Functions That Test Spatial Relations Between Geometry Objects ST_Intersects()  handles its arguments as described in the introduction to this section. • ST_Overlaps( g1 ,  g2 ) Two geometries  spatially overlap  if they intersect and their intersection results in a geometry of the same dimension but not equal to either of the given geometries. This function returns 1 or 0 to indicate whether  g1  spatially overlaps  g2 . ST_Overlaps()  handles its arguments as described in the introduction to this section except that the return value is  NULL  for the additional condition that the dimensions of the two geometries are not equal. • ST_Touches( g1 ,  g2 ) Two geometries  spatially touch  if their interiors do not intersect, but the boundary of one of the geometries intersects either the boundary or the interior of the other. ST_Touches()  handles its arguments as described in the introduction to this section except that the return value is  NULL  for the additional condition that both geometries are of dimension 0 ( Point  or MultiPoint ). This function returns 1 or 0 to indicate whether  g1  spatially touches  g2 . • ST_Within( g1 ,  g2 ) Returns 1 or 0 to indicate whether  g1  is spatially within  g2 . This tests the opposite relationship as ST_Contains() . ST_Within()  handles its arguments as described in the introduction to this section. 12.17.9.2 Spatial Relation Functions That Use Minimum Bounding Rectangles MySQL provides several MySQL-specific functions that test the relationship between minimum bounding rectangles (MBRs) of two geometries  g1  and  g2 . The return values 1 and 0 indicate true and false, respectively. The bounding box of a point is interpreted as a point that is both boundary and interior. The bounding box of a straight horizontal or vertical line is interpreted as a line where the interior of the line is also boundary. The endpoints are boundary points. If any of the parameters are geometry collections, the interior, boundary, and exterior of those parameters are those of the union of all elements in the collection. Functions in this section detect arguments in either Cartesian or geographic spatial reference systems (SRSs), and return results appropriate to the SRS. Unless otherwise specified, functions in this section handle their geometry arguments as follows: •If any argument is  NULL  or an empty geometry, the return value is  NULL . •If any geometry argument is a syntactically well-formed geometry in an undefined spatial reference system (SRS), an  ER_SRS_NOT_FOUND  error occurs. •If any geometry argument is not a syntactically well-formed geometry, an  ER_GIS_INVALID_DATA  error occurs. 2330