Mercurial > dive4elements > gnv-client
comparison gnv-artifacts/src/main/java/de/intevation/gnv/utils/DistanceCalculator.java @ 875:5e9efdda6894
merged gnv-artifacts/1.0
| author | Thomas Arendsen Hein <thomas@intevation.de> |
|---|---|
| date | Fri, 28 Sep 2012 12:13:56 +0200 |
| parents | 05bf8534a35a |
| children | f953c9a559d8 |
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| 722:bb3ffe7d719e | 875:5e9efdda6894 |
|---|---|
| 1 package de.intevation.gnv.utils; | |
| 2 | |
| 3 import com.vividsolutions.jts.geom.Coordinate; | |
| 4 import com.vividsolutions.jts.geom.Point; | |
| 5 | |
| 6 import java.util.List; | |
| 7 | |
| 8 /** | |
| 9 * A helper class to calculate distances between points and coordinates. | |
| 10 * | |
| 11 * @author <a href="mailto:tim.englich@intevation.de">Tim Englich</a> | |
| 12 * | |
| 13 */ | |
| 14 public class DistanceCalculator { | |
| 15 | |
| 16 private final static double flattening = 1.0 / 298.257233563; | |
| 17 | |
| 18 private final static double earthRadius = 6378137.0 / 1000.0 ; | |
| 19 | |
| 20 /** | |
| 21 * Constructor | |
| 22 */ | |
| 23 public DistanceCalculator() { | |
| 24 } | |
| 25 | |
| 26 | |
| 27 /** | |
| 28 * Calculates the distance between two points. | |
| 29 * | |
| 30 * @param p1 First point. | |
| 31 * @param p2 Second point. | |
| 32 * @return the distance. | |
| 33 */ | |
| 34 public static double calculateDistance(Point p1, Point p2){ | |
| 35 return calculateDistance(p1.getCoordinate(), p2.getCoordinate()); | |
| 36 } | |
| 37 | |
| 38 | |
| 39 /** | |
| 40 * Calculates the distance between two coordinates. | |
| 41 * | |
| 42 * @param p1 First coordinate. | |
| 43 * @param p2 Second coordinate. | |
| 44 * @return the distance. | |
| 45 */ | |
| 46 public static double calculateDistance(Coordinate p1, Coordinate p2){ | |
| 47 double resultValue = 0.0; | |
| 48 | |
| 49 double b1 = p1.y; | |
| 50 double b2 = p2.y; | |
| 51 | |
| 52 double l1 = p1.x; | |
| 53 double l2 = p2.x; | |
| 54 | |
| 55 | |
| 56 double F = (b1 + b2) / 2.0; | |
| 57 double G = (b1 - b2) / 2.0; | |
| 58 double l = (l1 - l2) / 2.0; | |
| 59 | |
| 60 F = (Math.PI / 180.0) * F; | |
| 61 G = (Math.PI / 180.0) * G; | |
| 62 l = (Math.PI / 180.0) * l; | |
| 63 | |
| 64 double S = ((Math.sin(G) * Math.sin(G)) * ((Math.cos(l) * Math.cos(l))))+ | |
| 65 ((Math.cos(F) * Math.cos(F)) * ((Math.sin(l) * Math.sin(l)))); | |
| 66 | |
| 67 double C = ((Math.cos(G) * Math.cos(G)) * ((Math.cos(l) * Math.cos(l))))+ | |
| 68 ((Math.sin(F) * Math.sin(F)) * ((Math.sin(l) * Math.sin(l)))); | |
| 69 | |
| 70 double w = Math.atan(Math.sqrt((S/C))); | |
| 71 | |
| 72 double D = 2.0 * w * earthRadius; | |
| 73 | |
| 74 double R = Math.sqrt((S*C)) / w; | |
| 75 | |
| 76 double H1 = (3.0 * R - 1.0 ) / (2.0 * C); | |
| 77 double H2 = (3.0 * R + 1.0 ) / (2.0 * S); | |
| 78 | |
| 79 resultValue = D * (1 + (flattening * H1 * (Math.sin(F) * Math.sin(F)) * | |
| 80 (Math.cos(G) * Math.cos(G))) - | |
| 81 (flattening * H2 * (Math.cos(F) * Math.cos(F)) * | |
| 82 (Math.sin(G) * Math.sin(G)))); | |
| 83 | |
| 84 return resultValue; | |
| 85 } | |
| 86 | |
| 87 /** | |
| 88 * Calculates the length of a path specified by coordinates in <i>path</i>. | |
| 89 * | |
| 90 * @param path A list of coordinates. | |
| 91 * @return the length of the given path. | |
| 92 */ | |
| 93 public static final double calculateDistance(List<Coordinate> path) { | |
| 94 int N = path.size(); | |
| 95 if (N < 2) { | |
| 96 return 0d; | |
| 97 } | |
| 98 double sum = 0d; | |
| 99 for (int i = 1; i < N; ++i) { | |
| 100 sum += calculateDistance(path.get(i-1), path.get(i)); | |
| 101 } | |
| 102 return sum; | |
| 103 } | |
| 104 | |
| 105 } | |
| 106 // vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 : |