[Talk-us] An admin_level for CDPs?

stevea steveaOSM at softworkers.com
Tue Jan 1 22:18:11 GMT 2013

>On 12/31/12 5:12 PM, Minh Nguyen wrote:
>>I'd argue that not all governmental boundaries need to be tagged as 
>>boundary=administrative. In Ohio, we've started to retag CDP 
>>boundaries with boundary=census and place=locality but without 
>>admin_level. [1][2] They still show up in Nominatim as localities.
>this is approximately what i was thinking should be done with CDPs.

This sounds workable to me, as well.  It is agreeable that CDPs not 
have an assigned admin_level, I was opening this for discussion to 
see if there might be wider consensus.  CDPs *are* created by the 
Bureau of the Census, but the *SAs are not, they are created by the 
Office of Management and Budget (OMB).

It *does* beg the question of what *should* be tagged as 
boundary=administrative *and* have an admin_level tag.  For example, 
my local University of California campus has a polygon tagged 
boundary=administrative, border_type=university (and 
amenity=university + name=*).  Might/should it also be tagged 
admin_level=4?  Even though it partially overlaps (and largely is in) 
City Limits, it *is* an administrative unit of state government 
(neither city/local nor county) with its own police, fire and 
health-care infrastructure, its own planning and development 
functions and a recent lawsuit (since dismissed) between it and its 
"host" city, proving it and the city are different entities.

The same question (admin_level=4) might also be asked about 
California State Park boundaries...but they are *already* tagged with 
admin_level=4, so at least there is precedent (thanks, Apo42) for 
state-level "units" with specific administrative boundaries to be 
tagged with admin_level.  I'd like that to become widespread among 
all 50 states, which also implies national parks get tagged with 
admin_level=2.  State/national parks and state universities really do 
have their own administrations, and this implies an admin_level tag.

>>In states that give civil townships some authority, they are much 
>>more important to the identity of an unincorporated area than CDPs. 
>>The TIGER boundary import excluded Ohio townships, so Vid the Kid 
>>and I have been painstakinglly filling them in.
>i have started filling in Towns in upstate NY as well. i don't mind 
>identifying the Hamlets in some manner, but all they consist of 
>typically is a boundary drawn by the Census, and some 
>green-and-white signs posted by the NYS DOT in traditional locations 
>by the road side. there's no government there, whereas the towns 
>maintain roads, provide the framework for the volunteer fire 
>districts, have a zoning & master plan functions, inspect buildings 
>& construction, and so forth.

What I found useful to do around here (where there are CDP polygons 
entered from TIGER, but they have no admin_level tag) is to add a 
point tagged hamlet=* or village=* or town=* (but not necessarily 
suburb=* as that implies city subordination, nor city=* as that 
implies incorporation) to the "approximate center point" of the CDP 
polygon, along with a name=* tag that matches the name of the CDP. 
This point might logically be a mathematical centroid, but I have 
found it more useful to place this point at a more culturally 
significant point in the "human center" of the community designated 
by the CDP.  Usually this is at or near a significant crossroads, 
where there might be a market, a church, a school, a small commercial 
district, or the like.

What I am hearing:  there are many polygons in OSM with the tag 
boundary=administrative, but it makes sense for only some of them to 
have an admin_level tag.  (This seems odd, but gets solved in the 
case of CDPs having their boundary=administrative tag changed to 
boundary=census).  We agree on nation, state, county and city (2, 4, 
6, 8), but there really are other polygons upon which we might 
appropriately add an admin_level tag, state parks being one of them. 
CDPs, no, but changing their tag from boundary=administrative to 
boundary=census seems a good idea.  And for other *SAs designated by 
the OMB (not the Bureau of the Census)?  What about those?

Finally, while there seems to be no argument that New York City is 5, 
and LAFCos in California are 7, what about MPOs?  These are a odd 
blend of where a locality's transportation planning agency wants to 
qualify for federal money, so they create an MPO per federal Code 
which qualifies them for it.  This MPO becomes a de facto and de jure 
administrative boundary, for both local and federal reasons, 
effectively bypassing state-level government.  Do we want to assign 
MPOs an admin_level tag in OSM?  (I'm guessing no, but I feel the 
need to offer due diligence that at least this question was asked).


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