layer:
  id: "transportation"
  description: |
      **transportation** containsrRoads and railways.
      This layer is directly derived from the OSM road hierarchy which is why it is called `highway`. Only
      at zoom level 4 to 7 some major highways from Natural Earth are used otherwise it is only OSM data.
      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. If you can put enough effort into it
      makes sense to carefully style each `subclass`. For more comfortable styling you can also just style the roads
      by `class`. Roads can have different properties, a road can have `oneway=yes` and `bridge=yes` at the same time.
      These properties are reflected in the field `properties`.
      This layer is not meant for labelling the roads (the purpose of the layer `highway_name`).

      The `highway` layer also contains polygons for things 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.
      values:
      - motorway
      - trunk
      - primary
      - secondary
      - tertiary
      - minor
      - track
      - service
      - path
    subclass:
      description: |
          Use **subclass** to do more precise styling.
          Original value of the
          [`highway`](http://wiki.openstreetmap.org/wiki/Key:highway) or
          [`railway`](http://wiki.openstreetmap.org/wiki/Key:railway) tag.
      values:
      - motorway
      - motorway_link
      - trunk
      - trunk_link
      - primary
      - primary_link
      - secondary
      - secondary_link
      - tertiary
      - tertiary_link
      - unclassified
      - residential
      - road
      - living_street
      - raceway
      - construction
      - track
      - service
      - path
      - cycleway
      - bridleway
      - footway
      - corridor
      - crossing
      - pedestrian
      - rail
      - narrow_gauge
      - preserved
      - funicular
      - subway
      - light_rail
      - monorail
      - tram
    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, subclass, oneway, ramp, brunnel, service FROM layer_transportation(!bbox!, z(!scale_denominator!))) AS t
schema:
  - ./class.sql
  - ./layer.sql
datasources:
  - type: imposm3
    mapping_file: ./mapping.yaml