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Faking building height by using polygon size

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Aandrewxhill
Last edited Dec 5, 2012
Created on Dec 5, 2012

This example visualizes building footprints from OpenStreetMap by faking height through polygon size rather than actual 3D extrusion. It shows how larger building footprints appear taller, using the SQL expression `st_area(the_geom_webmercator)/400` to compute a pseudo-height value from each polygon’s area. The code relies on PostGIS spatial functions (`st_area`, `the_geom_webmercator`) to transform the geometry and calculate the metric, then renders the result as a choropleth-like map where polygon size visually encodes the derived height. The data source is the `osm_export_polygon` table, and the approach emphasizes area-to-height mapping over true elevation data.

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