openmaptiles/layers/transportation/transportation.yaml

layer:
  id: "transportation"
  description: |
      Roads or [`highway`](http://wiki.openstreetmap.org/wiki/Key:highway) in OpenStreetMap lingo.
      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: |
        Either `motorway`, `major_road` (containing `trunk`, `primary`, `secondary` and `tertiary` roads) and `minor_road` (less important roads in the hierarchy like `residential` or `service`) or `path` for
        non vehicle paths (such as `cycleway` or `footpath`).
    subclass: |
        Original value of the [`highway`](http://wiki.openstreetmap.org/wiki/Key:highway) tag. Use this to do more
        precise styling.
    properties: |
        Additional properties describing the nature of road.
        The properties `bridge` and `tunnel` can be combined with `oneway` as well. So to style all bridges the same you
        should style both the properties `bridge` and `bridge:oneway`.
        Properties can be one of `bridge:oneway`, `tunnel:oneway`, `ramp`, `ford`, `bridge`, `tunnel` or`oneway`.
  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
  - ./ne_global_roads.sql
  - ./layer.sql
datasources:
  - type: imposm3
    mapping_file: ./mapping.yaml