1   /**
2    * Copyright (c) 2000-2010 Liferay, Inc. All rights reserved.
3    *
4    * The contents of this file are subject to the terms of the Liferay Enterprise
5    * Subscription License ("License"). You may not use this file except in
6    * compliance with the License. You can obtain a copy of the License by
7    * contacting Liferay, Inc. See the License for the specific language governing
8    * permissions and limitations under the License, including but not limited to
9    * distribution rights of the Software.
10   *
11   *
12   *
13   */
14  
15  package com.liferay.util;
16  
17  /**
18   * <a href="Distance.java.html"><b><i>View Source</i></b></a>
19   *
20   * @author Brian Wing Shun Chan
21   */
22  public class Distance {
23  
24      public static double calculate(double lat1, double lon1,
25                                     double lat2, double lon2) {
26  
27          // Convert from radians to degrees
28  
29          lat1 = (Math.PI * lat1) / 180;
30          lon1 = (Math.PI * lon1) / 180;
31          lat2 = (Math.PI * lat2) / 180;
32          lon2 = (Math.PI * lon2) / 180;
33  
34          double miles =
35              3963.4 *
36              Math.acos(
37                  (Math.sin(lat1) * Math.sin(lat2)) +
38                  (Math.cos(lat1) * Math.cos(lat2) * Math.cos(lon1 - lon2)));
39  
40          return miles;
41      }
42  
43      public static double kmToMiles(double km) {
44          return km * 0.621;
45      }
46  
47      public static double milesToKm(double miles) {
48          return miles / 0.621;
49      }
50  
51  }