ST_Geometry::ST_LinearUnHash(index-hash[, srid])

The ST_LinearUnHash method generates a representative geometry for a linear hash string generated by ST_LinearHash(). The server maps geometries to a linear order for spatial indexes, and the ST_LinearHash method gives a binary string that defines this linear ordering. The ST_LinearUnHash reverses this operation to give a geometry that represents a particular hash string. The hash operation is lossy in the sense that multiple distinct geometries may hash to the same binary string. The ST_LinearUnHash method returns a geometry that covers any geometry that maps to the given linear hash.

The graphical plan for a query that uses a spatial index shows the linear hash values used to probe the spatial index. The ST_LinearUnHash method can be used to generate a geometry that represents these hashes.

• ST_LinearHash method for type ST_Geometry