[Talk-us] admin level for US states

Minh Nguyen minh at nguyen.cincinnati.oh.us
Tue Nov 25 10:24:40 UTC 2014

On 2014-11-25 01:29, Martin Koppenhoefer wrote:
> 2014-11-24 21:18 GMT+01:00 Minh Nguyen
> <minh at nguyen.cincinnati.oh.us
> <mailto:minh at nguyen.cincinnati.oh.us>>:
>     Assuming this table reflects the actual state of the map, most
>     countries have chosen 4 for their state equivalents.
> Actually, many countries do not have something like a "state
> equivalent", it is a particularity of the USA because they are a federal
> republic.

I understand; I just meant that most countries have chosen admin_level=4 
for the second-level governmental authority, regardless of any autonomy 
or sovereignty. That is, most of the level 3 entries in the table are 
for entities that have no legislative or executive function. I don't 
think it was historically viewed as a problem that admin_level=4s in 
different countries had varying levels of autonomy.

>     This level-skipping scheme extends all the way down to the smallest
>     jurisdictions. Because the TIGERcnl import chose admin_level=8 for
>     municipalities, skipping 7, I was able to tag Ohio townships as 7
>     without demoting all the state's cities and villages. [2] Even
>     though neighboring Kentucky and West Virginia lack a level of
>     government between counties and municipalities, it makes sense to
>     keep cities in most states at the same admin_level, because they're
>     functionally equivalent. (Virginia is a notable exception.)
> I was not going to get into discussion about cities and other lower
> level admin entities. Please lets stick to the state question.

My point is that there's a pattern. Using 4 for states is not an 
arbitrary choice, but rather an intentional way of leaving room for 
additional detail.

Incidentally, [1] is silent on the question of Indian reservations, a 
topic that has come up periodically on this list. Is there any consensus 
on how to tag them? If so, it should be reflected in the table.

>     For context, there's an open pull request to have the Standard
>     stylesheet render country and state labels based on administrative
>     boundary polygons rather than place nodes. [3]
> yes, this is also something I wanted to point to, because in the
> discussion for this style change it was argued that some countries,
> which currently do use level 3, should change that to level 4 (like the
> US), and I was arguing the other way round, that the US should probably
> change the states to level 3 instead.

It sounds like the intention is to preserve U.S. state labels at z4 (by 
promoting them to level 3) while demoting subdivisions of smaller 
countries to higher zoom levels (by keeping them at level 4). I'm all 
for a more readable map of Europe, but basing admin_levels on degrees of 
autonomy won't really solve the problem. Some federal republics have 
relatively small second-level divisions (e.g., Switzerland), while some 
very large second-level divisions happen to be provinces of Canada, 
which is not a federal republic.

>     Martin, how would the U.S. would be affected by this change? As it
>     stands, U.S. state boundaries and labels appear at z4 and above,
>     regardless of the state's size. Of the smallest states, Rhode Island
>     (RI) appears at z4 and z6+, Connecticut (CT) appears at z4+, and
>     Maryland (MD) and Delaware (DE) are both obscured at z4 by the label
>     for Washington, D.C.
>     At a glance, this change would seemingly omit most of the
>     Northeastern states' labels at z4.
>     It appears to set a minimum size of 750 "way pixels" at z4 and 3,000
>     at z5 for displaying a state's label. I don't really see those
>     states' two-letter refs as being clutter.
> I am not sure why raising the importance would lead to less names
> displayed. If this holds true, the stylesheet would have to adopt to
> correct this IMHO.

Sorry, I should've been clearer. It seemed to me like the proposed 
stylesheet change would cause some labels to disappear at z4-5 without 
any changes to the data, because the stylesheet would enforce a minimum 
area, whereas currently it doesn't. But I haven't tried out the change, 
so hopefully I'm wrong and the U.S. will look good either way. :-)

[1] http://wiki.osm.org/wiki/United_States_admin_level

minh at nguyen.cincinnati.oh.us

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