ST_Intersects

Determines if two GEOMETRY or GEOGRAPHY objects intersect or touch at a single point.

Determines if two GEOMETRY or GEOGRAPHY objects intersect or touch at a single point. If ST_Disjoint returns TRUE, ST_Intersects returns FALSE for the same GEOMETRY or GEOGRAPHY objects.

GEOGRAPHY Polygons with a vertex or border on the International Date Line (IDL) or the North or South pole are not supported.

Behavior type

Immutable

Syntax

ST_Intersects( g1, g2
                  [USING PARAMETERS bbox={true | false}, spheroid={true | false}])

Arguments

g1: Spatial object, type GEOMETRY
g2: Spatial object, type GEOMETRY

Parameters

bbox = {true | false}

Boolean. Intersects the bounding box of g1 and g2.

Default: False

spheroid = {true | false}

(Optional) BOOLEAN that specifies whether to use a perfect sphere or WGS84.

Default: False

Returns

BOOLEAN

Supported data types

Data Type	GEOMETRY	GEOGRAPHY (WGS84)
Point	Yes	Yes
Multipoint	Yes	No
Linestring	Yes	No
Multilinestring	Yes	No
Polygon	Yes	Yes
Multipolygon	Yes	No
GeometryCollection	Yes	No

Compatible GEOGRAPHY pairs:

Data Type	GEOGRAPHY (WGS84)
Point-Point	No
Linestring-Point	No
Polygon-Point	Yes
Multipolygon-Point	No

Examples

The following examples show how to use ST_Intersects.

Two polygons do not intersect or touch:

=> SELECT ST_Intersects (ST_GeomFromText('POLYGON((-1 2,0 3,0 1,-1 2))'),
   ST_GeomFromText('POLYGON((1 0,1 1,2 2,1 0))'));
 ST_Intersects
--------------
 f
(1 row)

Two polygons touch at a single point:

=> SELECT ST_Intersects (ST_GeomFromText('POLYGON((-1 2,0 3,0 1,-1 2))'),
   ST_GeomFromText('POLYGON((1 0,1 1,0 1,1 0))'));
 ST_Intersects
--------------
 t
(1 row)

Two polygons intersect:

=> SELECT ST_Intersects (ST_GeomFromText('POLYGON((-1 2, 0 3, 0 1, -1 2))'),
   ST_GeomFromText('POLYGON((0 2, -1 3, -2 0, 0 2))'));
 ST_Intersects
--------------
 t
(1 row)