Better generalization for `landuse=residential`. (#1414)

This PR creates larger polygons of `residential` land-use areas for upper zoom levels (especially for zoom 6 - 10).

Clusters are created with the same logic as for [`building on z13`](b14da2eafb/layers/building/update_building.sql (L34-L49)).

The generalization of land-use prolongs the `import-sql` step of the `landuse` layer. But it is still faster than the `building z13` generalization which with the parallel importing keeps the whole `import-sql` time untouched.

layers/landuse/landuse.sql

@@ -35,6 +35,188 @@ WHERE scalerank <= 2
     ) /* DELAY_MATERIALIZED_VIEW_CREATION */ ;
 CREATE INDEX IF NOT EXISTS ne_50m_urban_areas_gen_z4_idx ON ne_50m_urban_areas_gen_z4 USING gist (geometry);
 
+-- etldoc: osm_landuse_polygon_gen_z6 ->  osm_landuse_polygon_gen_z6_union
+-- etldoc: osm_residential_gen_z6 ->  osm_landuse_polygon_gen_z6_union
+CREATE OR REPLACE VIEW osm_landuse_polygon_gen_z6_union AS
+(
+       SELECT osm_id,
+                geometry,
+                landuse,
+                amenity,
+                leisure,
+                tourism,
+                place,
+                waterway
+         FROM osm_landuse_polygon_gen_z6
+		 WHERE landuse <> 'residential'
+       UNION ALL
+       SELECT NULL::bigint AS osm_id,
+              geometry,
+              'residential' AS landuse,
+              '' AS amenity,
+              '' AS leisure,
+              '' AS tourism,
+              '' AS place,
+              '' AS waterway
+         FROM osm_residential_gen_z6
+);
+
+-- etldoc: osm_landuse_polygon_gen_z7 ->  osm_landuse_polygon_gen_z7_union
+-- etldoc: osm_residential_gen_z7 ->  osm_landuse_polygon_gen_z7_union
+CREATE OR REPLACE VIEW osm_landuse_polygon_gen_z7_union AS
+(
+       SELECT osm_id,
+                geometry,
+                landuse,
+                amenity,
+                leisure,
+                tourism,
+                place,
+                waterway
+         FROM osm_landuse_polygon_gen_z7
+		 WHERE landuse <> 'residential'
+       UNION ALL
+       SELECT NULL::bigint AS osm_id,
+              geometry,
+              'residential' AS landuse,
+              '' AS amenity,
+              '' AS leisure,
+              '' AS tourism,
+              '' AS place,
+              '' AS waterway
+         FROM osm_residential_gen_z7
+);
+
+-- etldoc: osm_landuse_polygon_gen_z8 ->  osm_landuse_polygon_gen_z8_union
+-- etldoc: osm_residential_gen_z8 ->  osm_landuse_polygon_gen_z8_union
+CREATE OR REPLACE VIEW osm_landuse_polygon_gen_z8_union AS
+(
+       SELECT osm_id,
+                geometry,
+                landuse,
+                amenity,
+                leisure,
+                tourism,
+                place,
+                waterway
+         FROM osm_landuse_polygon_gen_z8
+		 WHERE landuse <> 'residential'
+       UNION ALL
+       SELECT NULL::bigint AS osm_id,
+              geometry,
+              'residential' AS landuse,
+              '' AS amenity,
+              '' AS leisure,
+              '' AS tourism,
+              '' AS place,
+              '' AS waterway
+         FROM osm_residential_gen_z8
+);
+
+-- etldoc: osm_landuse_polygon_gen_z9 ->  osm_landuse_polygon_gen_z9_union
+-- etldoc: osm_residential_gen_z9 ->  osm_landuse_polygon_gen_z9_union
+CREATE OR REPLACE VIEW osm_landuse_polygon_gen_z9_union AS
+(
+       SELECT osm_id,
+                geometry,
+                landuse,
+                amenity,
+                leisure,
+                tourism,
+                place,
+                waterway
+         FROM osm_landuse_polygon_gen_z9
+		 WHERE landuse <> 'residential'
+       UNION ALL
+       SELECT NULL::bigint AS osm_id,
+              geometry,
+              'residential' AS landuse,
+              '' AS amenity,
+              '' AS leisure,
+              '' AS tourism,
+              '' AS place,
+              '' AS waterway
+         FROM osm_residential_gen_z9
+);
+
+-- etldoc: osm_landuse_polygon_gen_z10 ->  osm_landuse_polygon_gen_z10_union
+-- etldoc: osm_residential_gen_z10 ->  osm_landuse_polygon_gen_z10_union
+CREATE OR REPLACE VIEW osm_landuse_polygon_gen_z10_union AS
+(
+       SELECT osm_id,
+                geometry,
+                landuse,
+                amenity,
+                leisure,
+                tourism,
+                place,
+                waterway
+         FROM osm_landuse_polygon_gen_z10
+		 WHERE landuse <> 'residential'
+       UNION ALL
+       SELECT NULL::bigint AS osm_id,
+              geometry,
+              'residential' AS landuse,
+              '' AS amenity,
+              '' AS leisure,
+              '' AS tourism,
+              '' AS place,
+              '' AS waterway
+         FROM osm_residential_gen_z10
+);
+
+-- etldoc: osm_landuse_polygon_gen_z11 ->  osm_landuse_polygon_gen_z11_union
+-- etldoc: osm_residential_gen_z11 ->  osm_landuse_polygon_gen_z11_union
+CREATE OR REPLACE VIEW osm_landuse_polygon_gen_z11_union AS
+(
+       SELECT osm_id,
+                geometry,
+                landuse,
+                amenity,
+                leisure,
+                tourism,
+                place,
+                waterway
+         FROM osm_landuse_polygon_gen_z11
+		 WHERE landuse <> 'residential'
+       UNION ALL
+       SELECT NULL::bigint AS osm_id,
+              geometry,
+              'residential' AS landuse,
+              '' AS amenity,
+              '' AS leisure,
+              '' AS tourism,
+              '' AS place,
+              '' AS waterway
+         FROM osm_residential_gen_z11
+);
+
+-- etldoc: osm_landuse_polygon_gen_z12 ->  osm_landuse_polygon_gen_z12_union
+-- etldoc: osm_residential_gen_z12 ->  osm_landuse_polygon_gen_z12_union
+CREATE OR REPLACE VIEW osm_landuse_polygon_gen_z12_union AS
+(
+       SELECT osm_id,
+                geometry,
+                landuse,
+                amenity,
+                leisure,
+                tourism,
+                place,
+                waterway
+         FROM osm_landuse_polygon_gen_z12
+		 WHERE landuse <> 'residential'
+       UNION ALL
+       SELECT NULL::bigint AS osm_id,
+              geometry,
+              'residential' AS landuse,
+              '' AS amenity,
+              '' AS leisure,
+              '' AS tourism,
+              '' AS place,
+              '' AS waterway
+         FROM osm_residential_gen_z12
+);
+
 -- etldoc: layer_landuse[shape=record fillcolor=lightpink, style="rounded,filled",
 -- etldoc:     label="layer_landuse |<z4> z4|<z5> z5|<z6> z6|<z7> z7|<z8> z8|<z9> z9|<z10> z10|<z11> z11|<z12> z12|<z13> z13|<z14> z14+" ] ;
 
