MapKit: How can I pan and zoom to fit all my annotations?

Question

So I've got a bunch of annotations spread out on my map... everything is just dandy. Now I need to be able to set the map's position and zoom so they all fit perfectly. How can I do this?

Answer 1

From Apple forums...

- (void)recenterMap {

         NSArray *coordinates = [self.mapView valueForKeyPath:@"annotations.coordinate"];



         CLLocationCoordinate2D maxCoord = {-90.0f, -180.0f};

         CLLocationCoordinate2D minCoord = {90.0f, 180.0f};



         for(NSValue *value in coordinates) {

              CLLocationCoordinate2D coord = {0.0f, 0.0f};

              [value getValue:&coord];

              if(coord.longitude > maxCoord.longitude) {

                   maxCoord.longitude = coord.longitude;

              }

              if(coord.latitude > maxCoord.latitude) {

                   maxCoord.latitude = coord.latitude;

              }

              if(coord.longitude < minCoord.longitude) {

                   minCoord.longitude = coord.longitude;

              }

              if(coord.latitude < minCoord.latitude) {

                   minCoord.latitude = coord.latitude;

              }

         }

         MKCoordinateRegion region = {{0.0f, 0.0f}, {0.0f, 0.0f}};

         region.center.longitude = (minCoord.longitude + maxCoord.longitude) / 2.0;

         region.center.latitude = (minCoord.latitude + maxCoord.latitude) / 2.0;

         region.span.longitudeDelta = maxCoord.longitude - minCoord.longitude;

         region.span.latitudeDelta = maxCoord.latitude - minCoord.latitude;

         [self.mapView setRegion:region animated:YES];  

    }