com.revolsys.jts.algorithm

Class ConvexHull

java.lang.Object

com.revolsys.jts.algorithm.ConvexHull

public class ConvexHull
extends Object

Computes the convex hull of a Geometry. The convex hull is the smallest convex Geometry that contains all the points in the input Geometry.

Uses the Graham Scan algorithm.

Version:

1.7

Constructor Summary

Constructors

Constructor and Description
ConvexHull(Geometry geometry) Create a new convex hull construction for the input Geometry.
ConvexHull(Point[] pts, GeometryFactory geomFactory) Create a new convex hull construction for the input Coordinates array.

Method Summary

Methods

Modifier and Type	Method and Description
Geometry	getConvexHull() Returns a Geometry that represents the convex hull of the input geometry.
static boolean	isPointInRing(Point p, Point... ring) Tests whether a point lies inside or on a ring.
protected Point[]	toCoordinateArray(Stack<Point> stack) An alternative to Stack.toArray, which is not present in earlier versions of Java.

Methods inherited from class java.lang.Object

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

Constructor Detail

ConvexHull

public ConvexHull(Geometry geometry)

Create a new convex hull construction for the input Geometry.

ConvexHull

public ConvexHull(Point[] pts,
          GeometryFactory geomFactory)

Create a new convex hull construction for the input Coordinates array.

Method Detail

isPointInRing

public static boolean isPointInRing(Point p,
                    Point... ring)

Tests whether a point lies inside or on a ring. The ring may be oriented in either direction. A point lying exactly on the ring boundary is considered to be inside the ring.

This method does not first check the point against the envelope of the ring.

Parameters:

p - point to check for ring inclusion

ring - an array of coordinates representing the ring (which must have first point identical to last point)

Returns:

true if p is inside ring

See Also:

locatePointInRing

getConvexHull

public Geometry getConvexHull()

Returns a Geometry that represents the convex hull of the input geometry. The returned geometry contains the minimal number of points needed to represent the convex hull. In particular, no more than two consecutive points will be collinear.

Returns:

if the convex hull contains 3 or more points, a Polygon; 2 points, a LineString; 1 point, a Point; 0 points, an empty GeometryCollection.

toCoordinateArray

protected Point[] toCoordinateArray(Stack<Point> stack)

An alternative to Stack.toArray, which is not present in earlier versions of Java.