oracle.spatial.geometry

Class Ops

java.lang.Object

oracle.spatial.geometry.Ops

public class Ops
extends java.lang.Object

Utility class for a variety of geometry operations.

Constructor Summary

Constructors

Constructor and Description
Ops()

Method Summary

Modifier and Type	Method and Description
static JGeometry	concaveHullDig(JGeometry geom, double digN) Return the concave hull of the specified multipoint geometry.
static JGeometry	convexHull(JGeometry geom) Return the convex hull of the input geometry.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Ops

public Ops()

Method Detail

convexHull

public static JGeometry convexHull(JGeometry geom)
                            throws java.lang.Exception

Return the convex hull of the input geometry. Currently circular arcs and circles will be replaced with their MBR (this behaviour is consistent with the database).

Processing is done as if the points were in the plane and may not be appropriate for geodetic geometries.

Parameters:

geom -

Returns:

Throws:

java.lang.Exception - "13050: unable to construct empty spatial object" if input has no points (May in future return an empty geometry)

concaveHullDig

public static JGeometry concaveHullDig(JGeometry geom,
                                       double digN)
                                throws java.lang.Exception

Return the concave hull of the specified multipoint geometry.

Uses the "dig" algorithm of Jin-Seo Park and Se-Jonh Oh, "A New Concave Hull Algorithm and Concaveness Measure for n-dimensional Datasets". Starting with a convex hull, interior points that are within (edge length)/digN of an edge will be added to the hull, "digging out" dents in the hull. Larger values of digN limit dents to be shallower.

Input geometry must be points only. Processing is done as if the points were on the plane and may not be appropriate for geodetic pointsets.

Parameters:

geom - a multipoint geometry

digN - non-negative parameter to the dig algorithm; larger values result in less "digging" of concavities. A digN of 0 will dig until all points are on the hull. Good values are data dependent; try a value of 3.0 to start.

Returns:

resulting polygon

Throws:

java.lang.Exception - if the input points do not have a valid convex hull "13024: polygon has less than three segments" (convex hull is not a polygon) "13028: Invalid Gtype in the SDO_GEOMETRY object" (input is not a MULTIPOINT)