[Talk-us] Differences with USA admin_level tagging

[OSM Volunteer stevea]

Kind of long and complex ahead; apologies in advance for the length.

I've been documenting our https://wiki.openstreetmap.org/wiki/United_States_admin_level wiki over much of the last year with careful research on how US states and territories carve themselves up into administrative subdivisions.  My thrust has been how states actually do this via their state constitutions, state legislation, real-world practice and in some cases on-the-ground signage (e.g. city limit or township boundary signs).  Research indicates minor differences in the way that the US Census bureau does something quite similar, and as noted in that wiki, OSM largely aligns, but there are minor exceptions (e.g. census boundaries in Alaska may be valuable enough to keep, but let's not call them administrative boundaries, they are not, but it's OK if the Census Bureau does so if we note that minor difference and tag in a way we discuss and document).

Whether those results (that wiki and its necessarily complex table and Notes) are fortunate or unfortunate, this prompted another OSM mapper (Minh Nguyen, he has kindly given me implicit permission to name him and explicit permission to cite his recent WikiProject addition) to create "his" https://wiki.openstreetmap.org/wiki/WikiProject_United_States/Boundaries wiki.  Minh's thrust there has been to carefully document what admin_level tags OSM actually DOES HAVE.  Even if those tags are "incorrect" in some legal sense, he documents what actually IS in the map.  OK, fine:  that is a noble goal and he has largely achieved it with this wiki in short order.

Without going through the sausage-making details of the flurry of our recent dialog (in wiki, talk-pages and private email exchanges), I am taking Minh up on his offer to "propose a change on the mailing list. Rally the OSM community behind your cause. You can even hold up the WikiProject United States/Boundaries page as a testament to how incorrect the map is right now."  (I quote Minh exactly there).  By doing so, I hope to generate more light than heat, essentially harmonizing both of our efforts and as a result, significantly improving our map.  Perhaps along the way, we hopefully better clarify what we mean by consensus:  what "the People" say via law and practice and what "we actually do in OSM as we put data into our map."  These are not and should not be fundamentally disharmonious, but the distinction seems to have created some friction I'd like to "solve."

Briefly (re-)stated, Minh characterizes this dichotomy as "prescriptive vs. descriptive."  In other words, Minh and I both claim the US_admin_level wiki prescribes how we SHOULD tag admin_level in the USA and the US/Boundaries wiki describes how OSM now DOES map them.  Our dialog has allowed me to identify specific differences, what appear to be deficiencies in our map, actually.  These are limited to nine US states (eight with deficiencies, a ninth with what appears to be a deficiency and perhaps an "off-by-one" error).  I now list these issues.

Here are what exist in state constitutions/statutes/the real world, map well onto OSM's admin_level scheme, yet do not exist in OSM's data:

Rhode Island 7/Town, 9/Village:  all are marked as 8/City when perhaps some are 7/Town or 9/Village
Massachusetts 7/Town:  all are marked as 8/City when perhaps some are 7/Town
Maine 6/Unorganized territory and 6/(unincorporated) Plantation
Vermont 8/Village:  all are marked as 8/City when perhaps there are 9/Villages in some 8/Cities
Pennsylvania 7/Township, 7/Borough are missing throughout, 8/Town subordinates to Borough, 8/Village and 8/Hamlet both subordinate to 7/Township
Connecticut 6/Region (not County), or both?  Harmonize these
Minnesota 7/Township, 7/Town (it appears simply that none have been entered)
Illinois 7/Township, 7/Precinct?

New Hampshire, 8/Town:  shouldn't these be 7/Town (as inTownship)?  Are there 7/Organized Locations?

To read this, then perhaps participate in first discussion, then possibly "solve" these issues, take the second line (Massachusetts) as an example.  Massachusetts did the MassGIS import, which included "City" boundaries and set their admin_level values to 8.  However, I assert (politely) that Massachusetts also has "Town" boundaries (sometimes called "Township" and by consensus yielding an admin_level value of 7) which either are or aren't in OSM (I can't tell) and which should have their admin_level set to 7.  But it appears they do not.  Again, OSM seems to need to identify "which, whether and how" we do this, on a state-by-state basis, in identifiably (only) nine US states.  I have taken it about as far as I can go, Minh has does yeoman work, we now have a "diff list" and now I post to talk-us to help us better untangle.  Can YOU "take a state or two" and help?

I suggest that we keep discussion of this to a minimum on talk-us (though we can by replying to this thread) and that the gory details be (largely?) dumped into https://wiki.openstreetmap.org/wiki/Talk:United_States_admin_level#Nine_state_improvement

Truly, I wish light, not heat.  And I believe our map in the US should, can and will improve because of these efforts.  Thank you for any participation you can muster or offer.

Steve All
Santa Cruz, California