[Talk-us] An admin_level for CDPs?

Richard Welty rwelty at averillpark.net
Mon Dec 31 21:22:39 GMT 2012


funny you should bring this up, i've been pondering CDPs a bit lately 
and have come to very different conclusions from yours.

On 12/31/12 3:30 PM, stevea wrote:
> I have been pondering the use of the admin_level key in the USA, and 
> have come to the realization that while  values 2, 4, 6 and 8 are 
> correct for national, state, county and city boundaries 
> (respectively), it is more complicated than that. It is likely time to 
> end the pretending this oversimplification is sufficient.  It is not.
>
> A useful tool is http://www.itoworld.com/map/2#fullscreen which shows 
> admin_level boundaries from 2 to 11 (11 for Germany and Netherlands 
> only) in different colors.  Yes, it is true in the USA that for those 
> boundaries which are tagged correctly (all 50 states, many or even 
> most counties, some cities) we do see good boundaries and colors.
>
> However, there are boundary polygons in OSM which are an odd duck in 
> the USA:  a notable one is Census Designated Places (CDPs), which came 
> from the TIGER import.  These are a bit like cities in that they are 
> often a similar size and population of a town or rather small city.  
> But they are not strictly cities, in that they are derived from the 
> federal government (not "negotiated" with a state government like a 
> city which is or has incorporated) crafting them for statistical 
> purposes.  CDPs have no legal basis as incorporated cities do.  In 
> fact, many of the residents of these areas may not even be aware of 
> the boundaries of their own CDP.  However, CDPs are useful, as they 
> often give name and shape to a place or area which otherwise might not 
> have one, and frequently the CDP yields the only boundaries for doing so.
>
> In other words, CDPs (and others, see below) really are administrative 
> divisions in the USA, we just don't often think of them that way, and 
> so we don't (often) classify them into a hierarchy.  I do believe it 
> is proper and useful to do so, but of course we should strive to get 
> to as correct as a consensus/result as we can.
>
the only "real" function of CDPs, so far as i know, is to provide a 
boundary to scope counting heads by the Census bureau. i'm hesitant to 
grant full
admin boundary status to them. in particular, they don't always nest 
well within the NYS Town boundaries, and in general the town containing
the CDP supplies the government for the CDP. CDPs are mostly around 
hamlets here.

the import of CDPs around here used level 8, so i've used level 7 for 
the NYS town boundaries i've brought in (manual import, one town 
boundary at a time.)

in the Capital District of NY, the
>
> As a starting point, we can keep this discussion simple and decide 
> whether a CDP might rightly be assigned an admin_level of 5, as it is 
> both a federal and quasi-local entity which correctly "lands in the 
> middle" (below state but above county), or whether it might actually 
> be lower than a city (but implying subordinate to? -- doesn't seem 
> correct...) with an admin_level of 9.
if they were to remain an admin_boundary (a case which i don't think 
you've adequately made) 5 is way, way too high given what the CDPs look 
like around here.

richard




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