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ST_Overlaps

Tests whether two geometries overlap - sharing some but not all interior points.

Syntax​

ST_Overlaps(geometry_a, geometry_b)

Parameters​

ParameterTypeDescription
geometry_aGeometryFirst geometry
geometry_bGeometrySecond geometry

Returns​

TypeDescription
BooleanTrue if geometries overlap, false otherwise

Examples​

Test Overlapping Polygons​

SELECT ST_Overlaps(
    ST_GeomFromText('POLYGON((0 0, 3 0, 3 3, 0 3, 0 0))'),
    ST_GeomFromText('POLYGON((2 2, 5 2, 5 5, 2 5, 2 2))')
);
-- Returns: true

Find Overlapping Parcels​

SELECT a.id as parcel_a, b.id as parcel_b
FROM parcels a, parcels b
WHERE a.id < b.id
  AND ST_Overlaps(a.geom, b.geom);

Detect Data Quality Issues​

SELECT COUNT(*) as overlap_count
FROM buildings a, buildings b
WHERE a.id < b.id
  AND ST_Overlaps(a.geom, b.geom);

Notes​

  • Overlaps means geometries share some but not all points
  • Both geometries must be of the same dimension (polygon/polygon or line/line)
  • Returns false if one geometry contains the other entirely
  • Returns false for point/polygon or line/polygon comparisons
  • Use ST_Intersects for general intersection tests

See Also​