layer:
  id: "transportation"
  description: |
      **transportation** contains roads and railways.
      This layer is directly derived from the OSM road hierarchy.
      At lower zoom levels major highways from Natural Earth are used.
      It contains all roads from motorways to primary, secondary and
      tertiary roads to residential roads and
      foot paths. Styling the roads is the most essential part of the map.
      The `transportation` layer also contains polygons for features like plazas.
  buffer_size: 4
  srs: +proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0.0 +k=1.0 +units=m +nadgrids=@null +wktext +no_defs +over
  fields:
    class:
      description: |
          Distinguish between more and less important roads or railways.
          Class is derived from the value of the
          [`highway`](http://wiki.openstreetmap.org/wiki/Key:highway) or
          [`railway`](http://wiki.openstreetmap.org/wiki/Key:railway) tag.
      values:
      - motorway
      - trunk
      - primary
      - secondary
      - tertiary
      - minor
      - service
      - track
      - path
      - raceway
      - rail
      - transit
    brunnel:
      description: |
          Mark whether way is a tunnel or bridge.
      values:
        - bridge
        - tunnel
        - ford
    oneway:
      description: |
          Mark with `1` whether way is a oneway (in the direction of the way)
          or not with `0`.
      values: [0, 1]
    ramp:
      description: |
          Mark with `1` whether way is a ramp (link or steps)
          or not with `0`.
      values: [0, 1]
    service:
      description: |
          Original value of the [`service`](http://wiki.openstreetmap.org/wiki/Key:service) tag.
      values:
      - spur
      - yard
      - siding
      - crossover
      - driveway
      - alley
      - parking_aisle
  datasource:
    geometry_field: geometry
    srid: 900913
    query: (SELECT geometry, class, oneway, ramp, brunnel, service FROM layer_transportation(!bbox!, z(!scale_denominator!))) AS t
schema:
  - ./class.sql
  - ./update_transportation_merge.sql
  - ./layer.sql
datasources:
  - type: imposm3
    mapping_file: ./mapping.yaml