/*
* GeoSolutions GeoSolutions Android Map Library - Digital mapping on Android based devices
* Copyright (C) 2013 GeoSolutions (www.geo-solutions.it)
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package it.geosolutions.android.map.utils;
/**
* An utility class to calculate geodesic distance between two point on earth surface.
* source: http://www.spadamar.com/2007/12/calcolo-della-distanza-geodetica-tra-due-punti-della-superficie-terrestre/
* @author Jacopo Pianigiani (jacopo.pianigiani85@gmail.com)
*/
public class GeodesicDistance {
/**
* Method to calculate distance in kilometers between two points on earth surface,whose coordinates are
* passed through arguments.
* @param lon_startX longitude of first point.
* @param lat_startY latitude of first point.
* @param lon_endX longitude of second point.
* @param lat_endY latitude of second point.
* @return
*/
public static double getDistance(double lon_startX, double lat_startY, double lon_endX, double lat_endY){
double R = 6371; //Radius of earth(expressed in kilometers).
double lat_alfa, lat_beta, lon_alfa, lon_beta;
//Convert latitude and longitude from degrees to radians
lat_alfa = (Math.PI * lat_startY) / 180;
lat_beta = (Math.PI * lat_endY) / 180;
lon_alfa = (Math.PI * lon_startX) / 180;
lon_beta = (Math.PI * lon_endX) / 180;
double fi = Math.abs(lon_alfa - lon_beta);
double p = Math.acos(Math.sin(lat_beta) * Math.sin(lat_alfa) +
Math.cos(lat_beta) * Math.cos(lat_alfa) * Math.cos(fi));
return p * R;
}
}