data.yml

_prefs:
  disabled: []
  inspector: false
  mapid: ''
  rev: ''
  saveCenter: false
name: OSM Clear
description: A style designed for use with ClearTables
attribution: 'Data © OpenStreetMap contributors'
center:
  - 0
  - 0
  - 4
minzoom: 0
maxzoom: 16
# Various parts to be included later on
_parts:
  # Extents are used for tilemill, and don't actually make it to the generated XML
  extents: &extents
    extent: -20037508,-20037508,20037508,20037508
    srs-name: "900913"
    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"
  osm2pgsql: &osm2pgsql
    type: postgis
    dbname: "gis"
    key_field: ""
    geometry_field: "way"
    extent: "-20037508,-20037508,20037508,20037508"
Layer:
  - id: water
    geometry: polygon
    <<: *extents
    Datasource:
      <<: *osm2pgsql
      table: |-
        (SELECT
            way
          FROM water_areas
          WHERE way_area > 0.01*!pixel_width!::real*!pixel_height!::real
            AND z(!scale_denominator!) >= 6
        UNION ALL
        SELECT
            way
          FROM ocean
          WHERE z(!scale_denominator!) >= 10
        UNION ALL
        SELECT
            way
          FROM simplified_ocean
          WHERE z(!scale_denominator!) < 10
        ) AS water
  - id: waterways
    geometry: linestring
    <<: *extents
    Datasource:
      <<: *osm2pgsql
      table: |-
        (SELECT
            way,
            waterway,
            brunnel,
            intermittent
          FROM waterways
          WHERE waterway IN ('river')
            OR (z(!scale_denominator!) >= 7 AND waterway IN ('canal'))
            OR (z(!scale_denominator!) >= 11 AND waterway IN ('stream'))
            OR (z(!scale_denominator!) >= 13 AND waterway IN ('drain', 'ditch'))
          ORDER BY layer
        ) AS waterways
    properties:
      minzoom: 5
  - id: buildings
    geometry: polygon
    <<: *extents
    Datasource:
      <<: *osm2pgsql
      table: |-
        (SELECT
            way,
            -- 3.66 is obtained by correlating the heights and level data in OSM
            -- raising to a power < 1 reduces the height range displayed which looks better
            least(greatest(3, COALESCE(height,levels*3.66,5)),400)^.7 AS render_height
          FROM buildings
          WHERE way_area > 0.01*!pixel_width!::real*!pixel_height!::real
          ORDER BY render_height, ST_YMin(way) DESC
        ) AS buildings
    properties:
      minzoom: 12
  - id: transportation-back-casing
    geometry: linestring
    <<: *extents
    Datasource:
      <<: *osm2pgsql
      table: &transport_query |-
        (SELECT
            way,
            class::text,
            layer,
            ramp,
            brunnel::text -- does this need to be text?
          FROM (SELECT
              way,
              class,
              layer,
              brunnel,
              ramp,
              NULL::real AS way_area
            FROM roads
            WHERE class IN ('motorway','trunk','primary')
              OR (z(!scale_denominator!) >= 6 AND class IN ('secondary'))
              OR (z(!scale_denominator!) >= 8 AND class IN ('tertiary'))
              OR (z(!scale_denominator!) >= 11 AND class IN ('minor'))
              OR z(!scale_denominator!) >= 12
          UNION ALL
          SELECT
              way,
              class,
              layer,
              brunnel,
              NULL::boolean AS ramp,
              NULL::real AS way_area
            FROM rail
          UNION ALL
          SELECT
              way,
              class,
              layer,
              brunnel,
              NULL::boolean AS ramp,
              way_area
            FROM road_areas
            WHERE z(!scale_denominator!) >= 12
            ORDER BY layer,
              class,
              way_area DESC NULLS LAST) AS q
        ) AS transportation
    properties:
      minzoom: 4
  - id: transportation
    geometry: linestring
    <<: *extents
    Datasource:
      <<: *osm2pgsql
      table: *transport_query
    advanced: {}
    properties:
      group-by: layer
      minzoom: 4
  - id: aeroway
    geometry: linestring
    <<: *extents
    Datasource:
      <<: *osm2pgsql
      table: |-
        (SELECT
            way,
            aeroway
          FROM
            aeroway_line
        ) AS aeroway
    properties:
      minzoom: 10
  - id: place
    geometry: point
    <<: *extents
    Datasource:
      <<: *osm2pgsql
      table: |-
        (SELECT
            way,
            name,
            class::text,
            rank::text
          FROM
            (SELECT
              DISTINCT ON (ST_SnapToGrid(way, !pixel_width!::real*8, !pixel_height!::real*8))
                *
              FROM
                (SELECT
                    way,
                    name,
                    class,
                    rank,
                    population,
                    NULL::float AS way_area
                  FROM place_point
                  WHERE way && !bbox!
                UNION ALL
                SELECT
                    ST_PointOnSurface(way) AS way,
                    name,
                    class,
                    rank,
                    population,
                    way_area
                  FROM place_polygon
                  WHERE way && !bbox!
                ) AS p
              WHERE way && !bbox!
                AND name IS NOT NULL
                AND rank IN ('city')
                  OR (z(!scale_denominator!) >= 6 AND rank >='town' AND class = 'settlement')
                  OR (z(!scale_denominator!) >= 8 AND rank >='village' AND class = 'settlement')
                  OR (z(!scale_denominator!) >= 10 AND rank >='hamlet' AND class = 'settlement')
                  -- todo: add subregions
              -- Place labels are well-known for being finicky for cut-off labels
              -- This includes terms which aren't needed directly, but are required
              -- to get consistent ordering across tile bounds.
              ORDER BY
                ST_SnapToGrid(way, !pixel_width!::real*8, !pixel_height!::real*8),
                CASE class
                  WHEN 'settlement' THEN 10
                  WHEN 'subregion' THEN 5
                  WHEN 'locality' THEN 2 ELSE 1
                END DESC,
                p.rank DESC, -- order by the enum, not text
                population DESC NULLS LAST,
                way_area DESC NULLS LAST,
                length(name) DESC,
                name
            ) AS p
          -- This is the same ordering as above, just without the grid.
          ORDER BY
            CASE class
              WHEN 'settlement' THEN 10
              WHEN 'subregion' THEN 5
              WHEN 'locality' THEN 2 ELSE 1
            END DESC,
            p.rank DESC, -- order by the enum, not text
            population DESC NULLS LAST,
            way_area DESC NULLS LAST,
            length(name) DESC,
            name
        ) AS place
    properties:
      "buffer-size": 192
  - id: roads-text
    geometry: linestring
    <<: *extents
    Datasource:
      <<: *osm2pgsql
      table: |-
        (SELECT
            way,
            name,
            class::text,
            layer,
            brunnel::text
          FROM roads
          WHERE name IS NOT NULL
            AND class IN ('motorway','trunk','primary')
              OR (z(!scale_denominator!) >= 6 AND class IN ('secondary'))
              OR (z(!scale_denominator!) >= 8 AND class IN ('tertiary'))
              OR (z(!scale_denominator!) >= 11 AND class IN ('minor'))
              OR z(!scale_denominator!) >= 12
          ORDER BY layer, class) AS road_text
    properties:
      minzoom: 4