@@ -83,7 +265,7 @@ FROM (
          FROM ne_50m_urban_areas_gen_z5
          WHERE zoom_level = 5
          UNION ALL
-         -- etldoc: osm_landuse_polygon_gen_z6 -> layer_landuse:z6
+         -- etldoc: osm_landuse_polygon_gen_z6_union -> layer_landuse:z6
          SELECT osm_id,
                 geometry,
                 landuse,
@@ -92,10 +274,10 @@ FROM (
                 tourism,
                 place,
                 waterway
-         FROM osm_landuse_polygon_gen_z6
+         FROM osm_landuse_polygon_gen_z6_union
          WHERE zoom_level = 6
          UNION ALL
-         -- etldoc: osm_landuse_polygon_gen_z7 -> layer_landuse:z7
+         -- etldoc: osm_landuse_polygon_gen_z7_union -> layer_landuse:z7
          SELECT osm_id,
                 geometry,
                 landuse,
@@ -104,10 +286,10 @@ FROM (
                 tourism,
                 place,
                 waterway
-         FROM osm_landuse_polygon_gen_z7
+         FROM osm_landuse_polygon_gen_z7_union
          WHERE zoom_level = 7
          UNION ALL
-         -- etldoc: osm_landuse_polygon_gen_z8 -> layer_landuse:z8
+         -- etldoc: osm_landuse_polygon_gen_z8_union -> layer_landuse:z8
          SELECT osm_id,
                 geometry,
                 landuse,
@@ -116,10 +298,10 @@ FROM (
                 tourism,
                 place,
                 waterway
-         FROM osm_landuse_polygon_gen_z8
+         FROM osm_landuse_polygon_gen_z8_union
          WHERE zoom_level = 8
          UNION ALL
-         -- etldoc: osm_landuse_polygon_gen_z9 -> layer_landuse:z9
+         -- etldoc: osm_landuse_polygon_gen_z9_union -> layer_landuse:z9
          SELECT osm_id,
                 geometry,
                 landuse,
@@ -128,10 +310,10 @@ FROM (
                 tourism,
                 place,
                 waterway
-         FROM osm_landuse_polygon_gen_z9
+         FROM osm_landuse_polygon_gen_z9_union
          WHERE zoom_level = 9
          UNION ALL
-         -- etldoc: osm_landuse_polygon_gen_z10 -> layer_landuse:z10
+         -- etldoc: osm_landuse_polygon_gen_z10_union -> layer_landuse:z10
          SELECT osm_id,
                 geometry,
                 landuse,
@@ -140,10 +322,10 @@ FROM (
                 tourism,
                 place,
                 waterway
-         FROM osm_landuse_polygon_gen_z10
+         FROM osm_landuse_polygon_gen_z10_union
          WHERE zoom_level = 10
          UNION ALL
-         -- etldoc: osm_landuse_polygon_gen_z11 -> layer_landuse:z11
+         -- etldoc: osm_landuse_polygon_gen_z11_union -> layer_landuse:z11
          SELECT osm_id,
                 geometry,
                 landuse,
@@ -152,10 +334,10 @@ FROM (
                 tourism,
                 place,
                 waterway
-         FROM osm_landuse_polygon_gen_z11
+         FROM osm_landuse_polygon_gen_z11_union
          WHERE zoom_level = 11
          UNION ALL
-         -- etldoc: osm_landuse_polygon_gen_z12 -> layer_landuse:z12
+         -- etldoc: osm_landuse_polygon_gen_z12_union -> layer_landuse:z12
          SELECT osm_id,
                 geometry,
                 landuse,
@@ -164,7 +346,7 @@ FROM (
                 tourism,
                 place,
                 waterway
-         FROM osm_landuse_polygon_gen_z12
+         FROM osm_landuse_polygon_gen_z12_union
          WHERE zoom_level = 12
          UNION ALL
          -- etldoc: osm_landuse_polygon_gen_z13 -> layer_landuse:z13

