iOS Components and Frameworks: Understanding the Advanced Features of the iOS SDK

Working with Map Overlays

Map overlays are similar to map annotations, in that any object can implement the MKOverlay protocol, and the map view delegate is asked to provide the associated view for a map overlay. Map overlays are different from annotations in that they can represent more than just a point. They can represent lines and shapes, so they are very useful for representing routes or areas of interest on a map. To demonstrate map overlays, the sample app provides a feature to add a geofence (described in more detail later in the section “Geofencing”) with a user-defined radius for a favorite place. When a geofence is added for a favorite place, the user’s selected radius will be displayed on the map with a circle around the place’s coordinate, ...