//地球半徑,單位米 private const double EARTH_RADIUS = 6378137; /// <summary> /// 計算兩點位置的距離,返回兩點的距離,單位 米 /// 該公式為GOOGLE提供,誤差小於0.2米 /// </summary> /// <param name="lat1">第一點緯度</param> /// <param name="lng1">第一點經度</param> /// <param name="lat2">第二點緯度</param> /// <param name="lng2">第二點經度</param> /// <returns></returns> public static double GetDistance(double lat1, double lng1, double lat2, double lng2) { double radLat1 = Rad(lat1); double radLng1 = Rad(lng1); double radLat2 = Rad(lat2); double radLng2 = Rad(lng2); double a = radLat1 - radLat2; double b = radLng1 - radLng2; double result = 2 * Math.Asin(Math.Sqrt(Math.Pow(Math.Sin(a / 2), 2) + Math.Cos(radLat1) * Math.Cos(radLat2) * Math.Pow(Math.Sin(b / 2), 2))) * EARTH_RADIUS; return result; } /// <summary> /// 經緯度轉化成弧度 /// </summary> /// <param name="d"></param> /// <returns></returns> private static double Rad(double d) { return (double)d * Math.PI / 180d; }