layers/landuse/landuse.yaml

@@ -49,6 +49,7 @@ layer:
     query: (SELECT geometry, class FROM layer_landuse(!bbox!, z(!scale_denominator!))) AS t
 schema:
   - ./class.sql
+  - ./prep_landuse.sql
   - ./landuse.sql
 datasources:
   - type: imposm3

layers/landuse/prep_landuse.sql

@@ -0,0 +1,176 @@
+DROP TABLE IF EXISTS cluster_zres14;
+CREATE TABLE cluster_zres14 AS 
+(
+WITH single_geom AS (
+        SELECT (ST_Dump(geometry)).geom AS geometry
+        FROM osm_landuse_polygon 
+        WHERE landuse='residential'
+    )
+    SELECT ST_ClusterDBSCAN(geometry, eps := zres(14), minpoints := 1) over () AS cid,
+           geometry
+    FROM single_geom
+);
+CREATE INDEX ON cluster_zres14 USING gist(geometry);
+
+
+DROP TABLE IF EXISTS cluster_zres14_union;
+CREATE TABLE cluster_zres14_union AS (
+SELECT ST_Buffer(
+            ST_Union(
+                ST_Buffer(
+                    ST_SnapToGrid(geometry, 0.01)
+                    , zres(14), 'join=mitre'
+                )
+            ),-zres(14), 'join=mitre'
+        ) AS geometry
+FROM cluster_zres14
+GROUP BY cid
+);
+CREATE INDEX ON cluster_zres14_union USING gist(geometry);
+
+
+DROP TABLE IF EXISTS cluster_zres12;
+CREATE TABLE cluster_zres12 AS 
+(
+WITH single_geom AS (
+    SELECT (ST_Dump(geometry)).geom AS geometry
+    FROM osm_landuse_polygon 
+    WHERE landuse='residential'
+    )
+    SELECT ST_ClusterDBSCAN(geometry, eps := zres(12), minpoints := 1) over () AS cid,
+           geometry
+    FROM single_geom
+);
+CREATE INDEX ON cluster_zres12 USING gist(geometry);
+
+
+DROP TABLE IF EXISTS cluster_zres12_union;
+CREATE TABLE cluster_zres12_union AS 
+(
+SELECT ST_Buffer(
+            ST_Union(
+                ST_Buffer(
+                    ST_SnapToGrid(geometry, 1)
+                        , zres(12), 'join=mitre'
+                    )
+                ), -zres(12), 'join=mitre'
+            ) AS geometry
+FROM cluster_zres12
+GROUP BY cid
+);
+CREATE INDEX ON cluster_zres12_union USING gist(geometry);
+
+
+DROP TABLE IF EXISTS cluster_zres9;
+CREATE TABLE cluster_zres9 AS 
+(
+WITH single_geom AS (
+        SELECT (ST_Dump(geometry)).geom AS geometry
+        FROM osm_landuse_polygon 
+        WHERE landuse='residential'
+    )
+    SELECT ST_ClusterDBSCAN(geometry, eps := zres(9), minpoints := 1) over () AS cid,
+           geometry
+    FROM single_geom
+);
+CREATE INDEX ON cluster_zres9 USING gist(geometry);
+
+
+DROP TABLE IF EXISTS cluster_zres9_union;
+CREATE TABLE cluster_zres9_union AS 
+(
+SELECT ST_Buffer(
+            ST_Union(
+                ST_Buffer(
+                    ST_SnapToGrid(geometry, 1)
+                        , zres(9), 'join=mitre'
+                    )
+                ), -zres(9), 'join=mitre'
