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

Ian Dees ian.dees at gmail.com
Wed Nov 14 16:08:11 UTC 2018


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 Project TIGER fixup deletes outdated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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