[Talk-us] State highway refs (was Re: New I.D Feature)

stevea steveaOSM at softworkers.com
Sun Nov 30 18:41:22 UTC 2014

>On 2014-11-29 22:45, Shawn K. Quinn wrote:
>>On Sat, 2014-11-29 at 22:21 -0800, Minh Nguyen wrote:
>>>Do any routing engines currently care about prefixes on way refs?
>>>   From what I've seen so far, most of the map styles that use the ref tag
>>>to distinguish route networks will recognize either the state
>>>abbreviation, "SR", or "SH". Some renderers use the prefix to choose a
>>>state-specific shield, assuming any unrecognized prefix is for a county
>>>route (white rectangle at higher zoom levels). MapQuest only recognizes
>>>state/provincial abbreviations. Not that we should place too much stock
>>>in individual renderer decisions. :-)

My two cents:  I must say that here in California, I've made it a 
habit to remove the "County Route" designation (CR) which precedes a 
ref number in our County Route system.  For example, NE2 (a 
banned-from-OSM former contributor for those unfamiliar with that 
history) entered ref tags for many G2, N1... county routes as "CR G2" 
and "CR N1."  That, in my opinion, is so redundant (as G and N and A 
and S... are well-known multi-county/regional-within-California 
county highway networks) as to be true clutter.  People in California 
do know (and routing software, renderers... SHOULD know) that A1, G2, 
N4 and S16 are county routes in a lettered system where each letter 
represents a cluster of counties...at least in California.

Also, while "SR" (for "State Route" in California and other states) 
is still legally correct, I still might change for consistency's sake 
any "SR" prefix I see in a highway route relation ref tag to be "CA" 
instead.  So, while "SR 17" is correct, I much prefer "CA 17" and 
will change it to that if I see SR in a California highway route 
relation ref tag.

I agree with what we (as OSM volunteers entering/editing data in our 
map) now do, as well as what map styles/renderers and routing engines 
do, as Minh notes above:  "recognize the state abbreviation, SR or 
SH."  Yes, Michigan still has its M- routes, and I think OSM (both 
its human editors and software components) should just learn to cope 
with that (plus perhaps a few other states) as exceptions to this 
largely (though not completely) applicable rule.  I believe we are 
pretty much there, but we still have edge cases, data in the map and 
newer contributors who are not completely familiar with these 
conventions in the USA.  Discussing it here helps, though wiki 
documentation and taginfo data which are consistent across the fifty 
states is better.


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