31 lines
1.4 KiB
PL/PgSQL
31 lines
1.4 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, class city_class, "rank" int) AS $$
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SELECT osm_id, geometry, name, name_en, place, "rank"
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FROM osm_city_point
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WHERE geometry && bbox
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AND ((zoom_level = 2 AND "rank" = 1)
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OR (zoom_level BETWEEN 3 AND 7 AND "rank" <= zoom_level)
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)
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UNION ALL
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SELECT osm_id, geometry, name, name_en, place, COALESCE("rank", gridrank + 10) FROM (
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SELECT osm_id, geometry, name, name_en, place, "rank",
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row_number() OVER (
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PARTITION BY LabelGrid(geometry, 150 * pixel_width)
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ORDER BY "rank" ASC NULLS LAST,
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place ASC NULLS LAST,
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population DESC NULLS LAST,
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length(name) ASC
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)::int AS gridrank
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FROM osm_city_point
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WHERE geometry && bbox
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AND ((zoom_level BETWEEN 8 AND 9 AND place <= 'town'::city_class)
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OR (zoom_level = 10 AND place <= 'village'::city_class)
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OR (zoom_level BETWEEN 11 AND 13 AND place <= 'suburb'::city_class)
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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 OR "rank" IS NOT NULL))
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OR (zoom_level BETWEEN 9 AND 12 AND (gridrank <= 9 OR "rank" IS NOT NULL))
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OR (zoom_level >= 13);
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$$ LANGUAGE SQL IMMUTABLE;
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