How to open call out MKAnnotationView programmatically? (iPhone, MapKit)

Question

I want to open up the callout for an MKPinAnnotationView programmatically. Eg I drop 10 pins on the map, and want to open up the one closest to me. How would I

Answer 1

In swift 3 this is updated to:

func openAnnotation(annotation: MkAnnotation) {
_ = [mapView .selectAnnotation(annotation, animated: true)]
}

and can be called using any annotation (this will open the annotation callout view and attempt to center the annotation on the map)

For example using the second annotation in a hypothetical list of annotations.

openAnnotation(annotation: mapView.annotations[1])