ST_Relate(ST_Geometry) method for type ST

ST_Relate(ST_Geometry) method for type ST_Geometry

Determines how a geometry value is spatially related to another geometry value by returning an intersection matrix. The ST_Relate method returns a 9-character string from the Dimensionally Extended 9 Intersection Model (DE-9IM) to describe the pair-wise relationship between two spatial data items. For example, the ST_Relate method determines if an intersection occurs between the geometries, and the geometry of the resulting intersection, if it exists.

Syntax

geometry-expression.ST_Relate(geo2)

Parameters

Name	Type	Description
geo2	ST_Geometry	The second geometry value that is to be compared to the geometry-expression.

Returns

CHAR(9) Returns A 9-character string representing a matrix in the dimensionally-extended 9 intersection model. Each character in the 9-character string represents the type of intersection at one of the nine possible intersections between the interior, boundary, and exterior of the two geometries.

Remarks

Tests if a geometry value is spatially related to another geometry value by testing for intersection between the interior, boundary, and exterior of two geometries, as specified by the intersection matrix.

The intersection matrix is returned as a string. While it is possible to use this method variant to test a spatial relationship by examining the returned string, it is more efficient to test relationships by passing a pattern string as second parameter or by using specific spatial predicates such as ST_Contains or ST_Intersects. See also: How spatial relationships work.

Note

If the geometry-expression contains circularstrings, then these are interpolated to line strings.

Note

This method can not be used with geometries in round-Earth spatial reference system.

Standards and compatibility

Example

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