Files
openmaptiles/layers/waterway/merge_waterway.sql
2017-01-04 16:59:42 -05:00

85 lines
3.2 KiB
PL/PgSQL

-- We merge the waterways by name like the highways
-- This helps to drop not important rivers (since they do not have a name)
-- and also makes it possible to filter out too short rivers
-- etldoc: osm_waterway_linestring -> osm_important_waterway_linestring
CREATE MATERIALIZED VIEW osm_important_waterway_linestring AS (
SELECT
(ST_Dump(geometry)).geom AS geometry,
name
FROM (
SELECT
ST_LineMerge(ST_Union(geometry)) AS geometry,
name
FROM osm_waterway_linestring
WHERE name <> '' AND waterway = 'river'
GROUP BY name
) AS waterway_union
) WITH NO DATA;
CREATE INDEX IF NOT EXISTS osm_important_waterway_linestring_geometry_idx ON osm_important_waterway_linestring USING gist(geometry);
-- etldoc: osm_important_waterway_linestring -> osm_important_waterway_linestring_gen1
CREATE MATERIALIZED VIEW osm_important_waterway_linestring_gen1 AS (
SELECT ST_Simplify(geometry, 60) AS geometry, name
FROM osm_important_waterway_linestring
WHERE ST_Length(geometry) > 1000
) WITH NO DATA;
CREATE INDEX IF NOT EXISTS osm_important_waterway_linestring_gen1_geometry_idx ON osm_important_waterway_linestring_gen1 USING gist(geometry);
-- etldoc: osm_important_waterway_linestring_gen1 -> osm_important_waterway_linestring_gen2
CREATE MATERIALIZED VIEW osm_important_waterway_linestring_gen2 AS (
SELECT ST_Simplify(geometry, 100) AS geometry, name
FROM osm_important_waterway_linestring_gen1
WHERE ST_Length(geometry) > 4000
) WITH NO DATA;
CREATE INDEX IF NOT EXISTS osm_important_waterway_linestring_gen2_geometry_idx ON osm_important_waterway_linestring_gen2 USING gist(geometry);
-- etldoc: osm_important_waterway_linestring_gen2 -> osm_important_waterway_linestring_gen3
CREATE MATERIALIZED VIEW osm_important_waterway_linestring_gen3 AS (
SELECT ST_Simplify(geometry, 200) AS geometry, name
FROM osm_important_waterway_linestring_gen2
WHERE ST_Length(geometry) > 8000
) WITH NO DATA;
CREATE INDEX IF NOT EXISTS osm_important_waterway_linestring_gen3_geometry_idx ON osm_important_waterway_linestring_gen3 USING gist(geometry);
-- Handle updates
CREATE SCHEMA waterway;
CREATE TABLE IF NOT EXISTS waterway.updates(id serial primary key, t text, unique (t));
CREATE OR REPLACE FUNCTION waterway.flag() RETURNS trigger AS $$
BEGIN
INSERT INTO waterway.updates(t) VALUES ('y') ON CONFLICT(t) DO NOTHING;
RETURN null;
END;
$$ language plpgsql;
CREATE OR REPLACE FUNCTION waterway.refresh() RETURNS trigger AS
$BODY$
BEGIN
RAISE LOG 'Refresh transportation_name';
REFRESH MATERIALIZED VIEW osm_important_waterway_linestring;
REFRESH MATERIALIZED VIEW osm_important_waterway_linestring_gen1;
REFRESH MATERIALIZED VIEW osm_important_waterway_linestring_gen2;
REFRESH MATERIALIZED VIEW osm_important_waterway_linestring_gen3;
DELETE FROM waterway.updates;
RETURN null;
END;
$BODY$
language plpgsql;
CREATE TRIGGER waterway.trigger_flag
AFTER INSERT OR UPDATE OR DELETE ON osm_waterway_linestring
FOR EACH STATEMENT
EXECUTE PROCEDURE waterway.flag();
CREATE CONSTRAINT TRIGGER waterway.trigger_refresh
AFTER INSERT ON waterway.updates
INITIALLY DEFERRED
FOR EACH ROW
EXECUTE PROCEDURE waterway.refresh();