[Talk-us] County road network relations

[Andrew Cleveland]

On Sun, 2011-04-10 at 17:02 -0700, Alan Mintz wrote: 
> At 2011-04-10 16:28, Nathan Edgars II wrote:
> >On 4/10/2011 7:25 PM, Alan Mintz wrote:
> >>At 2011-04-10 14:00, Kristian M Zoerhoff wrote:
> >>>What's the consensus for county roads in the US?
> >>
> >>I don't know what the consensus is.
> >>
> >>County roads in California are of the form [A-Z][0-9][0-9]. I tag Orange
> >>County route S18 as:
> >>
> >>network="US:CA:Orange"
> >>+ ref="CR S18"
> >
> >How does this work with routes that cross county lines? California has a 
> >statewide numbering system, with the letter roughly representing the part 
> >of the state.
> 
> Yup - that is problematic. I think, when I marked Orange County S18 last 
> year, I didn't see any other county road tagging to go by. 
> http://www.cahighways.org/county.html shows that there are some occurrences 
> of this. I apparently expected to break them at the county lines, I guess, 
> so as to agree with signage. That is, Orange County S99 would be a 
> different route than San Diego S99. network="US:CA:Orange;US:CA:San Diego" 
> on the relation seems workable.
> 
>   It's almost like they defined super-groups of counties identified by 
> those letters. I'll have to crunch that table to see if that's the case so 
> we could have network=US:CA:S + ref="CR S18". Maybe add an is_in:county tag 
> to the individual segments to avoid losing that important info.
> 
> I realize this is kind of scattered. On my way out the door.
> 
> 
> --
> Alan Mintz <Alan_Mintz+OSM at Earthlink.net>
> 
> 
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Hi,

That's correct that the county routes are grouped into "zones" which
don't necessarily coincide with counties. There are nine zones (A, B, D,
E, G, J, N, R, S).

There are some county route relations here:
http://wiki.openstreetmap.org/wiki/California/State_Highway_Relations#County_Highways
though it's not set in stone obviously. I guess either US:CA:[zone] or
US:CA:CR as suggested would work.