title: How to change the color of an MKPolyline after rendering
body: <p>I have three lines which I'm drawing onto a map, all in the same way:</p>
  
  <pre><code>    MKPolyline *polyline = [MKPolyline polylineWithCoordinates:coordinateArray count:2];
      [self.mapView addOverlay:polyline];
      self.routeLine = polyline;
  </code></pre>
  
  <p>and: </p>
  
  <pre><code>- (MKOverlayRenderer *)mapView:(MKMapView *)mapView rendererForOverlay:(id &lt; MKOverlay &gt;)overlay {
  
      if ([overlay isKindOfClass:[MKPolyline class]]) {
          MKPolyline *polyline = (MKPolyline *)overlay;
          MKPolylineRenderer *renderer = [[MKPolylineRenderer alloc] initWithPolyline:polyline];
          renderer.fillColor = [UIColor statusGreen];
          renderer.strokeColor = [UIColor statusGreen];
          renderer.lineWidth = 5;
  
          if (overlay == self.routeLine) { 
              self.routeLineRenderer = renderer;
          }
  
          return renderer;
  
      }
  
      return nil;
  }
  </code></pre>
  
  <p>This is all working fine.</p>
  
  <p>After a few seconds I want to change the color of one of the lines:</p>
  
  <pre><code>(void) changeLineColor:(id)object {
       NSLog(@"changing color");
       self.routeLineRenderer.fillColor = [UIColor statusAmber];
  }
  </code></pre>
  
  <p>The method gets called and the renderer isn't nil, but the line doesn't change color. Feel I'm missing something fundamental, but not getting anywhere with the docs.</p>