ST_Relate

Determines if a given GEOMETRY object is spatially related to another GEOMETRY object, based on the specified DE-9IM pattern matrix string.

The DE-9IM standard identifies how two objects are spatially related to each other.

Behavior type

Syntax

ST_Relate( g1, g2, matrix )

Arguments

g1

Spatial object, type GEOMETRY

g2

Spatial object, type GEOMETRY

matrix

DE-9IM pattern matrix string, type CHAR(9). This string represents a 3 x 3 matrix of restrictions on the dimensions of the respective intersections of the interior, boundary, and exterior of the two geometries. Must contain exactly 9 of the following characters:

• T

• F

• 0

• 1

• 2

• *

Returns

BOOLEAN

Supported data types

Examples

The following examples show how to use ST_Relate.

The DE-9IM pattern for "equals" is 'T*F**FFF2':

=> SELECT ST_Relate(ST_GeomFromText('LINESTRING(0 1,2 2)'),
   ST_GeomFromText('LINESTRING(2 2,0 1)'), 'T*F**FFF2');
 ST_Relate
--------------
 t
(1 row)

The DE-9IM pattern for "overlaps" is 'T*T***T**':

=> SELECT ST_Relate(ST_GeomFromText('POLYGON((-1 -1,0 1,2 2,-1 -1))'),
   ST_GeomFromText('POLYGON((0 1,1 -1,1 1,0 1))'), 'T*T***T**');
 ST_Relate
-----------
 t
(1 row)