layer:
  id: "landcover"
  requires:
    tables:
      - ne_10m_antarctic_ice_shelves_polys
      - ne_10m_glaciated_areas
      - ne_50m_antarctic_ice_shelves_polys
      - ne_50m_glaciated_areas
      - ne_110m_glaciated_areas
  description: |
      Landcover is used to describe the physical material at the surface of the earth. At lower zoom levels this is
      from Natural Earth data for glaciers and ice shelves and at higher zoom levels the landcover is [implied by OSM tags](http://wiki.openstreetmap.org/wiki/Landcover). The most common use case for this layer
        is to style wood (`class=wood`) and grass (`class=grass`) areas.
  buffer_size: 4
  fields:
    class:
      description: |
          Use the **class** to assign natural colors for **landcover**.
      values:
        farmland:
          subclass: ['farmland', 'farm', 'orchard', 'vineyard', 'plant_nursery']
        ice:
          subclass: ['glacier', 'ice_shelf']
        wood:
          subclass: ['wood', 'forest']
        rock:
          subclass: ['bare_rock', 'scree']
        grass:
          subclass: ['fell', 'grassland', 'heath', 'scrub', 'shrubbery', 'tundra', 'grass', 'meadow', 'allotments', 'park', 'village_green', 'recreation_ground', 'garden', 'golf_course']
        wetland:
          subclass: ['wetland', 'bog', 'swamp', 'wet_meadow', 'marsh', 'reedbed', 'saltern', 'tidalflat', 'saltmarsh', 'mangrove']
        sand:
          subclass: ['beach', 'sand', 'dune']
    subclass:
      description: |
          Use **subclass** to do more precise styling.
          Original value of either the
          [`natural`](http://wiki.openstreetmap.org/wiki/Key:natural),
          [`landuse`](http://wiki.openstreetmap.org/wiki/Key:landuse),
          [`leisure`](http://wiki.openstreetmap.org/wiki/Key:leisure),
          or [`wetland`](http://wiki.openstreetmap.org/wiki/Key:wetland) tag.
      values:
      - allotments
      - bare_rock
      - beach
      - bog
      - dune
      - scrub
      - shrubbery
      - farm
      - farmland
      - fell
      - forest
      - garden
      - glacier
      - grass
      - grassland
      - golf_course
      - heath
      - mangrove
      - marsh
      - meadow
      - orchard
      - park
      - plant_nursery
      - recreation_ground
      - reedbed
      - saltern
      - saltmarsh
      - sand
      - scree
      - swamp
      - tidalflat
      - tundra
      - village_green
      - vineyard
      - wet_meadow
      - wetland
      - wood
  datasource:
    geometry_field: geometry
    query: (SELECT geometry, class, subclass FROM layer_landcover(!bbox!, z(!scale_denominator!))) AS t
schema:
  - ./generalized.sql
  - ./landcover.sql
datasources:
  - type: imposm3
    mapping_file: ./mapping.yaml