For MyISAM and
        InnoDB tables, search operations in columns
        containing spatial data can be optimized using
        SPATIAL indexes. The most typical operations
        are:
- Point queries that search for all objects that contain a given point 
- Region queries that search for all objects that overlap a given region 
        MySQL uses R-Trees with quadratic
        splitting for SPATIAL indexes on
        spatial columns. A SPATIAL index is built
        using the minimum bounding rectangle (MBR) of a geometry. For
        most geometries, the MBR is a minimum rectangle that surrounds
        the geometries. For a horizontal or a vertical linestring, the
        MBR is a rectangle degenerated into the linestring. For a point,
        the MBR is a rectangle degenerated into the point.
      
        It is also possible to create normal indexes on spatial columns.
        In a non-SPATIAL index, you must declare a
        prefix for any spatial column except for
        POINT columns.
      
        MyISAM and InnoDB support
        both SPATIAL and
        non-SPATIAL indexes. Other storage engines
        support non-SPATIAL indexes, as described in
        Section 15.1.15, “CREATE INDEX Statement”.