Concerning ref tags on ways, I don't think there's a need to impose nationwide "consistency". I also don't think it's worth even adhering to a strict machine-parseable syntax (particularly dealing with overlaps) since that kind of information is much better organized in relations.
That said, here are my "ideal" guidelines for formatting ref tags on single state highways: 1) If there is one clearly-popular abbreviation, such as M-xx in Michigan or possibly K-xx in Kansas, use it. 2) If a state has primary and secondary state routes, or numerous classes of state routes like Texas, the prefix should indicate the route class. 3) If a state allows its state routes to have the same number as a US or Interstate route in that state, a state-specific prefix (postal abbreviation or other as described above) should be used. 4) If a state is large (such that most places aren't "near" the borders) a generic prefix like SR or SH or STH (depending on preferred local terminology) may be used, notwithstanding guideline 3. 5) If a state's state route markers are generic (circle/oval or box) and don't specifically identify the state, a generic prefix or no prefix may be used, notwithstanding guideline 3. 6) Consistency within a state, or within broad regions of larger states, is probably still of value. A format should be chosen by consensus of mappers familiar with the state or region in question. 6a) As a mapper familiar with Ohio, I prefer SR xx, but would be amenable to OH xx or OH-xx. Slightly off-topic: A) I strongly prefer I-xx and not I xx (and definitely not Ixx) for Interstates. The hyphen enhances readability and reduces the chance of the I being mistaken for a 1. The reasons I've heard in support of I xx are: to match US and state routes (why does it have to?); to match European route designations (making apples look like oranges); because "all" the Interstates are already tagged as I xx (due to a few editors who value consistency a little too highly, plus I see that as a circular argument); changing it breaks renderers (nearly all renderers just pass a way's ref tag directly to the output, and those that do try to parse it can and should normalize tagging variations as a preprocessing step anyway). On the other hand, I would't argue against the format IH xx in Texas because most Texans I've encountered write it that way. B) When routes overlap, there is no "right" way to format the way's ref tag. I don't think any active renderers attempt to separate it into multiple values; considering this information can be stored with much better structure in relations, I don't think any programmer wants to bother with trying to parse a ref string anyway. That just leaves humans who will ever read it, and we can optimize for that. Brevity may be more important than technical correctness when a human is reading. Local understanding of routes' relative importance may play a role. The following "equations" demonstrate options to represent overlapping routes in a way's ref tag that seem perfectly sensible to me: US 1 + US 9 = US 1-9 I-70 + I-71 = I-70/71 US 40 + US 62 + OH 16 = US 40-62 I-74 + I-465 + (?) = I-465 I-95 + MA 128 = I-95/128 US 68 + OH 15 = OH 15 These little white lies are close enough to match the line on the map to the road on the planet. (Every good map has to lie in some way to convey information effectively.) If someone really wants to know which routes follow a particular way, they should examine the relation(s) that contain it. If a mapper really wants to make sure the correct, official truth is represented in the database, they should make sure all relevant route relations exist and are correct. Trying to squeeze all that information into a single string with a rigid syntax is optimizing for a use case that essentially doesn't exist. On Sep 12, 2012 8:59 PM, "Charlotte Wolter" <techl...@techlady.com> wrote: > Hello all, > > ** **Was there ever consensus on whether to use "SR" (or some > variation on that) for state highways versus an abbreviation of the state > name ("CA" or "NY"). I remember that there was discussion, but I don't > remember if there was consensus. > ** **Thanks. > > Charlotte > > ** > > ** Charlotte Wolter > 927 18th Street Suite A > Santa Monica, California > 90403 > +1-310-597-4040 > techl...@techlady.com > Skype: thetechlady > > *The Four Internet Freedoms* > Freedom to visit any site on the Internet > Freedom to access any content or service that is not illegal > Freedom to attach any device that does not interfere with the network > Freedom to know all the terms of a service, particularly any that would > affect the first three freedoms. > > _______________________________________________ > Talk-us mailing list > Talk-us@openstreetmap.org > http://lists.openstreetmap.org/listinfo/talk-us > >
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