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ST_Area

Calculates the Cartesian area of a geometry.

Syntax​

ST_Area(geometry)

Parameters​

ParameterTypeDescription
geometryGeometryInput geometry (polygon or multipolygon)

Returns​

TypeDescription
Float64Area of the geometry

Examples​

Area of a Square​

SELECT ST_Area(ST_GeomFromText('POLYGON((0 0, 4 0, 4 4, 0 4, 0 0))'));
-- Returns: 16.0

Area of Polygon with Hole​

SELECT ST_Area(ST_GeomFromText(
    'POLYGON((0 0, 10 0, 10 10, 0 10, 0 0), (2 2, 8 2, 8 8, 2 8, 2 2))'
));
-- Returns: 64.0 (100 - 36)

Calculate Total Area by Category​

SELECT category, SUM(ST_Area(geom)) as total_area
FROM parcels
GROUP BY category;

Filter Large Polygons​

SELECT * FROM buildings
WHERE ST_Area(geom) > 1000;

Notes​

  • Returns 0 for Points and LineStrings
  • For MultiPolygons, returns the sum of all polygon areas
  • Area is in squared units of the input geometry coordinates
  • For geographic coordinates, the result is in square degrees (not square meters)
  • Polygons with holes subtract the hole area from the outer ring

See Also​