Move highway and railway into transportation

layers/transportation_name/merge_highways.sql

@@ -0,0 +1,57 @@
+-- Instead of using relations to find out the road names we
+-- stitch together the touching ways with the same name
+-- to allow for nice label rendering
+-- Because this works well for roads that do not have relations as well
+
+-- etldoc: osm_transportation_linestring ->  osm_transportation_name_linestring
+CREATE TABLE IF NOT EXISTS osm_transportation_name_linestring AS (
+	SELECT
+		(ST_Dump(geometry)).geom AS geometry,
+        -- NOTE: The osm_id is no longer the original one which can make it difficult
+        -- to lookup road names by OSM ID
+		member_osm_ids[0] AS osm_id,
+		member_osm_ids,
+		name,
+        ref,
+		highway,
+		z_order
+	FROM (
+		SELECT
+			ST_LineMerge(ST_Union(geometry)) AS geometry,
+			name,
+            ref,
+			highway,
+			min(z_order) AS z_order,
+			array_agg(DISTINCT osm_id) AS member_osm_ids
+	    FROM osm_transportation_linestring
+        -- We only care about highways (not railways) for labeling
+	    WHERE (name <> '' OR ref <> '') AND NULLIF(highway, '') IS NOT NULL
+	    GROUP BY name, highway, ref
+	) AS highway_union
+);
+
+CREATE INDEX IF NOT EXISTS osm_transportation_name_linestring_geometry_idx ON osm_transportation_name_linestring USING gist(geometry);
+
+-- etldoc: osm_transportation_name_linestring -> osm_transportation_name_linestring_gen1
+CREATE TABLE IF NOT EXISTS osm_transportation_name_linestring_gen1 AS (
+    SELECT ST_Simplify(geometry, 50) AS geometry, osm_id, member_osm_ids, name, ref, highway, z_order
+    FROM osm_transportation_name_linestring
+    WHERE highway IN ('motorway','trunk')  AND ST_Length(geometry) > 8000
+);
+CREATE INDEX IF NOT EXISTS osm_transportation_name_linestring_gen1_geometry_idx ON osm_transportation_name_linestring_gen1 USING gist(geometry);
+
+-- etldoc: osm_transportation_name_linestring_gen1 -> osm_transportation_name_linestring_gen2
+CREATE TABLE IF NOT EXISTS osm_transportation_name_linestring_gen2 AS (
+    SELECT ST_Simplify(geometry, 120) AS geometry, osm_id, member_osm_ids, name, ref, highway, z_order
+    FROM osm_transportation_name_linestring_gen1
+    WHERE highway IN ('motorway','trunk')  AND ST_Length(geometry) > 14000
+);
+CREATE INDEX IF NOT EXISTS osm_transportation_name_linestring_gen2_geometry_idx ON osm_transportation_name_linestring_gen2 USING gist(geometry);
+
+-- etldoc: osm_transportation_name_linestring_gen2 -> osm_transportation_name_linestring_gen3
+CREATE TABLE IF NOT EXISTS osm_transportation_name_linestring_gen3 AS (
+    SELECT ST_Simplify(geometry, 120) AS geometry, osm_id, member_osm_ids, name, ref, highway, z_order
+    FROM osm_transportation_name_linestring_gen2
+    WHERE highway = 'motorway' AND ST_Length(geometry) > 20000
+);
+CREATE INDEX IF NOT EXISTS osm_transportation_name_linestring_gen3_geometry_idx ON osm_transportation_name_linestring_gen3 USING gist(geometry);