geometry-expression.ST_CoversFilter(geo2)

The ST_CoversFilter method provides an efficient test to determine if one geometry might cover the other. Returns 1 if the geometry-expression might cover geo2, otherwise 0.

This test is less expensive than ST_Covers, but may return 1 in some cases where the geometry-expression does not actually cover geo2.

Therefore, this method can be useful as a primary filter when further processing will determine whether geometries interact in the desired way.

The implementation of ST_CoversFilter relies upon metadata associated with the stored geometries. Because the available metadata may change between server versions, depending upon how the data is loaded, or where ST_CoversFilter is used within a query, the expression geometry-expression.ST_CoversFilter(geo2) can return different results when geometry-expression does not cover geo2. Whenever geometry-expression covers geo2, ST_CoversFilter always returns 1.

• ST_Covers method for type ST_Geometry