Class Length

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
17	/**
18	* Functions for computing length.
19	*
20	* @author Martin Davis
21	*
22	*/
23	public class Length {
24
25	/**
26	* Computes the length of a linestring specified by a sequence of points.
27	*
28	* @param pts the points specifying the linestring
29	* @return the length of the linestring
30	*/
31	public static double ofLine(CoordinateSequence pts)
32	{
33	// optimized for processing CoordinateSequences
34	int n = pts.size();
35	if (n <= 1)
36	return 0.0;
37
38	double len = 0.0;
39
40	Coordinate p = new Coordinate();
41	pts.getCoordinate(0, p);
42	double x0 = p.x;
43	double y0 = p.y;
44
45	for (int i = 1; i < n; i++) {
46	pts.getCoordinate(i, p);
47	double x1 = p.x;
48	double y1 = p.y;
49	double dx = x1 - x0;
50	double dy = y1 - y0;
51
52	len += Math.sqrt(dx * dx + dy * dy);
53
54	x0 = x1;
55	y0 = y1;
56	}
57	return len;
58	}
59
60	}
61