判断一个经纬度在另外一个经纬度的方向

public static void main(String[] args) {

Test test = new Test();

String str=getDirection(“填入维度”,“填入经度”,“填入维度”,“填入经度”);

System.out.println(str);

}

public static double getAngle(double lat1, double lng1, double lat2,double lng2) {

double x1 = lng1;

double y1 = lat1;

double x2 = lng2;

double y2 = lat2;

double pi = Math.PI;

double w1 = y1 / 180 * pi;

double j1 = x1 / 180 * pi;

double w2 = y2 / 180 * pi;

double j2 = x2 / 180 * pi;

double ret;

if (j1 == j2) {

if (w1 > w2)

return 270; // 北半球的情况，南半球忽略

else if (w1 < w2)

return 90;

else

return -1;// 位置完全相同

}

ret = 4* Math.pow(Math.sin((w1 - w2) / 2), 2)- Math.pow(

Math.sin((j1 - j2) / 2) * (Math.cos(w1) - Math.cos(w2)),2);

ret = Math.sqrt(ret);

double temp = (Math.sin(Math.abs(j1 - j2) / 2) * (Math.cos(w1) + Math

.cos(w2)));

ret = ret / temp;

ret = Math.atan(ret) / pi * 180;

if (j1 > j2){ // 1为参考点坐标

if (w1 > w2)

ret += 180;

else

ret = 180 - ret;

} else if (w1 > w2)

ret = 360 - ret;

return ret;

}

/**

* @param lat1 纬度1

* @param lng1 经度1

* @param lat2 纬度2

* @param lng2 经度2

* @return 方向

*/

public static String getDirection(double lat1, double lng1, double lat2,double lng2) {

double jiaodu = getAngle(lat1, lng1, lat2, lng2);

if ((jiaodu <= 10) || (jiaodu > 350))

return "东";

if ((jiaodu > 10) && (jiaodu <= 80))

return "东北";

if ((jiaodu > 80) && (jiaodu <= 100))

return "北";

if ((jiaodu > 100) && (jiaodu <= 170))

return "西北";

if ((jiaodu > 170) && (jiaodu <= 190))

return "西";

if ((jiaodu > 190) && (jiaodu <= 260))

return "西南";

if ((jiaodu > 260) && (jiaodu <= 280))

return "南";

if ((jiaodu > 280) && (jiaodu <= 350))

return "东南";

return "";

}