ST_Intersection

Calculates the set of points shared by two GEOMETRY objects.

Calculates the set of points shared by two GEOMETRY objects.

Behavior type

Immutable

Syntax

ST_Intersection( g1, g2 )

Arguments

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

Returns

GEOMETRY

Supported data types

Data Type GEOMETRY
Point Yes
Multipoint Yes
Linestring Yes
Multilinestring Yes
Polygon Yes
Multipolygon Yes
GeometryCollection Yes

Examples

The following examples show how to use ST_Intersection.

Two polygons intersect at a single point:

=> SELECT ST_AsText(ST_Intersection(ST_GeomFromText('POLYGON((0 2,1 1,0 -1,
   0 2))'),ST_GeomFromText('POLYGON((-1 2,0 0,-2 0,-1 2))')));
    ST_AsText
-----------------
 POINT(0 0)
(1 row)

Two polygons:

=> SELECT ST_AsText(ST_Intersection(ST_GeomFromText('POLYGON((1 2,1 5,4 5,
   4 2,1 2))'), ST_GeomFromText('POLYGON((3 1,3 3,5 3,5 1,3 1))')));
 ST_AsText
------------------
POLYGON ((4 3, 4 2, 3 2, 3 3, 4 3))
(1 row)

Two non-intersecting linestrings:

=> SELECT ST_AsText(ST_Intersection(ST_GeomFromText('LINESTRING(1 1,1 3,3 3)'),
   ST_GeomFromText('LINESTRING(1 5,1 7,-1 7)')));
        ST_AsText
--------------------------
 GEOMETRYCOLLECTION EMPTY
(1 row)