of the MP itself) > as a warning when you're uploading. That's probably a good indication it's > not a good practice. > > Think of it from a data maintenance point of view. If you have some huge > national park with 30 outer rings, do you want to manage 30 separate sets > of information on each outer way, or one set of information on the > multipolygon relation they all belong to anyway? > > Eric >
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