MKAnnotation is the protocol that annotation objects must implement in order to be rendered on apple maps. The only absolute requirement is to provide a coordinate attribute. This is a CLLocationCoordinate2D object containing the latitude and longitude of your annotation.
The application obtains the data from a resource. This could be Core Data, a ReST call or any other suitable source. It is recommended that this be done on a background thread to not impact UI performance.
This data is then used to instantiate MKAnnotation objects. In addition to the required CLLocationCoordinate2D attribute a title can be supplied to display underneath the map pin. A subtitle will be displayed when the user selects the pin.
Annotations can be added individually or as an array to a MKMapView. The map will call its viewFor delegate when it is time to render the annotation. The application should attempt to dequeue an annotation view and if one is not available it should create a new one. This is the same paradigm used for table rows.
Finally assign the annotation to the AnnotationView. Additional options exist in MKMarkerAnnotationView to further customize e.g. changing the color of the marker pin.
