geometry-expression.ST_CoveredByFilter(geo2)

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

This test is cheaper than ST_CoveredBy, but may return 1 in some cases where the geometry-expression is not actually covered by 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_CoveredByFilter relies upon meta-data associated with the stored geometries. Because the available meta-data may change between server versions, depending upon how the data is loaded, or where ST_CoveredByFilter is used within a query, the expression geometry-expression.ST_CoveredByFilter(geo2) can return different results when geometry-expression is not covered by geo2. Whenever geometry-expression is covered by geo2, ST_CoveredByFilter will always return 1.

• ST_CoveredBy method for type ST_Geometry