Add drafted SQL queries with notes to work into docs

Author: rustprooflabs

docs/src/static/pgrouting-4-examples-initial-draft.sql

@@ -0,0 +1,244 @@
+SELECT *
+    FROM osm.pgosm_flex
+;
+
+
+CREATE EXTENSION IF NOT EXISTS pgrouting;
+CREATE SCHEMA IF NOT EXISTS routing;
+
+
+SELECT postgis_full_version(), pgr_version();
+
+
+
+CREATE TABLE routing.road_line AS
+WITH a AS (
+-- Remove as many multi-linestrings as possible with ST_LineMerge() 
+SELECT osm_id, osm_type, maxspeed, oneway, layer,
+        route_foot, route_cycle, route_motor, access,
+        ST_LineMerge(geom) AS geom
+    FROM osm.road_line
+), extra_cleanup AS (
+-- Pull out those that are still multi, use ST_Dump() to pull out parts
+SELECT osm_id, osm_type, maxspeed, oneway, layer,
+        route_foot, route_cycle, route_motor, access,
+        (ST_Dump(geom)).geom AS geom
+    FROM a 
+    WHERE ST_GeometryType(geom) = 'ST_MultiLineString'
+), combined AS (
+-- Combine two sources
+SELECT osm_id, osm_type, maxspeed, oneway, layer,
+        route_foot, route_cycle, route_motor, access,
+        geom
+    FROM a
+    WHERE ST_GeometryType(geom) != 'ST_MultiLineString'
+UNION
+SELECT osm_id, osm_type, maxspeed, oneway, layer,
+        route_foot, route_cycle, route_motor, access,
+        geom
+    FROM extra_cleanup
+    -- Some data may be lost here if multi-linestring somehow
+    -- persists through the extra_cleanup query
+    WHERE ST_GeometryType(geom) != 'ST_MultiLineString'
+)
+-- Calculate a new surrogate ID for key
+SELECT ROW_NUMBER() OVER (ORDER BY geom) AS id, *
+    FROM combined
+    ORDER BY geom
+;
+
+
+
+COMMENT ON COLUMN routing.road_line.id IS 'Surrogate ID, cannot rely on osm_id being unique after converting multi-linestrings to linestrings.';
+ALTER TABLE routing.road_line
+    ADD CONSTRAINT pk_routing_road_line PRIMARY KEY (id)
+;
+CREATE INDEX ix_routing_road_line_osm_id
+    ON routing.road_line (osm_id)
+;
+
+
+SELECT COUNT(*) FROM routing.road_line WHERE route_motor
+
+
+--SELECT pgr_nodeNetwork('routing.road_line', 0.1, 'id', 'geom');
+/*
+ * Seperate Crossing splits at intersections with actual crossings where both lines
+ * extend to the other side.
+ * It does NOT split long lines at intersections where one section extends past
+ * another section.  AKA - T-Intersections. 
+ * Unless Routing functions have become more flexible, this will NOT work with
+ * most common traffic routing use cases.
+ * 
+ * The ID comes through the new table with a new sub_id value.
+ * Only creates records where splitting was done.
+ * 
+ * Fort Collins sub-region took ~30 seconds
+ */
+DROP TABLE IF EXISTS routing.road_separate_crossing;
+--started at 8:20:30
+CREATE TABLE routing.road_separate_crossing AS
+SELECT *
+FROM pgr_separateCrossing('SELECT id, geom FROM routing.road_line WHERE route_motor', dryrun => false)
+;
+
+/*
+ * Takes much longer than pgr_separateCrossing
+ * 
+ * Seperate Crossing splits at touch points where two lines intersect
+ * This DOES split long lines at intersections where one section intersects another
+ * in the middle, AKA t-intesections
+ * 
+ * The ID comes through the new table with a new sub_id value.
+ * Only creates records where splitting was done. Will need to merge with
+ * unsplit lines from source table.
+ * 
+ * Fort Collins sub-region took 9 minutes (25k inputs, 21k outputs)
+ * 
+ * NOTE: Only seq, id, sub_id, and geom columns make it to final table. Does not help
+ * to pass in SELECT * thinking you'll get all the columns in the final table.
+ * (I tried to be lazier in later steps)
+ */
+DROP TABLE IF EXISTS routing.road_separate_touching;
