Use legacy shields for state routes in the United States

[1ec5]

As of #5145 #5310, the maneuver banner and road name label are using a new set of Mapbox-designed shields. This new set of shield assets regresses the behavior for state routes in the United States. Each state has a very distinct design for its state route shields, but the state-specific shields were omitted due to size and resource limitations. Users still need to see accurate shields to avoid making the wrong decision at highly trafficked interchanges throughout the country.

Until Mapbox-designed state route shields are available, we should use the legacy shields from Wikimedia Commons for state routes. Whenever mapbox_shield.name is us-state circle-white, use imageBaseURL instead of mapbox_shield.base_url, and append the .png or .svg file extension as desired. (If I’m not mistaken, navigation-native exposes imageBaseURL as well.) Regardless of file format, the legacy endpoint always bakes the number right into the image, so no compositing is required, but the image can’t be reused for other routes within the same network. The SVG files are not as optimized as the new SVG files and may not conform to the subset of SVG that can be converted to vector drawables. I think it would be acceptable to use the PNG files for this fallback to avoid any uncertainty about SVG conversion.

/cc @abhishek1508 @jill-cardamon @ShanMa1991 @ClareTrainor

[abhishek1508]

In this case how do we address the request from customers that the shields in maneuvers should match the shields on the Map, since as far as I know Map continues to use generic mapbox designed shields.

• Does this behavior in this case needs to be configurable?
• Is this behavior only applicable to US since wikimedia shields probably are not available for other countries?

cc @1ec5

[1ec5]

In this case how do we address the request from customers that the shields in maneuvers should match the shields on the Map, since as far as I know Map continues to use generic mapbox designed shields.

The requirement was for consistency in general, but this is a special case where consistency with the map would come at the expense of usability and amount to a regression compared to earlier versions.

Is this behavior only applicable to US since wikimedia shields probably are not available for other countries?

This is only applicable to the us-state shield type, which only occurs in the United States. Shield coverage is an open-ended endeavor, but all we’re currently regressing is state routes in the U.S., because the previous system only covered the U.S.

[1ec5]

This was implemented on iOS in mapbox/mapbox-navigation-ios#3723.

[1ec5]

Whenever mapbox_shield.name is us-state, use imageBaseURL instead of mapbox_shield.base_url, and append the .png or .svg file extension as desired.

My mistake, the correct name to look for is circle-white; us-state was the corresponding value in Mapbox Streets v7. Despite the more generic name, we don’t have to worry about mistakenly showing a U.S. state route shield where a white circle is actually warranted, because the legacy shields only cover U.S. state routes and a few other basic U.S. route networks that should never be marked by white circles. Anything else in the U.S. or any other country would correctly fall back again to the Mapbox-designed white circle shield.