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cquest/point_density.sql

Created July 16, 2014 16:18
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osm2pgsql point density mapnik query
Raw
point_density.sql
(SELECT box, floor(10*log(count(*)+1)) AS nb
FROM planet_osm_point
JOIN
(SELECT ST_setSRID(ST_Makebox2D(ST_MakePoint(st_xmin(!bbox!)+x*!pixel_width!, st_ymin(!bbox!)+!pixel_height!*y),ST_MakePoint(st_xmin(!bbox!)+(x+1)*!pixel_width!,st_ymin(!bbox!)+!pixel_height!*(y+1))),900913) AS box
FROM
(SELECT generate_series(0,255) AS x) AS h,
(SELECT generate_series(0,255) AS y) AS v) AS b ON (way && b.box) group by b.box) AS density
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