+CREATE TABLE routing.road_separate_touching AS
+SELECT *
+FROM pgr_separateTouching('SELECT id, geom FROM routing.road_line WHERE route_motor', dryrun => false)
+;
+
+
+
+SELECT * FROM routing.road_line
+;
+SELECT * FROM routing.road_separate_touching
+;
+
+DROP TABLE IF EXISTS routing.road_motor_edges;
+CREATE TABLE routing.road_motor_edges AS
+WITH split_lines AS (
+SELECT r.id AS parent_id, spl.sub_id, r.osm_id, r.osm_type, r.maxspeed, r.oneway, r.layer
+        , r.access, spl.geom
+    FROM routing.road_line r
+    INNER JOIN routing.road_separate_touching spl
+        ON r.id = spl.id
+    WHERE route_motor
+), unsplit_lines AS (
+SELECT r.id AS parent_id, 1::INT AS sub_id, r.osm_id, r.osm_type, r.maxspeed, r.oneway, r.layer
+        , r.access, r.geom
+    FROM routing.road_line r
+    LEFT JOIN routing.road_separate_touching spl
+        ON r.id = spl.id
+    WHERE spl.id IS NULL
+        AND r.route_motor
+)
+SELECT *
+    FROM split_lines
+UNION
+SELECT *
+    FROM unsplit_lines
+;
+
+COMMENT ON TABLE routing.road_motor_edges IS 'OSM road data setup for edges for routing for motorized travel';
+ALTER TABLE routing.road_motor_edges
+    ADD edge_id BIGINT NOT NULL GENERATED ALWAYS AS IDENTITY PRIMARY KEY;
+ALTER TABLE routing.road_motor_edges
+    ADD source BIGINT;
+ALTER TABLE routing.road_motor_edges
+    ADD target BIGINT;
+;
+ALTER TABLE routing.road_motor_edges
+    ADD CONSTRAINT uq_routing_road_motor_edges_parent_id_sub_id
+    UNIQUE (parent_id, sub_id)
+;
+
+
+-----------------------------------------------------------------------
+-- SELECT pgr_createTopology('routing.road_line_noded', 0.1, 'geom');
+-----------------------------------------------------------------------
+DROP TABLE IF EXISTS routing.road_motor_vertices;
+CREATE TABLE routing.road_motor_vertices AS
+SELECT  * FROM pgr_extractVertices(
+  'SELECT edge_id AS id, geom FROM routing.road_motor_edges')
+;
+
+
+
+
+SELECT * 
+FROM routing.road_motor_vertices
+WHERE in_edges IS NOT NULL
+    OR out_edges IS NOT NULL
+;
+
+
+
+-------------------------------------------------
+--SELECT pgr_analyzeGraph('routing.road_line_noded', 0.1, 'geom');
+
+--  Update source column from out_edges
+
+WITH outgoing AS (
+    SELECT id AS source
+        , unnest(out_edges) AS edge_id
+        --, x, y
+  FROM routing.road_motor_vertices
+)
+UPDATE routing.road_motor_edges e
+SET source = o.source--, x1 = x, y1 = y
+FROM outgoing o
+WHERE e.edge_id = o.edge_id
+    AND e.source IS NULL
+;
+
+-- Update target colum from in_edges
+WITH incoming AS (
+    SELECT id AS target
+        , unnest(in_edges) AS edge_id
+        --, x, y
+  FROM routing.road_motor_vertices
+)
+UPDATE routing.road_motor_edges e
+SET target = i.target--, x1 = x, y1 = y
+FROM incoming i
+WHERE e.edge_id = i.edge_id
+    AND e.target IS NULL
+;
+
+
+SELECT *
+    FROM routing.road_motor_edges
+;
+
+
+
+---------------------- 
+-- TRYING TO CONTINUE HERE!
+ALTER TABLE routing.road_motor_edges
+    ADD cost_length DOUBLE PRECISION NOT NULL
+    GENERATED ALWAYS AS (ST_Length(geom))
+    STORED;
+
+
+/*
+ * v_start: 12181
+*  v_end: 10402
+ */
+
+
+SELECT * FROM routing.road_motor_edges;
+SELECT * FROM routing.road_motor_vertices;
+
+
+SELECT d.*, n.geom AS node_geom, e.geom AS edge_geom
+    FROM pgr_dijkstra(
+        'SELECT edge_id AS id, source, target, cost_length AS cost,
+                geom
+            FROM routing.road_motor_edges
+            ',
+            :start_id, :end_id, directed := False
+        ) d
+    INNER JOIN routing.road_motor_vertices n ON d.node = n.id
+    LEFT JOIN routing.road_motor_edges e ON d.edge = e.edge_id
+;
+
+
+