Add possible values for landcover, landuse, park doc

layers/landcover/landcover.yaml

@@ -6,13 +6,48 @@ layer:
         is to style wood (`class=wood`) and grass (`class=`grass`) areas.
   buffer_size: 4
   fields:
-    class: |
-        More generalized groups of either `farmland`, `ice`, `wood`, `grass`
-        or `wetland`.
-        Use this to assign general colors to the landcover.
-    subclass: |
-        Original value of either the `landuse`, `natural`, `leisure` or
-        `wetland` tag. Use this to do more precise styling.
+    class:
+      description: |
+          Use the **class** to assign natural colors for **landcover**.
+      values:
+      - farmland
+      - ice
+      - wood
+      - grass
+      - wetland
+    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
+      - farm
+      - farmland
+      - orchard
+      - plant_nursery
+      - vineyard
+      - grass
+      - grassland
+      - meadow
+      - forest
+      - village_green
+      - recreation_ground
+      - park
+      - wetland
+      - grassland
+      - bog
+      - swamp
+      - wet_meadow
+      - marsh
+      - reedbed
+      - saltern
+      - tidalflat
+      - saltmarsh
+      - mangrove
   datasource:
     geometry_field: geometry
     query: (SELECT geometry, class, subclass FROM layer_landcover(!bbox!, z(!scale_denominator!))) AS t

layers/landuse/landuse.yaml

@@ -5,17 +5,28 @@ layer:
       from Natural Earth data for residential (urban) areas and at higher zoom levels mostly OSM `landuse` tags.
   buffer_size: 4
   fields:
-    class: |
-        Original value of either the `amenity`, `landuse`, `leisure`
-        tag.  Use this to assign special colors to areas.
-        Either `school`, `university`, `kindergarten`, `college`,
-        `library`, `hospital` (from the
-        [`amenity`](http://wiki.openstreetmap.org/wiki/Key:amenity) key)
-        or `railway`, `cemetery`, `military`, `residential`,
-        `commercial`, `industrial`, `retail` (from the
-        [`landuse`](http://wiki.openstreetmap.org/wiki/Key:landuse) key)
-        as well as `stadium` (from the
-        [`leisure`](http://wiki.openstreetmap.org/wiki/Key:leisure) key).
+    class:
+      description: |
+          Use the **class** to assign special colors to areas.
+          Original value of either the
+          [`amenity`](http://wiki.openstreetmap.org/wiki/Key:amenity),
+          [`landuse`](http://wiki.openstreetmap.org/wiki/Key:landuse),
+          or [`leisure`](http://wiki.openstreetmap.org/wiki/Key:leisure) tag.
+      values:
+      - school
+      - university
+      - kindergarten
+      - college
+      - library
+      - hospital
+      - railway
+      - cemetery
+      - military
+      - residential
+      - commercial
+      - industrial
+      - retail
+      - stadium
   datasource:
     geometry_field: geometry
     query: (SELECT geometry, class FROM layer_landuse(!bbox!, z(!scale_denominator!))) AS t

layers/park/park.yaml

@@ -4,8 +4,12 @@ layer:
       The park layer contains parks from OpenStreetMap tagged with either [`boundary=national_park`](http://wiki.openstreetmap.org/wiki/Tag:boundary%3Dnational_park) or [`leisure=nature_reserve`](http://wiki.openstreetmap.org/wiki/Tag:leisure%3Dnature_reserve).
   buffer_size: 4
   fields:
-    class: |
-        Either `national_park` or `nature_reserve`.
+    class:
+      description: |
+          Use the **class** to differentiate between different parks.
+      values:
+      - national_park
+      - nature_reserve
   datasource:
     geometry_field: geometry
     query: (SELECT geometry, class FROM layer_park(!bbox!, z(!scale_denominator!))) AS t