Filter (geometry Data Type)

A method that offers a fast, index-only intersection method to determine if a geometry instance intersects another geometry instance, assuming an index is available.

Returns 1 if a geometry instance potentially intersects another geometry instance. This method may produce a false positive return, and the exact result may be plan-dependent. Returns an accurate 0 value (true negative return) if there is no intersection of geometry instances found.

In cases where an index is not available, or is not used, the method will return the same values as STIntersects() when called with the same parameters.

.Filter ( other_geometry )




Is another geometry instance to compare against the instance on which Filter() is invoked.

SQL Server return type: bit

CLR return type: SqlBoolean

This method is not deterministic and is not precise.

The following example uses Filter() to determine if two geometry instances intersect each other.


CREATE TABLE sample (id int primary key, g geometry)
INSERT INTO sample values
   (0, geometry::Point(0, 0, 0)),
   (1, geometry::Point(0, 1, 0)),
   (2, geometry::Point(0, 2, 0)),
   (3, geometry::Point(0, 3, 0)),
   (4, geometry::Point(0, 4, 0))

CREATE SPATIAL INDEX sample_idx ON sample(g)
   bounding_box = (-8000, -8000, 8000, 8000)
FROM sample 
WHERE g.Filter(geometry::Parse(
   'POLYGON((-1 -1, 1 -1, 1 1, -1 1, -1 -1))')) = 1

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