[Talk-us] Scrubbing route relations

Michal Migurski mike at stamen.com
Mon Oct 22 04:54:40 BST 2012

On Oct 21, 2012, at 5:28 AM, Minh Nguyen wrote:

> On 2012-10-20 4:00 PM, Michal Migurski wrote:
>> 	- Normalizing network names for all county routes with the ":CR" infix
> I'm not enthusiastic about sticking `:CR` in all the county route relations. I favor `US:[state]:[county]`, at least for the relations in Ohio, for the same reason we have `US:[state]` rather than `US:SR:[state]`. It doesn't look like you touched any Ohio county routes, but that's probably because you didn't realize that's what they are. :-)
> Ohio county route relations' `network`s conform to a simple pattern: `US:OH:[ABC]`, where [ABC] is the county's three-letter, all-caps ODOT code. Obviously, the codes aren't used as commonly as USPS state abbreviations, but many counties use them on signage, and they're quite handy for this purpose.

That's right, I didn't understand those and they didn't look like county names, so I left them alone. The nice thing about the ":CR" part is that it helps explain what the word is after, for example county names. There are only 50 states so it seems easier to just say "US:[state]", but there are loads more counties and it's impractical to remember them all on sight.

> Having the extra `:CR` component might make sense in states like New Jersey and California that have consistent, statewide county route standards. But in Ohio, most counties that signpost their routes do it in different ways, in violation of the state MUTCD. There are so many variations that entire websites [1] are devoted to documenting them. (And as you'd imagine, some townships have their own unique route shields, too.)

That's interesting and worth knowing, thanks.

> You mentioned that using `:CR` makes it possible to "correctly interpret" county routes without knowing the county names. I guess that depends on what we expect the relations to be used for. To a developer generating shields for display on a map, `:CR` would suggest standardizing on, say, the blue and gold pentagonal shield, when in fact that would be misleading in maybe three-quarters of the state. And I'd say the shields are the /only/ interesting thing about Ohio county routes.
> By the way, if anyone's interested in rendering these shields, I've started a collection of SVG templates at Wikimedia Commons [2]. One thing I learned while making these templates is that some counties include the township name in their county route shields. Presumably, a route that crosses township lines would have more than one shield variant. Should we have subrelations with the township name in `modifier`?

The blue and gold shields are used in many places around the country, right? I think you're right, that using ":CR" where those are in place would make a lot of sense.

I feel like this scrubbing process has revealed so much about the intricacies of different road networks that I'm going to take a slightly different approach, and focus my work on just the ref and modifier tags. I can standardize the US:US and US:I networks along with US:CA where I live, but I should hold off on attempting to overfit other states' network tags.


michal migurski- mike at stamen.com

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