1   /**
2    * Copyright (c) 2000-2009 Liferay, Inc. All rights reserved.
3    *
4    * Permission is hereby granted, free of charge, to any person obtaining a copy
5    * of this software and associated documentation files (the "Software"), to deal
6    * in the Software without restriction, including without limitation the rights
7    * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
8    * copies of the Software, and to permit persons to whom the Software is
9    * furnished to do so, subject to the following conditions:
10   *
11   * The above copyright notice and this permission notice shall be included in
12   * all copies or substantial portions of the Software.
13   *
14   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
17   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
18   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
19   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
20   * SOFTWARE.
21   */
22  
23  package com.liferay.util;
24  
25  /**
26   * <a href="Distance.java.html"><b><i>View Source</i></b></a>
27   *
28   * @author Brian Wing Shun Chan
29   *
30   */
31  public class Distance {
32  
33      public static double calculate(double lat1, double lon1,
34                                     double lat2, double lon2) {
35  
36          // Convert from radians to degrees
37  
38          lat1 = (Math.PI * lat1) / 180;
39          lon1 = (Math.PI * lon1) / 180;
40          lat2 = (Math.PI * lat2) / 180;
41          lon2 = (Math.PI * lon2) / 180;
42  
43          double miles =
44              3963.4 *
45              Math.acos(
46                  (Math.sin(lat1) * Math.sin(lat2)) +
47                  (Math.cos(lat1) * Math.cos(lat2) * Math.cos(lon1 - lon2)));
48  
49          return miles;
50      }
51  
52      public static double kmToMiles(double km) {
53          return km * 0.621;
54      }
55  
56      public static double milesToKm(double miles) {
57          return miles / 0.621;
58      }
59  
60  }