Excluding bridges for higher-zoom ref labeling

[pnorman]

Currently the #roads-text-ref layer uses the following selectors (svg_shields branch)

  [highway = 'motorway'][length < 12] {
    [zoom >= 13] {
      ...
    }
  }
  [highway = 'trunk'][zoom >= 13] {
    ...
  }
  [highway = 'primary'][zoom >= 13] {
    ...
  }
  [highway = 'secondary'][bridge = 'no'][zoom >= 13] {
    ...
  }
  [highway = 'tertiary'][bridge = 'no'][zoom >= 13] {
    ...
  }
  [highway = 'unclassified'],
  [highway = 'residential'] {
    [zoom >= 15][bridge = 'no'] {
      ...
    }
  }
  [highway = 'runway'],
  [highway = 'taxiway'] {
    [zoom >= 15][bridge = 'no'] {
      ...
    }
  }

bridge = 'no' is true for bridge values other than yes, true, or 1. I've tried to figure out the logic here, but find none. @gravitystorm, do you have any ideas? I presume this is carried over from the old Mapnik XML.

All I can think of is an attempt to stop labeling small components. But then why only some highway types?

[gravitystorm]

I don't have any reasoning, it's just carried over. Perhaps the black text clashes with the black bridge outlines? Whichever, it should be consistent.

[matthijsmelissen]

I think the reason is that bridge segments are usually very short, so this might result in repetition of the same name on a small interval.

[AndrewHain]

Segments without room to display a name will in any case not have one, whether they are one way, bus routes or whatever, no need for a special case for bridges.

[pnorman]

Segments without room to display a name will in any case not have one

This is true for TextSymbolizers, but I don't think it's true for ShieldSymbolizers.

[matthijsmelissen]

@pnorman Can I assign this issue to you?