From the USFS data mentioned earlier, I noticed two oddities that did not jibe with my understandings. #1, when there is an overlap of boundaries between federal and state land, the two cannot be coincident (i.e. EITHER National Forest OR State Park must be the owner of the overlapped land). #2, I thought Wilderness boundaries were always a "subset" of a "parent" National Forest.

I wrote and asked, and got a prompt reply from Troy Warburton, ALP Deputy Program Manager, USFS:

Troy-Both Forest Service and Park Service lands, excluding any pre-existing rights, are considered to be public lands owned by the United States. The difference is administrative responsibilities. Areas within a National Forest Boundary may have additional restrictions, such as a National Park, National Monument, National Scenic Area etc..

Troy-A determination would have to be made on a case by case basis as to whether the boundaries in question are meant to be coincident but the Forest Service is currently in the process of reviewing and updating all LSRS data to insure boundaries that should be coincident are vertically integrated with other pertinent data sets. As LSRS data is updated it will be made available through the FSGeodata Clearinghouse web site.

So, for #1, Federal lands can overlap other federal lands, though a particular distinction might have certain restrictions compared to another. OK, my head wraps around that, and OSM accommodates that (e.g. a polygon tagged leisure=nature_reserve for Wilderness inside of a polygon with landuse=forest for National Forest). Troy says Parks, Forests, Monuments, Scenic Areas can "blur together" like this, but the idea is the same for Wildernesses, as OSM tags are different to accommodate those. OSM is on board: so far, so good.

Additionally, Troy says there will be updates to these data to harmonize overlapping boundaries with OTHER (non-federal) jurisdictions, like states. An example (the one I gave him) is how Limekiln State Park (California) seems to "intrude" upon what the USFS says is Los Padres National Forest. I think what will happen is USFS will eventually get around to noticing this (these, really), "carve out from" its boundary for LPNF where Limekiln is, and then re-publish its data. When somebody like me importing these data into OSM notices fresher data, I or another person will have to update, just like any OSM data which change over time. In the meantime, OSM may display these errors in USFS's data by overlapping with other jurisdictions. Yep, even the federal government admits it makes mistakes in data it publishes, then asks for more time to "vertically integrate" other data sources. OK.

Troy-Wilderness boundaries can extend beyond a National Forest boundary on public lands administered by another agency.

OK, I didn't know this. But whether one, the other, or both simultaneously, each are federal land, even if administered by different agencies (e.g. Department of Agriculture/Forest Service OR Department of Interior/National Park Service). There are also STATE Wildernesses, for example, Anza Borrego Desert State Wilderness. Again, OSM does accommodate both overlapping boundaries and their administrative differences via tags. These semantic distinctions render on mapnik as what we might call "mostly pleasing." For example, both boundary=national_park + ownership=national tags are on USFS wilderness boundaries, but not on State Wilderness boundaries, which (should, but often don't) get the tag ownership=state.

However, the tag boundary=national_park is confused, as it is widely overused, especially on STATE parks. Arguments are valid either way whether to include or exclude it on State Parks. The reason appears to be that boundary=national_park is mapnik-rendered as a pleasing dashed green line, and name text appears at wide zoom levels (up to z=6). Hence, the "overloading" of it on "non-national parks" so it renders anyway.

While we could quibble about whether "the fifty states are sovereign..." (they are) and so this means it is OK for state parks to have boundary=national_park tags, OR, boundary=national_park should be solely reserved for National Park Service "National Parks" (in the USA, anyway), I'd rather not. A better discussion might be where as a first step we posit a new mapnik rendering rule: boundary=state_park renders just as boundary=national_park, except with dashed blue lines, instead of green. In a new thread, please.

Oh, four National Forests -- Los Padres, Angeles, San Bernardino and Cleveland -- and all of "their" thirty or so Wildernesses are now in OSM using these fresh USFS data. I have updated the wiki accordingly.

Thanks for reading. Wiki pages seem too low-audience for these topics, talk-us seems both more-eyeballs and to the right geographic distribution.

SteveA
California
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