计算两个GPS坐标的方位与距离

计算距离，返回米

double getDistanceByGps(double lat1,double lng1,double lat2,double lng2){    double PI = 3.1415926;    double EarthRadius = 6378137;    double Rad = PI / 180.0;    double radlat1 = lat1 * Rad;    double radlat2 = lat2 * Rad;    double a = radlat1 - radlat2;    double b = (lng1 - lng2)*Rad;    double s = 2*asin(sqrt(pow(sin(a/2),2)+cos(radlat1)*cos(radlat2)*pow(sin(b/2),2)));    s = s*EarthRadius;    s = round(s * 10000) / 10000;    return s;}

计算方位，返回0到360°

double getAngleByGps(double lat1,double lng1,double lat2,double lng2){    double PI = 3.1415926;    double x = sin(lng2 - lng1) * cos(lat2);    double y = cos(lat1) * sin(lat2) - sin(lat1) * cos(lat2) * cos(lng2 - lng1);    double angle = atan2(x,y) * 180 / PI;    return angle>0?angle:angle+360;}