This topic describes the ST_Relate function. This function checks whether two geometry objects are spatially related. For example, this function checks whether two geometry objects intersect or whether one geometry object is included in the other.

Syntax

boolean  ST_Relate(geometry  geomA , geometry  geomB , text  intersectionMatrixPattern);
text  ST_Relate(geometry  geomA , geometry  geomB);
text  ST_Relate(geometry  geomA , geometry  geomB , integer  boundaryNodeRule);

Parameters

Parameter Description
geomA The first geometry object that you want to specify.
geomB The second geometry object that you want to specify.
intersectionMatrixPattern The DE-9IM matrix pattern that you want to specify.
boundaryNodeRule The boundary node rule that you want to specify.

Description

  • Version 1: This function checks whether the geometry objects that you specify spatially intersect at their interior rings, boundaries, or exterior rings in compliance with the DE-9IM matrix pattern that you define. If all the specified conditions are met, this function returns True. Otherwise, this function returns False.
    • This usage is suitable especially when you need to test compound checks of road intersections or crosses in one step.
    • This function does not support GeometryCollection objects.
  • Version 2: This function returns the DE-9IM matrices of the geometry objects that you specify. This function does not support GeometryCollection objects.
  • Version 3: Version 3 is similar to version 2, except that version 3 allows you to define a boundary node rule.
    • 1: OGC/MOD2
    • 2: Endpoint
    • 3: MultivalentEndpoint
    • 4: MonovalentEndpoint

Examples

  • Version 1:
    SELECT ST_Relate('LINESTRING(0 0,0 1)'::geometry, 'LINESTRING(0 0,1 1)'::geometry,'FF1F00102');
 st_relate
-----------
 t
(1 row)
  • Version 2:
    SELECT ST_Relate('LINESTRING(0 0,0 1)'::geometry, 'LINESTRING(0 0,1 1)'::geometry);
 st_relate
-----------
 FF1F00102
(1 row)