openmaptiles/layers/transportation/update_transportation_merge.sql

DROP MATERIALIZED VIEW IF EXISTS osm_transportation_merge_linestring CASCADE;
DROP MATERIALIZED VIEW IF EXISTS osm_transportation_merge_linestring_gen3 CASCADE;
DROP MATERIALIZED VIEW IF EXISTS osm_transportation_merge_linestring_gen4 CASCADE;
DROP MATERIALIZED VIEW IF EXISTS osm_transportation_merge_linestring_gen5 CASCADE;
DROP MATERIALIZED VIEW IF EXISTS osm_transportation_merge_linestring_gen6 CASCADE;
DROP MATERIALIZED VIEW IF EXISTS osm_transportation_merge_linestring_gen7 CASCADE;


DROP TRIGGER IF EXISTS trigger_flag_transportation ON osm_highway_linestring;
DROP TRIGGER IF EXISTS trigger_refresh ON transportation.updates;

-- 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


-- Improve performance of the sql in transportation_name/network_type.sql
CREATE INDEX IF NOT EXISTS osm_highway_linestring_highway_idx
  ON osm_highway_linestring(highway);

-- Improve performance of the sql below
CREATE INDEX IF NOT EXISTS osm_highway_linestring_highway_partial_idx
  ON osm_highway_linestring(highway)
  WHERE highway IN ('motorway','trunk', 'primary');

  -- etldoc: osm_highway_linestring ->  osm_transportation_merge_linestring
CREATE MATERIALIZED VIEW osm_transportation_merge_linestring AS (
    SELECT
        (ST_Dump(geometry)).geom AS geometry,
        NULL::bigint AS osm_id,
        highway,
        z_order
    FROM (
      SELECT
          ST_LineMerge(ST_Collect(geometry)) AS geometry,
          highway,
          min(z_order) AS z_order
      FROM osm_highway_linestring
      WHERE highway IN ('motorway','trunk', 'primary') AND ST_IsValid(geometry)
      group by highway
    ) AS highway_union
);
CREATE INDEX IF NOT EXISTS osm_transportation_merge_linestring_geometry_idx
  ON osm_transportation_merge_linestring USING gist(geometry);
CREATE INDEX IF NOT EXISTS osm_transportation_merge_linestring_highway_partial_idx
  ON osm_transportation_merge_linestring(highway)
  WHERE highway IN ('motorway','trunk', 'primary');

-- etldoc: osm_transportation_merge_linestring -> osm_transportation_merge_linestring_gen3
CREATE MATERIALIZED VIEW osm_transportation_merge_linestring_gen3 AS (
    SELECT ST_Simplify(geometry, 120) AS geometry, osm_id, highway, z_order
    FROM osm_transportation_merge_linestring
    WHERE highway IN ('motorway','trunk', 'primary')
);
CREATE INDEX IF NOT EXISTS osm_transportation_merge_linestring_gen3_geometry_idx
  ON osm_transportation_merge_linestring_gen3 USING gist(geometry);
CREATE INDEX IF NOT EXISTS osm_transportation_merge_linestring_gen3_highway_partial_idx
  ON osm_transportation_merge_linestring_gen3(highway)
  WHERE highway IN ('motorway','trunk', 'primary');

-- etldoc: osm_transportation_merge_linestring_gen3 -> osm_transportation_merge_linestring_gen4
CREATE MATERIALIZED VIEW osm_transportation_merge_linestring_gen4 AS (
    SELECT ST_Simplify(geometry, 200) AS geometry, osm_id, highway, z_order
    FROM osm_transportation_merge_linestring_gen3
    WHERE highway IN ('motorway','trunk', 'primary') AND ST_Length(geometry) > 50
);
CREATE INDEX IF NOT EXISTS osm_transportation_merge_linestring_gen4_geometry_idx
  ON osm_transportation_merge_linestring_gen4 USING gist(geometry);
CREATE INDEX IF NOT EXISTS osm_transportation_merge_linestring_gen4_highway_partial_idx
  ON osm_transportation_merge_linestring_gen4(highway)
  WHERE highway IN ('motorway','trunk', 'primary');

