[Talk-us] Strange city boundary: Lee, Illinois

Kevin Kenny kevin.b.kenny at gmail.com
Wed Nov 14 16:26:16 UTC 2018

On Wed, Nov 14, 2018 at 11:07 AM Martijn van Exel <m at rtijn.org> wrote:

> Hmm.
> I guess https://wiki.openstreetmap.org/wiki/United_States_admin_level is
> really not correct then where it says: "Census Designated Places (CDPs) are
> boundaries maintained by the Census Bureau for statistical purposes. CDPs
> should be tagged boundary=census, ideally without an admin_level=* tag.”
> Almost all Utah admin8 are in fact TIGER CDP boundaries:
> http://overpass-turbo.eu/s/DFS
> Also,
> https://wiki.openstreetmap.org/wiki/Tag:boundary=administrative#10_admin_level_values_for_specific_countries is
> incorrect where it states that admin8 are "state municipalities: cities,
> towns, villages and hamlets (infrequent)”
> Furthermore,
> https://wiki.openstreetmap.org/wiki/WikiProject_United_States/Boundaries is
> also incorrect and suggests "Census-designated places (CDPs) are
> statistical, not administrative areas. Project TIGER fixup deletes outdated
> CDPs and retags relevant ones from boundary=administrative admin_level=8(or
> 7) to boundary=census, no admin_level=*.”
> Finally, there seem to be too many wiki pages covering this :) But that’s
> not unique for this topic.

CDP's do follow administrative boundaries for the most part, because many
states ask the census to respect administrative boundaries (depending on
census statistics for their own use).  Where stuff is really untrustworthy
is where the Census Bureau had to invent the lines because a designated
place was unincorporated.

That's actually pretty common. New York has a couple of densely populated
"hamlets" with populations of over 50000 that never voted to adopt a city
charter and so have no municipal government other than the township. Some
of them even have official boundaries, generally because they are
completely surrounded by incorporated communities, but sometimes as part of
the town's bylaws.

There are, nevertheless, a number of cases where the Census Bureau goofed.
The neighbourhood where I grew up is one - for years the Census and the
Post Office both placed it inside New York City, but it is not. The
confusion was caused by the fact that the Post Office found it most
convenient to sort the mail at an office in a neighbouring community that
is in New York City, so the neighbourhood had a New York City ZIP code
despite being in adjoining Nassau County. Residents found themselves in
court, often, for failure to pay the New York City income tax that they did
not owe, and so on. The city line is more or less correct in OSM, by the
way, and I *think* that the Census Bureau had redrawn the CDP by the time
TIGER was created.

(Lesson: ZIP codes do not designate administrative regions. In fact, they
do not necessarily designate contiguous geographic regions, or in fact, any
geography at all. They are nothing more nor less than sets of mailboxes
that the Post Office finds it convenient to sort together.)

Also, TIGER. Enough said about TIGER.  Please clean the cat box any time
that you get a chance.
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