Here you can find the source of calculateDistance(double lat1, double lng1, double lat2, double lng2)
public static double calculateDistance(double lat1, double lng1, double lat2, double lng2)
//package com.java2s; //License from project: Open Source License public class Main { public static double calculateDistance(double lat1, double lng1, double lat2, double lng2) { double earthRadius = 6371393.0; double dLat = Math.toRadians(lat2 - lat1); double dLng = Math.toRadians(lng2 - lng1); double sindLat = Math.sin(dLat / 2); double sindLng = Math.sin(dLng / 2); double a = Math.pow(sindLat, 2) + Math.pow(sindLng, 2) * Math.cos(Math.toRadians(lat1)) * Math.cos(Math.toRadians(lat2)); double c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a)); double dist = earthRadius * c; return dist; }/*from ww w . j a va 2 s .c o m*/ }