Class PointLocation

1	/*
2	* Copyright (c) 2016 Vivid Solutions.
3	*
4	* All rights reserved. This program and the accompanying materials
5	* are made available under the terms of the Eclipse Public License 2.0
6	* and Eclipse Distribution License v. 1.0 which accompanies this distribution.
7	* The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v20.html
8	* and the Eclipse Distribution License is available at
9	*
10	* http://www.eclipse.org/org/documents/edl-v10.php.
11	*/
12	package org.locationtech.jts.algorithm;
13
14	import org.locationtech.jts.geom.Coordinate;
15	import org.locationtech.jts.geom.CoordinateSequence;
16	import org.locationtech.jts.geom.Location;
17
18	/**
19	* Functions for locating points within basic geometric
20	* structures such as lines and rings.
21	*
22	* @author Martin Davis
23	*
24	*/
25	public class PointLocation {
26
27	/**
28	* Tests whether a point lies on the line defined by a list of
29	* coordinates.
30	*
31	* @param p the point to test
32	* @param line the line coordinates
33	* @return true if the point is a vertex of the line or lies in the interior
34	* of a line segment in the line
35	*/
36	public static boolean isOnLine(Coordinate p, Coordinate[] line)
37	{
38	LineIntersector lineIntersector = new RobustLineIntersector();
39	for (int i = 1; i < line.length; i++) {
40	Coordinate p0 = line[i - 1];
41	Coordinate p1 = line[i];
42	lineIntersector.computeIntersection(p, p0, p1);
43	if (lineIntersector.hasIntersection()) {
44	return true;
45	}
46	}
47	return false;
48	}
49
50	/**
51	* Tests whether a point lies on the line defined by a
52	* {@link CoordinateSequence}.
53	*
54	* @param p the point to test
55	* @param line the line coordinates
56	* @return true if the point is a vertex of the line or lies in the interior
57	* of a line segment in the line
58	*/
59	public static boolean isOnLine(Coordinate p, CoordinateSequence line)
60	{
61	LineIntersector lineIntersector = new RobustLineIntersector();
62	Coordinate p0 = new Coordinate();
63	Coordinate p1 = new Coordinate();
64	int n = line.size();
65	for (int i = 1; i < n; i++) {
66	line.getCoordinate(i-1, p0);
67	line.getCoordinate(i, p1);
68	lineIntersector.computeIntersection(p, p0, p1);
69	if (lineIntersector.hasIntersection()) {
70	return true;
71	}
72	}
73	return false;
74	}
75
76	/**
77	* Tests whether a point lies inside or on a ring. The ring may be oriented in
78	* either direction. A point lying exactly on the ring boundary is considered
79	* to be inside the ring.
80	* <p>
81	* This method does <i>not</i> first check the point against the envelope of
82	* the ring.
83	*
84	* @param p
85	* point to check for ring inclusion
86	* @param ring
87	* an array of coordinates representing the ring (which must have
88	* first point identical to last point)
89	* @return true if p is inside ring
90	*
91	* @see locatePointInRing
92	*/
93	public static boolean isInRing(Coordinate p, Coordinate[] ring)
94	{
95	return PointLocation.locateInRing(p, ring) != Location.EXTERIOR;
96	}
97
98	/**
99	* Determines whether a point lies in the interior, on the boundary, or in the
100	* exterior of a ring. The ring may be oriented in either direction.
101	* <p>
102	* This method does <i>not</i> first check the point against the envelope of
103	* the ring.
104	*
105	* @param p
106	* point to check for ring inclusion
107	* @param ring
108	* an array of coordinates representing the ring (which must have
109	* first point identical to last point)
110	* @return the {@link Location} of p relative to the ring
111	*/
112	public static int locateInRing(Coordinate p, Coordinate[] ring)
113	{
114	return RayCrossingCounter.locatePointInRing(p, ring);
115	}
116
117	}
118