Coalesce special route networks in legend

[1ec5]

The legend added in #632 has a “Route markers” section that lists special or “bannered” route networks separately from their parent route networks. In most cases, users wouldn’t consider the special routes to belong to a separate network and would find this presentation to be redundant.

Most American print maps omit the special routes entirely, but this project’s legend is intended to inform users who are less familiar with AASHTO route designations than the average American motorist. Some maps include an unobtrusive decoder ring for the abbreviations that appear in the banners:

To power a similar table, we’d first need to determine that a network value is a special route. One clue would be the modifiers property that banneredShield() adds to a shield definition object:

https://github.com/ZeLonewolf/openstreetmap-americana/blob/820a1fe4c206c60cb32a12ea9ff83cef4be94e49/src/js/shield_defs.js#L969-L972

However, there are some tricky cases where we’ve called banneredShield() to distinguish two shields in the same region that otherwise look identical because of how we’ve drastically simplified the shields.

[michaelblyons]

However, there are some tricky cases where we’ve called banneredShield() to distinguish two shields in the same region that otherwise look identical because of how we’ve drastically simplified the shields.

Do you have an example? I found these, but they have black-on-white TWP-annotated and white-on-green with no annotation. It's not difficult to find two different networks' identical shields without annotation banners, but I don't know where to look for banneredShield() ones.

[1ec5]

I found these, but they have black-on-white TWP-annotated and white-on-green with no annotation.

Yes, these are the ones I’m thinking of. They do call banneredShield().

[michaelblyons]

Yes, these are the ones I’m thinking of. They do call banneredShield().

Ah. My mistake. I was comparing US:OH:LOG:Union to US:OH:LOG:Pleasant instead of comparing it to US:OH:LOG.
So ideally, we'd want this?

	Text	(For)
235	Ohio state routes	US:OH
24	Logan County routes Annotations: TWP	US:OH:LOG, US:OH:LOG:Miami, US:OH:LOG:Union
33	"Logan County routes"? "Pleasant Township"? Both?	US:OH:LOG:Pleasant

I haven't managed to get a TWP road in frame with an otherwise identical other-county road, which could look like any of these:

	Text	(For)
33	Foo County routes	US:OH:FOO
TWP 24	Logan County routes	US:OH:LOG:Union
	Or
24	Logan County routes Annotations: TWP	US:OH:LOG:Union
	Or
TWP 24	Union Township routes	US:OH:LOG:Union

I did get a shot with a county road whose township matches a neighboring county's main style. 😅 Ohio, what have you done!?

[1ec5]

Actually I meant this as an example of where we wouldn’t want to do any coalescing. The idea is that we wouldn’t insist on the creation of separate Wikidata items for US:US:Truck, US:OH:Business, etc., because we can tell that they’re the same as US:US and US:OH, respectively, with the addition of a banner on top. This gets complicated because it would result in the “Logan County routes” entry saying “Abbreviations: TWP = Union”.

[michaelblyons]

That makes so much more sense. Thanks for your patience!