Convert to tile area

layers/water_name/water_name.sql

@@ -6,7 +6,7 @@ CREATE OR REPLACE FUNCTION layer_water_name(bbox geometry, zoom_level integer)
             (
                 osm_id       bigint,
                 geometry     geometry,
-                area         float,
+                tile_area    float,
                 name         text,
                 name_en      text,
                 name_de      text,
@@ -44,7 +44,7 @@ SELECT
         ELSE osm_id * 10 + 1
         END AS osm_id_hash,
     geometry,
-    area,
+    POWER(4,zoom_level) * area / (405279708033600 * COS(ST_Y(ST_Transform(geometry,4326))*PI()/180)) as tile_area,
     name,
     COALESCE(NULLIF(name_en, ''), name) AS name_en,
     COALESCE(NULLIF(name_de, ''), name, name_en) AS name_de,

layers/water_name/water_name.yaml

@@ -19,7 +19,7 @@ layer:
       - lake
       - sea
       - ocean
-    area: Surface area of the feature, in square meters
+    tile_area: Surface area of the feature, in tiles (1.0 = feature is the size of 1 tile)
     intermittent:
       description: |
         Mark with `1` if it is an [intermittent](http://wiki.openstreetmap.org/wiki/Key:intermittent) lake.
@@ -31,7 +31,7 @@ layer:
     key_field: osm_id
     key_field_as_attribute: no
     srid: 900913
-    query: (SELECT osm_id, geometry, area, name, name_en, name_de, {name_languages}, class, intermittent FROM layer_water_name(!bbox!, z(!scale_denominator!))) AS t
+    query: (SELECT osm_id, geometry, tile_area, name, name_en, name_de, {name_languages}, class, intermittent FROM layer_water_name(!bbox!, z(!scale_denominator!))) AS t
 schema:
   - ./update_marine_point.sql
   - ./update_water_lakeline.sql