+            ) AS geometry
+FROM cluster_zres9
+GROUP BY cid
+);
+CREATE INDEX ON cluster_zres9_union USING gist(geometry);
+
+-- For z6
+-- etldoc: osm_landuse_polygon ->  osm_residential_gen_z6
+DROP TABLE IF EXISTS osm_residential_gen_z6 CASCADE;
+CREATE TABLE osm_residential_gen_z6 AS
+(
+SELECT ST_SimplifyVW(geometry, power(zres(6), 2)) AS geometry
+FROM cluster_zres9_union
+WHERE ST_Area(geometry) > power(zres(6), 2)
+);
+CREATE INDEX ON osm_residential_gen_z6 USING gist(geometry);
+
+
+-- For z7
+-- etldoc: osm_landuse_polygon ->  osm_residential_gen_z7
+DROP TABLE IF EXISTS osm_residential_gen_z7 CASCADE;
+CREATE TABLE osm_residential_gen_z7 AS
+(
+SELECT ST_SimplifyVW(geometry, power(zres(7), 2)) AS geometry
+FROM cluster_zres12_union
+WHERE ST_Area(geometry) > power(zres(6), 2)
+);
+CREATE INDEX ON osm_residential_gen_z7 USING gist(geometry);
+
+
+-- For z8
+-- etldoc: osm_landuse_polygon ->  osm_residential_gen_z8
+DROP TABLE IF EXISTS osm_residential_gen_z8 CASCADE;
+CREATE TABLE osm_residential_gen_z8 AS
+(
+SELECT ST_SimplifyVW(geometry, power(zres(8), 2)) AS geometry
+FROM cluster_zres12_union
+WHERE ST_Area(geometry) > power(zres(7), 2)
+);
+CREATE INDEX ON osm_residential_gen_z8 USING gist(geometry);
+
+
+-- For z9
+-- etldoc: osm_landuse_polygon ->  osm_residential_gen_z9
+DROP TABLE IF EXISTS osm_residential_gen_z9 CASCADE;
+CREATE TABLE osm_residential_gen_z9 AS
+(
+SELECT ST_SimplifyVW(geometry, power(zres(9), 2)) AS geometry
+FROM cluster_zres12_union
+WHERE ST_Area(geometry) > power(zres(9), 2)
+);
+CREATE INDEX ON osm_residential_gen_z9 USING gist(geometry);
+
+
+-- For z10
+-- etldoc: osm_landuse_polygon ->  osm_residential_gen_z10
+DROP TABLE IF EXISTS osm_residential_gen_z10 CASCADE;
+CREATE TABLE osm_residential_gen_z10 AS
+(
+SELECT ST_SimplifyVW(geometry, power(zres(10), 2)) AS geometry
+FROM cluster_zres14_union
+WHERE ST_Area(geometry) > power(zres(10), 2)
+);
+CREATE INDEX ON osm_residential_gen_z10 USING gist(geometry);
+
+
+-- For z11
+-- etldoc: osm_landuse_polygon ->  osm_residential_gen_z11
+DROP TABLE IF EXISTS osm_residential_gen_z11 CASCADE;
+CREATE TABLE osm_residential_gen_z11 AS
+(
+SELECT ST_SimplifyVW(geometry, power(zres(11), 2)) AS geometry
+FROM cluster_zres14_union
+WHERE ST_Area(geometry) > power(zres(11), 2)
+);
+CREATE INDEX ON osm_residential_gen_z11 USING gist(geometry);
+
+
+-- For z12
+-- etldoc: osm_landuse_polygon ->  osm_residential_gen_z12
+DROP TABLE IF EXISTS osm_residential_gen_z12 CASCADE;
+CREATE TABLE osm_residential_gen_z12 AS
+(
+SELECT ST_SimplifyVW(geometry, power(zres(12), 2)) AS geometry
+FROM cluster_zres14_union
+WHERE ST_Area(geometry) > power(zres(12), 2)
+);
+CREATE INDEX ON osm_residential_gen_z12 USING gist(geometry);