Android計算地圖上兩點距離

最近項目要用到定位地圖上兩個座標的位置，網上找了一下發現：

在android中可採用如下代碼獲取距離: 

public double getDistance(double lat1, double lon1, double lat2, double lon2) {
        float[] results=new float[1];
        Location.distanceBetween(lat1, lon1, lat2, lon2, results);
        return results[0];
    }

在其他設備若沒有類似android的Location的distanceBetween方法開採用如下代碼獲取:

double distance(double lat1, double lon1, double lat2, double lon2) {
        double theta = lon1 - lon2;
        double dist = Math.sin(deg2rad(lat1)) * Math.sin(deg2rad(lat2))
                    + Math.cos(deg2rad(lat1)) * Math.cos(deg2rad(lat2))
                    * Math.cos(deg2rad(theta));
        dist = Math.acos(dist);
        dist = rad2deg(dist);
        double miles = dist * 60 * 1.1515;
        return miles;
    }
    //將角度轉換爲弧度
    static double deg2rad(double degree) {
        return degree / 180 * Math.PI;
    }
    //將弧度轉換爲角度
    static double rad2deg(double radian) {
        return radian * 180 / Math.PI;
    }

今天還發現了這樣一種計算距離的方法：

public static double getDistatce(double paramDouble1, double paramDouble2, double paramDouble3, double paramDouble4)
  {
    double d1 = 3.141592653589793D * (paramDouble2 - paramDouble1) / 180.0D;
    double d2 = 3.141592653589793D * (paramDouble4 - paramDouble3) / 180.0D;
    double d3 = Math.sin(d1 / 2.0D) * Math.sin(d1 / 2.0D) + Math.cos(3.141592653589793D * paramDouble1 / 180.0D) * Math.cos(3.141592653589793D * paramDouble2 / 180.0D) * Math.sin(d2 / 2.0D) * Math.sin(d2 / 2.0D);
    return 6371.0D * (2.0D * Math.atan2(Math.sqrt(d3), Math.sqrt(1.0D - d3)));
  }

這個計算得出的結果是英里,如果要轉換成公里,需要乘以1.609344,若是海里需要乘以0.8684

自己試一下喔！