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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