[Talk-us] Network tag Re: Highway Shield Rendering

[Chris Lawrence]

On Wed, Apr 4, 2012 at 1:47 PM, Phil! Gold <phil_g at pobox.com> wrote:
> * Craig Hinners <craig at hinnerspace.com> [2012-04-04 09:14 -0700]:
>> One of many examples: Maryland uses a unique green-on-white shield for
>> US Business routes, but those roads still get tagged as
>> "network=US:US:Business", not "network=US:US:Business:MD" or somesuch.
>
> It seems to me that network=US:US:Business:MD is the logical extension of
> a scheme that has US:US and US:US:Business.  I had actually planned on
> attaching Maryland's US Business shields to the US:US:Business:MD network
> once I made them, but I haven't gotten to those yet.

Personally (and you can take my thoughts here with a grain of salt) my
original thinking was (whether clearly communicated or not):

network=* should represent a broad "shield type," roughly
corresponding with the core sign design in question (which is largely
universal, in the sense that all numbered routes are part of some
network - N routes in France or Ireland, federal highways in Mexico,
whatever)

ref=* what varies on the shield itself between routes in the same
network (maybe the number/designation... maybe the number with a
suffix, like "bis" in several European countries).

modifier=* would represent MUTCD-type banners attached to the shield
(which are largely a North American thing - in retrospect I probably
should have just called it "banner") and/or weird stuff like Georgia's
CONN. that you need to distinguish but would look silly at the same
size as the ref.

That said it may be easier to combine modifiers/banners into the
network as subtypes.  Renderers can fallback to the longest
left-anchored substring they understand for weird things they don't
understand.  Whatever folks want to do (including modifier -> banner)
would be fine with me; it's not like there are thousands of relations
that would need to be changed to the consensus that emerges.

As far as non-AASHTO stuff like "US 70A" (which I'm pretty sure AASHTO
considers "Alternate US 70"), my gut feeling is to tag how it's signed
in the field even if it's not technically correct - e.g.
network=US:US, ref=70A - as long as we're talking about single-letter
suffixes.  I still haven't really thought through what to do about
Arkansas' irritating redundant signing style (Truck AR 7T), although
there again field signing (ref=7T, network=US:AR:Truck or ref=7T,
network=US:AR, modifier=Truck) is probably less likely to result in
data consumer confusion based on naive rendering than doing something
"technically correct" - presumably at some point AR 7 and Truck AR 7T
intersect, so you'd want the map or your GPS app to distinguish
clearly which one is which.


Chris