Create Overlayview for set of rectangles..

// the data representing the route. 
MKPolyline* _route;
MKPolylineView* _routeView;

// Following lines create polyline for my coordinateArray, add into overlay, and make it visible on map
self.route = [MKPolyline polylineWithCoordinates:coordinateArray count:points.count];
[self.mapView addOverlay:self.route];
[self.mapView setVisibleMapRect:[self.route boundingMapRect]];
     

- (MKOverlayView *)mapView:(MKMapView *)mapView viewForOverlay:(id <MKOverlay>)overlay
{          
    if ([overlay isKindOfClass:[MKPolyline class]])
    {
     self.routeView = [[[MKPolylineView alloc] initWithPolyline:self.route] autorelease];
     self.routeView.fillColor = [UIColor redColor];
     self.routeView.strokeColor = [UIColor redColor];
     self.routeView.lineWidth = 8;
     return self.routeView;
    }
    return nil;
}