title: Difficulties understanding MapKit Coordinate System
body: <p>I read the apple docs</p>
  
  <blockquote>
    <p>"A map point is an x and y value on the Mercator map projection" 
    A point is a graphical unit associated with the coordinate system of a UIView</p>
  </blockquote>
  
  <p>What is the difference logically between a Point and a MKPoint?
  I obviously need CGPoint to display something on the screen.
  So why does MapKit need MKMapPoint?</p>