Move to new modular layer structure

layers/road/road.sql

@@ -0,0 +1,129 @@
+CREATE OR REPLACE FUNCTION ne_road_class(type VARCHAR) RETURNS VARCHAR AS $$
+  SELECT CASE type
+    WHEN 'Major Highway' THEN 'motorway'
+    WHEN 'Secondary Highway' THEN 'trunk'
+    WHEN 'Road' THEN 'primary'
+    ELSE type
+  END;
+$$ LANGUAGE SQL IMMUTABLE;
+
+CREATE TABLE IF NOT EXISTS ne_10m_global_roads AS (
+    SELECT geom, scalerank, ne_road_class(type) AS class
+    FROM ne_10m_roads
+    WHERE continent <> 'North America'
+      AND featurecla = 'Road'
+      AND type IN ('Major Highway', 'Secondary Highway', 'Road')
+    UNION ALL
+    SELECT geom, scalerank, ne_road_class(type) AS class
+    FROM ne_10m_roads_north_america
+    WHERE type IN ('Major Highway', 'Secondary Highway', 'Road')
+);
+
+CREATE INDEX IF NOT EXISTS ne_10m_global_roads_geom_idx ON ne_10m_global_roads USING gist(geom);
+CREATE INDEX IF NOT EXISTS ne_10m_global_roads_scalerank_idx ON ne_10m_global_roads(scalerank);
+
+CREATE OR REPLACE VIEW road_z4 AS (
+    SELECT geom, class
+    FROM ne_10m_global_roads
+    WHERE scalerank <= 5
+);
+
+CREATE OR REPLACE VIEW road_z5 AS (
+    SELECT geom, class
+    FROM ne_10m_global_roads
+    WHERE scalerank <= 6
+);
+
+CREATE OR REPLACE VIEW road_z6 AS (
+    SELECT geom, class
+    FROM ne_10m_global_roads
+    WHERE scalerank <= 7
+);
+
+CREATE OR REPLACE VIEW road_z7 AS (
+    SELECT geom, class
+    FROM ne_10m_global_roads
+    WHERE scalerank <= 7
+);
+
+CREATE TABLE IF NOT EXISTS road_z8 AS (
+    SELECT ST_Simplify(way, 200) AS geom, class::text
+    FROM roads
+    WHERE class IN ('motorway','trunk')
+);
+CREATE INDEX IF NOT EXISTS road_z8_geom_idx ON road_z8 USING gist(geom);
+
+CREATE TABLE IF NOT EXISTS road_z9 AS (
+    SELECT ST_Simplify(way, 120) AS geom, class::text
+    FROM roads
+    WHERE class IN ('motorway','trunk', 'primary')
+);
+CREATE INDEX IF NOT EXISTS road_z9_geom_idx ON road_z9 USING gist(geom);
+
+CREATE TABLE IF NOT EXISTS road_z10 AS (
+    SELECT ST_Simplify(way, 50) AS geom, class::text
+    FROM roads
+    WHERE class IN ('motorway','trunk', 'primary', 'secondary')
+);
+CREATE INDEX IF NOT EXISTS road_z10_geom_idx ON road_z10 USING gist(geom);
+
+CREATE TABLE IF NOT EXISTS road_z11 AS (
+    SELECT ST_Simplify(way, 20) AS geom, class::text
+    FROM roads
+    WHERE class IN ('motorway','trunk', 'primary', 'secondary', 'tertiary')
+);
+CREATE INDEX IF NOT EXISTS road_z11_geom_idx ON road_z11 USING gist(geom);
+
+CREATE OR REPLACE VIEW road_z12 AS (
+    SELECT way AS geom, class::text
+    FROM roads
+    WHERE class IN ('motorway','trunk','primary', 'secondary', 'tertiary', 'minor')
+    UNION ALL
+    SELECT way AS geom, class::text
+    FROM road_areas
+);
+
+CREATE OR REPLACE VIEW road_z13 AS (
+    SELECT way AS geom, class::text
+    FROM roads
+    WHERE class NOT IN ('path')
+    UNION ALL
+    SELECT way AS geom, class::text
+    FROM road_areas
+);
+
+CREATE OR REPLACE VIEW road_z14 AS (
+    SELECT way AS geom, class::text
+    FROM roads
+    UNION ALL
+    SELECT way AS geom, class::text
+    FROM road_areas
+);
+
+CREATE OR REPLACE FUNCTION layer_road(bbox geometry, zoom_level int)
+RETURNS TABLE(geom geometry, class text) AS $$
+    SELECT geom, class::text FROM (
+        SELECT * FROM road_z4 WHERE zoom_level BETWEEN 4 AND 5
+        UNION ALL
+        SELECT * FROM road_z5 WHERE zoom_level = 5
+        UNION ALL
+        SELECT * FROM road_z6 WHERE zoom_level = 6
+        UNION ALL
+        SELECT * FROM road_z7 WHERE zoom_level = 7
+        UNION ALL
+        SELECT * FROM road_z8 WHERE zoom_level = 8
+        UNION ALL
+        SELECT geom, class FROM road_z9 WHERE zoom_level = 9
+        UNION ALL
+        SELECT geom, class FROM road_z10 WHERE zoom_level = 10
+        UNION ALL
+        SELECT geom, class FROM road_z11 WHERE zoom_level = 11
+        UNION ALL
+        SELECT geom, class FROM road_z12 WHERE zoom_level = 12
+        UNION ALL
+        SELECT * FROM road_z13 WHERE zoom_level = 13
+        UNION ALL
+        SELECT * FROM road_z14 WHERE zoom_level >= 14
+    ) AS zoom_levels
+    WHERE geom && bbox;
+$$ LANGUAGE SQL IMMUTABLE;