b7429ce6f5
The ocean layer (table osm_ocean_polygon insert by `make import-data`) is made from squares that have a 10m buffer. This creates extra geometry in vector tiles as: Union of full ocean squares should decrease the size of the water layer. there are 8042 polygons (squares, 5 points, more then 100km<sup>2</sup>), which was reduced to 22 polygons - 1184kB vs 40kB respectively. In mbtiles should be the size reduction even more significant, due to the creation of more polygons based on a 10m buffer of each square.
103 lines
3.5 KiB
PL/PgSQL
103 lines
3.5 KiB
PL/PgSQL
-- Recreate ocean layer by union regular squares into larger polygons
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-- etldoc: osm_ocean_polygon -> osm_ocean_polygon_union
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CREATE TABLE IF NOT EXISTS osm_ocean_polygon_union AS
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(
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SELECT (ST_Dump(ST_Union(ST_MakeValid(geometry)))).geom::geometry(Polygon, 3857) AS geometry
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FROM osm_ocean_polygon
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--for union select just full square (not big triangles)
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WHERE ST_Area(geometry) > 100000000 AND
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ST_NPoints(geometry) = 5
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UNION ALL
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SELECT geometry
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FROM osm_ocean_polygon
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-- as 321 records have less then 5 coordinates (triangle)
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-- bigger then 5 coordinates have squares with holes from island and coastline
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WHERE ST_NPoints(geometry) <> 5
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);
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CREATE INDEX IF NOT EXISTS osm_ocean_polygon_union_geom_idx
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ON osm_ocean_polygon_union
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USING GIST (geometry);
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--Drop data from original table but keep table as `CREATE TABLE IF NOT EXISTS` still test if query is valid
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TRUNCATE TABLE osm_ocean_polygon;
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-- This statement can be deleted after the water importer image stops creating this object as a table
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DO
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$$
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BEGIN
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DROP TABLE IF EXISTS osm_ocean_polygon_gen1 CASCADE;
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EXCEPTION
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WHEN wrong_object_type THEN
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END;
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$$ LANGUAGE plpgsql;
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-- etldoc: osm_ocean_polygon_union -> osm_ocean_polygon_gen1
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DROP MATERIALIZED VIEW IF EXISTS osm_ocean_polygon_gen1 CASCADE;
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CREATE MATERIALIZED VIEW osm_ocean_polygon_gen1 AS
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(
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SELECT ST_Simplify(geometry, 20) AS geometry
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FROM osm_ocean_polygon_union
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) /* DELAY_MATERIALIZED_VIEW_CREATION */ ;
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CREATE INDEX IF NOT EXISTS osm_ocean_polygon_gen1_idx ON osm_ocean_polygon_gen1 USING gist (geometry);
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-- This statement can be deleted after the water importer image stops creating this object as a table
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DO
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$$
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BEGIN
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DROP TABLE IF EXISTS osm_ocean_polygon_gen2 CASCADE;
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EXCEPTION
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WHEN wrong_object_type THEN
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END;
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$$ LANGUAGE plpgsql;
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-- etldoc: osm_ocean_polygon_union -> osm_ocean_polygon_gen2
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DROP MATERIALIZED VIEW IF EXISTS osm_ocean_polygon_gen2 CASCADE;
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CREATE MATERIALIZED VIEW osm_ocean_polygon_gen2 AS
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(
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SELECT ST_Simplify(geometry, 40) AS geometry
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FROM osm_ocean_polygon_union
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) /* DELAY_MATERIALIZED_VIEW_CREATION */ ;
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CREATE INDEX IF NOT EXISTS osm_ocean_polygon_gen2_idx ON osm_ocean_polygon_gen2 USING gist (geometry);
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-- This statement can be deleted after the water importer image stops creating this object as a table
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DO
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$$
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BEGIN
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DROP TABLE IF EXISTS osm_ocean_polygon_gen3 CASCADE;
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EXCEPTION
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WHEN wrong_object_type THEN
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END;
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$$ LANGUAGE plpgsql;
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-- etldoc: osm_ocean_polygon_union -> osm_ocean_polygon_gen3
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DROP MATERIALIZED VIEW IF EXISTS osm_ocean_polygon_gen3 CASCADE;
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CREATE MATERIALIZED VIEW osm_ocean_polygon_gen3 AS
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(
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SELECT ST_Simplify(geometry, 80) AS geometry
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FROM osm_ocean_polygon_union
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) /* DELAY_MATERIALIZED_VIEW_CREATION */ ;
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CREATE INDEX IF NOT EXISTS osm_ocean_polygon_gen3_idx ON osm_ocean_polygon_gen3 USING gist (geometry);
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-- This statement can be deleted after the water importer image stops creating this object as a table
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DO
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$$
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BEGIN
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DROP TABLE IF EXISTS osm_ocean_polygon_gen4 CASCADE;
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EXCEPTION
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WHEN wrong_object_type THEN
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END;
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$$ LANGUAGE plpgsql;
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-- etldoc: osm_ocean_polygon_union -> osm_ocean_polygon_gen4
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DROP MATERIALIZED VIEW IF EXISTS osm_ocean_polygon_gen4 CASCADE;
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CREATE MATERIALIZED VIEW osm_ocean_polygon_gen4 AS
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(
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SELECT ST_Simplify(geometry, 160) AS geometry
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FROM osm_ocean_polygon_union
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) /* DELAY_MATERIALIZED_VIEW_CREATION */ ;
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CREATE INDEX IF NOT EXISTS osm_ocean_polygon_gen4_idx ON osm_ocean_polygon_gen4 USING gist (geometry);
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