[Talk-us] National Forest boundaries

[stevea]

I (momentarily?) recede from my "watching mode" in this thread to offer my agreement with Mike and to reiterate a slight disagreement with Bradley (or maybe to ask Bradley and especially the wider list here for clarification), as while it seems we get closer to a "more definitive" way to tag NF boundaries, this discussion doesn't seem close to having yielded a complete agreement (yet).  Nor even full understanding, at least on my part.

My agreement with Mike is noticing that (in California only), CPAD data for NFs are excellent quality; I believe OSM users in California should feel comfortable using them for NFs, as when I look at the "SuperUnit" version of CPAD's release of these (there are also "Unit" and "Holdings," a sort of "parcel-level") NFs invariably have a big, SINGLE outer polygon (and up to hundreds of inners).  I wrote wiki on how CPAD data might be best utilized in OSM, see https://wiki.osm.org/wiki/California/Using_CPAD_data .  However, I'm not exactly sure how the outer polygons found in NFs differ from either the "Congressional" boundary or the one Bradley says he would tag "boundary=administrative" (and I don't think we should tag it that, especially while excluding a specific value for admin_level), but I'm willing to listen to more discussion about what this "different from Congressional" boundary is and how the two differ.  Apologies if that isn't clear, I'm doing my best, but I remain unclear on some concepts here.

My slight disagreement with Bradley is as above:  I don't think we should put a "naked" (missing admin_level) boundary=administrative tag on these, it simply feels wrong to do that.  (I READ the point that these are "Congressionally designated" and that SEEMS administrative...but, hm...).  One major problem I have is that we're multiplying polygons (by two) here for a SINGLE national forest.  Isn't there a way we can keep all these data in a single relation?  Yes, inner can remain as the right role for inholdings, maybe outer is better placed on either "Congressional" or "the other one that is more on-the-ground", maybe we coin a third role ("congressional"?) for that one, allowing us to keep the "bigger, enclosing" polygons in a single multipolygon relation, which I think is an "OSM-sane" thing to do.

Summarizing, CPAD data for California:  very good.  Maybe even excellent, though I think some examination of the differences of NFs between the SuperUnit, Unit and Holdings flavors of CPAD data is a very good idea that somebody (a Californian OSM multipolygon and shapefile jockey who knows something about national forest structure) should take some time to examine.  Differences between "the two" kinds of "more outer" multipolygon boundaries of NFs?  Murky, well, remaining somewhat murky in my mind, at least how these should best logically be expressed by OSM relations.  The discussion is good, I simply reiterate my "I still don't quite understand all of this very well" here and now.  Brian seems to agree with me and I don't think I'm alone.  Let's keep the momentum rolling until more / most of this achieve that "a-ha" moment as to how OSM should best express NFs with multipolygons.

SteveA