public class ST_Area
extends GenericUDF
Returns the area of a polygon or multipolygon geometry.
Format:
 ST_Area(geometry ST_Geometry, tolerance NUMBER) - returns the area of a polygon or multi polygon geometry
  The tolerance is optional.
  By default the tolerance is 0.05 for geodetic geometries and 0 for non geodetic.
  For projected data, the area is in the same unit as the unit of projection. For Geodetic, the area is in square meters.
  Return -1 in case of error.
Example:
 select ST_Area(
  ST_Polygon('{"type": "Polygon","coordinates": [[[1, 2], [5, 2], [5, 7], [1, 7], [1, 2]]]}', 0)
 ) from hivetable LIMIT 1; -- return 20