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

Carl Anderson carl.anderson at vadose.org
Wed Nov 14 16:27:34 UTC 2018


Don't let the prior import of tiger places lead you ignore that dataset.

Did you know that you can use the LSAD field in the TIGER place files to
distinguish between
legally incorporated entities such as Cities, Towns, Villages, and CDPs?

Did you know that the U.S. Census Bureau maintains the (USGovt)
authoritative boundaries for cities and incorporated government entities.
This does not mean that what they have is perfect but it means that all of
the US Govt uses the Census boundaries for grants, emergency aid,
population counts and other things.

It is done through the annual Boundary and Annexation Survey (BAS).

Some select LSAD codes
    25 -- incorporated City
    43 -- incorporated Town
    47 -- incorporated Village
    57 -- CDP (not a legal entity, for statistical use only)


On Wed, Nov 14, 2018 at 11:08 AM Ian Dees <ian.dees at gmail.com> wrote:

> Nope, I'm saying all those wiki pages are correct. CDPs are boundaries for
> statistical purposes, not city boundaries.
> But I agree there are too many wiki pages :).
> On Wed, Nov 14, 2018 at 10:04 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 Project TIGER fixup deletes outdated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.
>> I guess we have some work to do!
>> Martijn
>> On Nov 14, 2018, at 8:54 AM, Ian Dees <ian.dees at gmail.com> wrote:
>> A friendly reminder that Census's TIGER data we have previously imported
>> as admin8 polygons aren't actually official city boundaries. They're "Census
>> Designated Places <https://en.wikipedia.org/wiki/Census-designated_place>"
>> which are just named "concentrations of people". In some cases the Census
>> may have gone to the trouble of incorporating city boundary information,
>> but my guess is that the majority of cases are just "Census blocks that
>> look like they're part of the city".
>> Having said that, there really isn't a good national-level dataset of
>> city boundaries and Google uses CDP boundaries for their search results...
>> On Wed, Nov 14, 2018 at 9:49 AM Martijn van Exel <m at rtijn.org> wrote:
>>> Sorry that link is bad. https://cloud.rtijn.org/s/ZLen9D8M3tYaAgj
>>> On Nov 14, 2018, at 8:44 AM, Martijn van Exel <m at rtijn.org> wrote:
>>> I looked at a few place boundaries in Utah and compared with current
>>> TIGER files.. Definitely needs work..
>>> https://www.dropbox.com/s/e1113me8y9t1my5/Screenshot%202018-11-14%2008.42.30.png?dl=0 (colored
>>> = current OSM, grey = TIGER places shape file 2018)
>>> Martijn
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