Mercurial > dive4elements > gnv-client
comparison gnv-artifacts/src/main/java/de/intevation/gnv/utils/DistanceCalculator.java @ 1119:7c4f81f74c47
merged gnv-artifacts
| author | Thomas Arendsen Hein <thomas@intevation.de> |
|---|---|
| date | Fri, 28 Sep 2012 12:14:00 +0200 |
| parents | f953c9a559d8 |
| children |
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| 1027:fca4b5eb8d2f | 1119:7c4f81f74c47 |
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| 1 /* | |
| 2 * Copyright (c) 2010 by Intevation GmbH | |
| 3 * | |
| 4 * This program is free software under the LGPL (>=v2.1) | |
| 5 * Read the file LGPL.txt coming with the software for details | |
| 6 * or visit http://www.gnu.org/licenses/ if it does not exist. | |
| 7 */ | |
| 8 | |
| 9 package de.intevation.gnv.utils; | |
| 10 | |
| 11 import com.vividsolutions.jts.geom.Coordinate; | |
| 12 import com.vividsolutions.jts.geom.Point; | |
| 13 | |
| 14 import java.util.List; | |
| 15 | |
| 16 /** | |
| 17 * A helper class to calculate distances between points and coordinates. | |
| 18 * | |
| 19 * @author <a href="mailto:tim.englich@intevation.de">Tim Englich</a> | |
| 20 * | |
| 21 */ | |
| 22 public class DistanceCalculator { | |
| 23 | |
| 24 private final static double flattening = 1.0 / 298.257233563; | |
| 25 | |
| 26 private final static double earthRadius = 6378137.0 / 1000.0 ; | |
| 27 | |
| 28 /** | |
| 29 * Constructor | |
| 30 */ | |
| 31 public DistanceCalculator() { | |
| 32 } | |
| 33 | |
| 34 | |
| 35 /** | |
| 36 * Calculates the distance between two points. | |
| 37 * | |
| 38 * @param p1 First point. | |
| 39 * @param p2 Second point. | |
| 40 * @return the distance. | |
| 41 */ | |
| 42 public static double calculateDistance(Point p1, Point p2){ | |
| 43 return calculateDistance(p1.getCoordinate(), p2.getCoordinate()); | |
| 44 } | |
| 45 | |
| 46 | |
| 47 /** | |
| 48 * Calculates the distance between two coordinates. | |
| 49 * | |
| 50 * @param p1 First coordinate. | |
| 51 * @param p2 Second coordinate. | |
| 52 * @return the distance. | |
| 53 */ | |
| 54 public static double calculateDistance(Coordinate p1, Coordinate p2){ | |
| 55 double resultValue = 0.0; | |
| 56 | |
| 57 double b1 = p1.y; | |
| 58 double b2 = p2.y; | |
| 59 | |
| 60 double l1 = p1.x; | |
| 61 double l2 = p2.x; | |
| 62 | |
| 63 | |
| 64 double F = (b1 + b2) / 2.0; | |
| 65 double G = (b1 - b2) / 2.0; | |
| 66 double l = (l1 - l2) / 2.0; | |
| 67 | |
| 68 F = (Math.PI / 180.0) * F; | |
| 69 G = (Math.PI / 180.0) * G; | |
| 70 l = (Math.PI / 180.0) * l; | |
| 71 | |
| 72 double S = ((Math.sin(G) * Math.sin(G)) * ((Math.cos(l) * Math.cos(l))))+ | |
| 73 ((Math.cos(F) * Math.cos(F)) * ((Math.sin(l) * Math.sin(l)))); | |
| 74 | |
| 75 double C = ((Math.cos(G) * Math.cos(G)) * ((Math.cos(l) * Math.cos(l))))+ | |
| 76 ((Math.sin(F) * Math.sin(F)) * ((Math.sin(l) * Math.sin(l)))); | |
| 77 | |
| 78 double w = Math.atan(Math.sqrt((S/C))); | |
| 79 | |
| 80 double D = 2.0 * w * earthRadius; | |
| 81 | |
| 82 double R = Math.sqrt((S*C)) / w; | |
| 83 | |
| 84 double H1 = (3.0 * R - 1.0 ) / (2.0 * C); | |
| 85 double H2 = (3.0 * R + 1.0 ) / (2.0 * S); | |
| 86 | |
| 87 resultValue = D * (1 + (flattening * H1 * (Math.sin(F) * Math.sin(F)) * | |
| 88 (Math.cos(G) * Math.cos(G))) - | |
| 89 (flattening * H2 * (Math.cos(F) * Math.cos(F)) * | |
| 90 (Math.sin(G) * Math.sin(G)))); | |
| 91 | |
| 92 return resultValue; | |
| 93 } | |
| 94 | |
| 95 /** | |
| 96 * Calculates the length of a path specified by coordinates in <i>path</i>. | |
| 97 * | |
| 98 * @param path A list of coordinates. | |
| 99 * @return the length of the given path. | |
| 100 */ | |
| 101 public static final double calculateDistance(List<Coordinate> path) { | |
| 102 int N = path.size(); | |
| 103 if (N < 2) { | |
| 104 return 0d; | |
| 105 } | |
| 106 double sum = 0d; | |
| 107 for (int i = 1; i < N; ++i) { | |
| 108 sum += calculateDistance(path.get(i-1), path.get(i)); | |
| 109 } | |
| 110 return sum; | |
| 111 } | |
| 112 | |
| 113 } | |
| 114 // vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 : |