-- etldoc: osm_transportation_merge_linestring_gen4 -> osm_transportation_merge_linestring_gen5
CREATE MATERIALIZED VIEW osm_transportation_merge_linestring_gen5 AS (
    SELECT ST_Simplify(geometry, 500) AS geometry, osm_id, highway, z_order
    FROM osm_transportation_merge_linestring_gen4
    WHERE highway IN ('motorway','trunk') AND ST_Length(geometry) > 100
);
CREATE INDEX IF NOT EXISTS osm_transportation_merge_linestring_gen5_geometry_idx
  ON osm_transportation_merge_linestring_gen5 USING gist(geometry);
CREATE INDEX IF NOT EXISTS osm_transportation_merge_linestring_gen5_highway_partial_idx
  ON osm_transportation_merge_linestring_gen5(highway)
  WHERE highway IN ('motorway', 'trunk');

-- etldoc: osm_transportation_merge_linestring_gen5 -> osm_transportation_merge_linestring_gen6
CREATE MATERIALIZED VIEW osm_transportation_merge_linestring_gen6 AS (
    SELECT ST_Simplify(geometry, 1000) AS geometry, osm_id, highway, z_order
    FROM osm_transportation_merge_linestring_gen5
    WHERE highway IN ('motorway','trunk') AND ST_Length(geometry) > 500
);
CREATE INDEX IF NOT EXISTS osm_transportation_merge_linestring_gen6_geometry_idx
  ON osm_transportation_merge_linestring_gen6 USING gist(geometry);
CREATE INDEX IF NOT EXISTS osm_transportation_merge_linestring_gen6_highway_partial_idx
  ON osm_transportation_merge_linestring_gen6(highway)
  WHERE highway IN ('motorway','trunk');

-- etldoc: osm_transportation_merge_linestring_gen6 -> osm_transportation_merge_linestring_gen7
CREATE MATERIALIZED VIEW osm_transportation_merge_linestring_gen7 AS (
    SELECT ST_Simplify(geometry, 2000) AS geometry, osm_id, highway, z_order
    FROM osm_transportation_merge_linestring_gen6
    WHERE highway IN ('motorway') AND ST_Length(geometry) > 1000
);
CREATE INDEX IF NOT EXISTS osm_transportation_merge_linestring_gen7_geometry_idx
  ON osm_transportation_merge_linestring_gen7 USING gist(geometry);


-- Handle updates

CREATE SCHEMA IF NOT EXISTS transportation;

CREATE TABLE IF NOT EXISTS transportation.updates(id serial primary key, t text, unique (t));
CREATE OR REPLACE FUNCTION transportation.flag() RETURNS trigger AS $$
BEGIN
    INSERT INTO transportation.updates(t) VALUES ('y')  ON CONFLICT(t) DO NOTHING;
    RETURN null;
END;
$$ language plpgsql;

CREATE OR REPLACE FUNCTION transportation.refresh() RETURNS trigger AS
  $BODY$
  BEGIN
    RAISE NOTICE 'Refresh transportation';
    REFRESH MATERIALIZED VIEW osm_transportation_merge_linestring;
    REFRESH MATERIALIZED VIEW osm_transportation_merge_linestring_gen3;
    REFRESH MATERIALIZED VIEW osm_transportation_merge_linestring_gen4;
    REFRESH MATERIALIZED VIEW osm_transportation_merge_linestring_gen5;
    REFRESH MATERIALIZED VIEW osm_transportation_merge_linestring_gen6;
    REFRESH MATERIALIZED VIEW osm_transportation_merge_linestring_gen7;
    DELETE FROM transportation.updates;
    RETURN null;
  END;
  $BODY$
language plpgsql;

CREATE TRIGGER trigger_flag_transportation
    AFTER INSERT OR UPDATE OR DELETE ON osm_highway_linestring
    FOR EACH STATEMENT
    EXECUTE PROCEDURE transportation.flag();

CREATE CONSTRAINT TRIGGER trigger_refresh
    AFTER INSERT ON transportation.updates
    INITIALLY DEFERRED
    FOR EACH ROW
    EXECUTE PROCEDURE transportation.refresh();