iOS 地图 通过经纬度计算两点间距离

- (double)calculateStart:(CLLocationCoordinate2D)start end:(CLLocationCoordinate2D)end {
    
    double meter = 0;
    
    double startLongitude = start.longitude;
    double startLatitude = start.latitude;
    double endLongitude = end.longitude;
    double endLatitude = end.latitude;
    
    double radLatitude1 = startLatitude * M_PI / 180.0;
    double radLatitude2 = endLatitude * M_PI / 180.0;
    double a = fabs(radLatitude1 - radLatitude2);
    double b = fabs(startLongitude * M_PI / 180.0 - endLongitude * M_PI / 180.0);
    
    double s = 2 * asin(sqrt(pow(sin(a/2),2) + cos(radLatitude1) * cos(radLatitude2) * pow(sin(b/2),2)));
    s = s * EARTH_RADIUS;
    
    meter = round(s * 10000) / 10000; //返回距离单位是米
    return meter;
}