30 lines
1.3 KiB
PL/PgSQL
30 lines
1.3 KiB
PL/PgSQL
CREATE OR REPLACE FUNCTION layer_city(bbox geometry, zoom_level int, pixel_width numeric)
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RETURNS TABLE(osm_id bigint, geometry geometry, name text, name_en text, place text, scalerank int) AS $$
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SELECT osm_id, geometry, name, name_en, place::text, scalerank
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FROM osm_place_point
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WHERE geometry && bbox
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AND ((zoom_level = 2 AND scalerank = 0)
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OR (zoom_level BETWEEN 3 AND 7 AND scalerank < zoom_level)
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)
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UNION ALL
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SELECT osm_id, geometry, name, name_en, place::text, scalerank FROM (
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SELECT osm_id, geometry, name, name_en, place, scalerank,
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row_number() OVER (
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PARTITION BY LabelGrid(geometry, 150 * pixel_width)
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ORDER BY place::place_subclass ASC NULLS LAST,
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population DESC NULLS LAST,
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length(name) DESC
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) AS gridrank
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FROM osm_place_point
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WHERE geometry && bbox
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AND ((zoom_level BETWEEN 8 AND 9 AND place::place_subclass <= 'town'::place_subclass)
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OR (zoom_level = 10 AND place::place_subclass <= 'village'::place_subclass)
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OR (zoom_level BETWEEN 11 AND 13 AND place::place_subclass <= 'suburb'::place_subclass)
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OR (zoom_level >= 14)
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)
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) AS ranked_places
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WHERE (zoom_level = 8 AND gridrank <= 4)
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OR (zoom_level BETWEEN 9 AND 12 AND gridrank <= 9)
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OR (zoom_level >= 13);
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$$ LANGUAGE SQL IMMUTABLE;
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