/**
  * Renders the map javascript ground overlays
  *
  * @param Ivory\GoogleMapBundle\Model\Map $map
  * @return string HTML output
  */
 public function renderGroundOverlays(Map $map)
 {
     $html = array();
     foreach ($map->getGroundOverlays() as $groundOverlay) {
         $html[] = $this->groundOverlayHelper->render($groundOverlay, $map);
     }
     return implode('', $html);
 }