adding ovelay on a map(objective c)

How to add ove开发者_JAVA技巧rlay on a map in objective c? (has any body tried it in iphone os 4.0)?

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here is a good article on using the MKPolyline overlay to add a route type annotation to your map. It should give you an idea how to add any of the other overlays. just implement the

- (MKOverlayView *)mapView:(MKMapView *)mapView viewForOverlay:(id )overlay

on your map delegate and give it the type of overlay your are drawing.