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--
-- simplify.sql
--
-- You can use this to simplify coastline polygons if needed.
-- It will only work properly if polygons are not split and
-- the 3857 projection is used (ie if osmcoastline was run with
-- "-m 0 -s 3857").
--
CREATE TABLE simplified_land_polygons (
OGC_FID INTEGER PRIMARY KEY
);
SELECT AddGeometryColumn('simplified_land_polygons', 'GEOMETRY', 3857, 'POLYGON', 'XY', 1);
-- Depending on the detail you need you might have to change the numbers here.
-- The given numbers work up to about zoom level 9.
INSERT INTO simplified_land_polygons (ogc_fid, geometry) SELECT ogc_fid, SimplifyPreserveTopology(geometry, 300) FROM land_polygons WHERE ST_Area(geometry) > 300000;
SELECT CreateSpatialIndex('simplified_land_polygons', 'GEOMETRY');
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