distanceFromLocation不一致

我正在检查两个坐标之间的距离,以下两个坐标返回2.8英里。但是,如果我在google地图服务上进行检查,它会返回行驶距离4.1英里,最短距离是3.6英里。为什么会有这种差异?

- (IBAction)deliveryBtnClicked:(id)sender {
    CLLocation *loc1 = [[CLLocation alloc] initWithLatitude:-95.414640
 longitude:29.715660];

    CLLocation *loc2 = [[CLLocation alloc] initWithLatitude:-95.455080
 longitude:29.684080];

    CLLocationDistance distance = [loc1 distanceFromLocation:loc2];
    NSLog(@"%f", distance/1609.344);
}