iOS 两个坐标间距离的计算方法

    double R = 6371004; ////地球半径
    double dd = M_PI/180;
    
    double x1 = latitude1 * dd;
    double x2 = latitude2 * dd;
    
    double y1 = longitude1 * dd;
    double y2 = longitude2 * dd;
    
    double distance = (2*R*asin(sqrt(2-2*cos(x1)*cos(x2)*cos(y1-y2) - 2*sin(x1)*sin(x2))/2));
    
//    return  distance*1000;  //返回 km
//    return   distance;  //返回 m
   

另一种

    double EARTH_RADIUS = 6371004; ////地球半径
    double dd = M_PI/180;

    double redLat1 = latitude1 * dd;
    double redLat2 = latitude2 * dd;
    
    double a = latitude1 * dd - latitude2 * dd;
    double b = longitude1 * dd - longitude2 * dd;

    double s = 2 * asin(sqrt(pow(sin(a/2), 2) + cos(redLat1)*cos(redLat2)*pow(sin(b/2), 2)));
    s = s * EARTH_RADIUS; //返回单位:m