title: How to get directions to a MKPointAnnotation
body: <p>I have created a map that has an <code>MKPointAnnotation</code> which is the single point on the map (besides the users location). I am trying to work out how to amend some existing code I have to get the Driving directions to this point.  </p>
  
  <p>This is the code that I use early in the application. At this earlier point in the application I have the following which gives me a CLPlaceMark.  </p>
  
  <pre><code>[geocoder geocodeAddressString:location
               completionHandler:^(NSArray* placemarks, NSError* error){
                   if (placemarks &amp;&amp; placemarks.count &gt; 0) {
                       CLPlacemark *topResult = [placemarks objectAtIndex:0];
  </code></pre>
  
  <p>Collecting directions:</p>
  
  <pre><code>MKDirectionsRequest *request = [[MKDirectionsRequest alloc] init];
                           [request setSource:[MKMapItem mapItemForCurrentLocation]];
                           MKPlacemark *mkDest = [[MKPlacemark alloc] initWithPlacemark:topResult];
                           [request setDestination:[[MKMapItem alloc] initWithPlacemark:mkDest]];
                           [request setTransportType:MKDirectionsTransportTypeWalking]; // This can be limited to automobile and walking directions.
                           [request setRequestsAlternateRoutes:NO]; 
                           MKDirections *directions = [[MKDirections alloc] initWithRequest:request];
                           [directions calculateDirectionsWithCompletionHandler:^(MKDirectionsResponse *response, NSError *error) {
                               if (!error) {
                                   for (MKRoute *route in [response routes]) {
                                       [self.mapView addOverlay:[route polyline] level:MKOverlayLevelAboveRoads]; // Draws the route above roads, but below labels.
                                       // You can also get turn-by-turn steps, distance, advisory notices, ETA, etc by accessing various route properties.
                                   }
                               }
                           }];
  </code></pre>
  
  <p><strong>Issue</strong><br>
  The issue is that later on I seem to only be able to access the <code>self.mapView.annotations</code>. So I have access to the <code>MKPointAnnotation</code>, but I need access to a <code>CLPlacemark</code> for the <code>setDestination</code> on the <code>MKDirectionsRequest</code>. </p>
  
  <p>So the question is how do I get a <code>CLPacemark</code> from a <code>MKPointAnnotation</code>, or is there a different approach to getting directions to a single point without that requirement? Thanks</p>