1   /**
2    * Copyright (c) 2000-2009 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   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
12   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
13   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
14   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
15   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
16   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
17   * SOFTWARE.
18   */
19  
20  package com.liferay.util;
21  
22  /**
23   * <a href="Distance.java.html"><b><i>View Source</i></b></a>
24   *
25   * @author Brian Wing Shun Chan
26   *
27   */
28  public class Distance {
29  
30      public static double calculate(double lat1, double lon1,
31                                     double lat2, double lon2) {
32  
33          // Convert from radians to degrees
34  
35          lat1 = (Math.PI * lat1) / 180;
36          lon1 = (Math.PI * lon1) / 180;
37          lat2 = (Math.PI * lat2) / 180;
38          lon2 = (Math.PI * lon2) / 180;
39  
40          double miles =
41              3963.4 *
42              Math.acos(
43                  (Math.sin(lat1) * Math.sin(lat2)) +
44                  (Math.cos(lat1) * Math.cos(lat2) * Math.cos(lon1 - lon2)));
45  
46          return miles;
47      }
48  
49      public static double kmToMiles(double km) {
50          return km * 0.621;
51      }
52  
53      public static double milesToKm(double miles) {
54          return miles / 0.621;
55      }
56  
57  }