ST_Relate(ST_Geometry,CHAR(9)) method for type ST

ST_Relate(ST_Geometry,CHAR(9)) method for type ST_Geometry

Tests if a geometry value is spatially related to another geometry value as specified by the intersection matrix. The ST_Relate method uses 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,relate-matrix)

Parameters

Name	Type	Description
geo2	ST_Geometry	The second geometry value that is to be compared to the geometry-expression.
relate-matrix	CHAR(9)	A 9-character string representing a matrix in the dimensionally-extended 9 intersection model. Each character defined in the 9-character string represents the type of intersection allowed at one of the nine possible intersections between the interior, boundary, and exterior of the two geometries.

Returns

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. 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

The following example returns a result with one row for each shape that has the '0F***T***' relationship with the specified line. The '0' means the interiors of both geometries must intersect and result in a point or multipoint. The 'F' means the interior of the line and the boundary of Shape must not intersect. The 'T' means the exterior of the line and the interior of the Shape must intersect.

SELECT ShapeID, "Description" From SpatialShapes
WHERE NEW ST_LineString( 'LineString( 0 0, 10 0 )' )
    .ST_Relate( Shape, '0F****T**' ) = 1
ORDER BY ShapeID

The example returns the following result set:

ShapeID	Description
`18`	`CircularString`
`30`	`Multicurve`

Discuss this page in DocCommentXchange.