[WIP] Highway shields

[kylebarron]

Preview: https://maputnik.github.io/editor/?style=https://raw.githubusercontent.com/kylebarron/osm-liberty/highway-shields/style.json

Included tags:

• us-interstate
• us-highway
• us-state
• ca-transcanada
• gb-motorway; included but I think it's wrong
• gb-trunk

Notes:

• How big should the icons be? Right now they're sized to a height of 30px, which I think is a little too big. Maybe try 20px height next?
• The filtering in the style means that if there were a US highway/state highway/interstate with a 4-character identifier it wouldn't get shown at all. This is because the fallback square road sign doesn't show for these tags, but the specialized shields only show for <=3 character refs. Not sure how big of a problem this is, but the logic in the style could be improved to fix this.
• The "Interstate" text on the interstate highway shield is illegible so maybe that should be removed?
• I was trying to find the correct symbols for gb-trunk and gb-motorway but they were hard to find. Is this correct?
• Currently the style is pointing to the sprite on my branch. If/when this is merged, that URL should be changed to point back to the master branch.

Screenshots:

I think this is wrong:

Closes #78.

[kylebarron]

Any comment/suggestion? @pathmapper @orangemug

I think the icons are too big, but I'd be happy to hear suggestions before changing anything.

[boldtrn]

The shields look really nice, awesome!

I think the icons are too big

In my opinion yes. I had a look at the changes, for example for road_shield_us-interstate-2, I'd set

"minzoom": 6,
"text-size": 8,
"icon-size": 0.6,
"symbol-placement": "line", (I am not 100% sure about that)

I think this is wrong:

Yes, I think in the UK the shields for motorways should be blue. For example.

[kylebarron]

Interesting. I was modifying the source SVGs to change the shield size; I didn't realize you could just pass icon-size to change the size.

I'll try to update the PR soon.

[pathmapper]

Thanks for the PR @kylebarron, the shields are looking great!

I also do also think that the icons could be a smaller.

I was modifying the source SVGs to change the shield size; I didn't realize you could just pass icon-size to change the size.

I think for testing and finding the right size, using icon-size is a good option, but once the desired size is found I would prefer to have the right size in the sprite to avoid rescaling a reduce the sprite size (exception: If an icon is used in several sizes for the style, I think it's best to have the biggest size in the sprite and use icon-size for the smaller ones.)

[pathmapper]

I was trying to find the correct symbols for gb-trunk and gb-motorway but they were hard to find. Is this correct ?

@orangemug could you give any insight regarding the UK shields?