UImapview：使用lat和lon如何计算obj c中的速度

Question

在我的应用程序中获取经度，纬度并计算速度。

首先获取用户当前位置的经度，纬度。使用此代码得到了它。

[[self mapView] setShowsUserLocation:YES];
    locationManager = [[CLLocationManager alloc] init];
    [ locationManager setDelegate:self];
    // we have to setup the location manager with permission in later iOS versions
    if ([ locationManager respondsToSelector:@selector(requestWhenInUseAuthorization)]) {
        [ locationManager requestWhenInUseAuthorization];
    }
    [ locationManager setDesiredAccuracy:kCLLocationAccuracyBest];
     [locationManager startUpdatingLocation];


-(void) locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations
{
    CLLocation *location = locations.lastObject;


    [[self labelLatitude] setText:[NSString stringWithFormat:@"%.6f", location.coordinate.latitude]];
    [[self labelLongitude] setText:[NSString stringWithFormat:@"%.6f", location.coordinate.longitude]];
    [[self labelAltitude] setText:[NSString stringWithFormat:@"%.2f feet", location.altitude*METERS_FEET]];

    MKCoordinateRegion viewRegion = MKCoordinateRegionMakeWithDistance(location.coordinate, 2*METERS_MILE, 2*METERS_MILE);
    [[self mapView] setRegion:viewRegion animated:YES];

}

我的问题：如果用户移动新地点意味着经度，纬度会成功更改。如何保存用户当前位置并更新新位置。以及如何计算速度。帮助我，谢谢你。