Why is MKMapView putting me in the sea?

Question

I have this code to set the map at the user's location:

MKCoordinateSpan span;
span.latitudeDelta=0.2;
span.longitudeDelta=0.2; 

CLLocationCoordinate2D location=mapView.userLocation.coordinate;
location = mapView.userLocation.location.coordinate;

MKCoordinateRegion region;
region.span=span;
region.center=location;

[mapView setRegion:region animated:TRUE];
[mapView regionThatFits:region];

Now when I do mapView.showsUserLocation=YES it shows my location at the right place (on my device, and the apple hq in the simulator) however, both times the code above puts me in the sea somewhere near africa!

Any ideas?

Answer 1

The latitude/longitude pair 0/0 is on the equator due south of Greenwich, England. That spot is in the Gulf of Guinea, off the West coast of Africa. If that's where your pin is getting placed, then your mapView.userLocation isn't getting set.

Probably your code here is running before MKMapKit has had a chance to get its location. What you really want to do is have your viewController adopt the MKMapKitDelegate protocol, set the .delegate property of your map view to self, and then implement the method:

- (void)mapView:(MKMapView *)mapView didUpdateUserLocation:(MKUserLocation *)userLocation

That method will get called when the map kit locates the user, and you can use the userLocation value you get passed there to set the region on the map. Until that gets called the first time, though, the MapView is still working on locating itself, and your asking about its location is premature.

Also, your regionThatFits there at the end is a no-op. That method doesn't resize the region in place, it actually returns a resized region, for you to use however you will. So you want to set your map view's region to what that method returns. Like this:

[mapView setRegion:[mapView regionThatFits:region] animated:TRUE];