Exposing JTS’s MinimumBoundingCircle functionality

   /**
   * ST_MinimumBoundingCircle
   * Computes the Minimum Bounding Circle (MBC) for the points in a Geometry.
   * The MBC is the smallest circle which contains all the input points (this
   * is sometimes known as the Smallest Enclosing Circle). This is equivalent
   * to computing the Maximum Diameter of the input point set.
   * @param p_geom      : sdo_geometry : first geometry subject to MBC calculation
   * @param p_precision : int : number of decimal places of precision
   * @return  circle    : sdo_geometry : Result of MBC calculation
   * @author Martin Davis, JTS 1.12
   * @history Simon Greener, September 2011, Original Coding of wrapper
   * @copyright  : Licensed under a Creative Commons Attribution-Share Alike 2.5 Australia License.
   *               http://creativecommons.org/licenses/by-sa/2.5/au/
   **/
   FUNCTION ST_MinimumBoundingCircle(p_geom      IN mdsys.sdo_geometry,
                                     p_precision IN NUMBER)
     RETURN mdsys.sdo_geometry deterministic;
 .
   /**
   * ST_MinimumBoundingCircle
   * Computes the Minimum Bounding Circle (MBC) for the points in a Geometry.
   * The MBC is the smallest circle which contains all the input points (this
   * is sometimes known as the Smallest Enclosing Circle). This is equivalent
   * to computing the Maximum Diameter of the input point set.
   * @param p_geom      : sdo_geometry : first geometry subject to MBC calculation
   * @param p_precision : int : number of decimal places of precision
   * @param p_srid      : int : SRID of projected space in which actual overlay occurs before
   *                            being projected back to p_geom1.sdo_srid.
   * @return  circle    : sdo_geometry : Result of MBC calculation
   * @author Martin Davis, JTS 1.12
   * @history Simon Greener, September 2011, Original Coding of wrapper
   * @copyright  : Licensed under a Creative Commons Attribution-Share Alike 2.5 Australia License.
   *               http://creativecommons.org/licenses/by-sa/2.5/au/
   **/
   FUNCTION ST_MinimumBoundingCircle(p_geom      IN mdsys.sdo_geometry,
                                     p_precision IN NUMBER,
                                     p_srid      IN NUMBER )
     RETURN mdsys.sdo_geometry deterministic;

 -- Point is returned as is
 SELECT SC4O.ST_MinimumBoundingCircle(sdo_geometry(2001,NULL,sdo_point_type(1,1,NULL),NULL,NULL),2) AS mbc FROM dual;
 .
 MBC
 ----------------------------------------------------------------------
 MDSYS.SDO_GEOMETRY(2001,NULL,MDSYS.SDO_POINT_TYPE(1,1,NULL),NULL,NULL)
 .
 -- Straight line defined by two points
 SELECT SC4O.ST_MinimumBoundingCircle(sdo_geometry('MULTIPOINT ((10 10), (20 20))',0),2) AS mbc  FROM dual;
 .
 MBC
 ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 MDSYS.SDO_GEOMETRY(2003,NULL,MDSYS.SDO_POINT_TYPE(15,15,7.07106781186548),MDSYS.SDO_ELEM_INFO_ARRAY(1,1003,4),MDSYS.SDO_ORDINATE_ARRAY(7.92893218813452,15,22.07106781186548,15,15,22.07106781186548))
 .
 -- Three Points In Line
 SELECT SC4O.ST_MinimumBoundingCircle(sdo_geometry('MULTIPOINT ((10 10), (20 20), (30 30))',0),2) AS mbc  FROM dual;
 .
 MBC
 -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 MDSYS.SDO_GEOMETRY(2003,NULL,MDSYS.SDO_POINT_TYPE(20,20,14.142135623731),MDSYS.SDO_ELEM_INFO_ARRAY(1,1003,4),MDSYS.SDO_ORDINATE_ARRAY(5.857864376269,20,34.142135623731,20,20,34.142135623731))
 .
 -- three points
 SELECT SC4O.ST_MinimumBoundingCircle(sdo_geometry('MULTIPOINT ((10 10), (20 20), (10 20))',0),2) AS mbc  FROM dual;
 .
 MBC
 ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 MDSYS.SDO_GEOMETRY(2003,NULL,MDSYS.SDO_POINT_TYPE(15,15,7.07106781186548),MDSYS.SDO_ELEM_INFO_ARRAY(1,1003,4),MDSYS.SDO_ORDINATE_ARRAY(7.92893218813452,15,22.07106781186548,15,15,22.07106781186548))
 .
 -- Triangle With Middle Point
 SELECT SC4O.ST_MinimumBoundingCircle(sdo_geometry('MULTIPOINT ((10 10), (20 20), (10 20), (15 19))',0),2) AS mbc  FROM dual;
 .
 MBC
 ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 MDSYS.SDO_GEOMETRY(2003,NULL,MDSYS.SDO_POINT_TYPE(15,15,7.07106781186548),MDSYS.SDO_ELEM_INFO_ARRAY(1,1003,4),MDSYS.SDO_ORDINATE_ARRAY(7.92893218813452,15,22.07106781186548,15,15,22.07106781186548))
 

Now let’s test and visualise some lines and circles.

 with line as (
 select sdo_geometry('LINESTRING(0 0, 10 10, 10 0, 20 10)',0) as line from dual
 )
 select SC4O.ST_MinimumBoundingCircle(line,2) as dGeom from line;
 .
 DGEOM
 -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 MDSYS.SDO_GEOMETRY(2003,NULL,MDSYS.SDO_POINT_TYPE(10,5,11.1803398874989),MDSYS.SDO_ELEM_INFO_ARRAY(1,1003,4),MDSYS.SDO_ORDINATE_ARRAY(-1.1803398874989,5,21.1803398874989,5,10,16.1803398874989))
 .
 -- Optimized Rectangle
 with rect as (
 select sdo_geometry(2003,null,null,sdo_elem_info_array(1,1003,3),sdo_ordinate_array(1,1,10,10)) as rect from dual
 )
 select SC4O.ST_MinimumBoundingCircle(rect,2) as dGeom from rect;
 .
 DGEOM
 ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 MDSYS.SDO_GEOMETRY(2003,NULL,MDSYS.SDO_POINT_TYPE(5.5,5.5,6.36396103067893),MDSYS.SDO_ELEM_INFO_ARRAY(1,1003,4),MDSYS.SDO_ORDINATE_ARRAY(-0.86396103067893,5.5,11.86396103067893,5.5,5.5,11.86396103067893))