PageWithMap.php

public function MapWithDataList() {
    $flickrPhotos = DataList::create( 'FlickrPhoto' )->where( 'Lat != 0 AND Lon !=0' );
    if ( $flickrPhotos->count() == 0 ) {
      return ''; // don't render a map
    }

    $map = $flickrPhotos->getRenderableMap();
    $map->setZoom( $this->ZoomLevel );
    $map->setAdditionalCSSClasses( 'fullWidthMap' );
    $map->setShowInlineMapDivStyle( true );
    if ( $this->ClusterExampleDataset ) {
      $map->setClusterer( true );
    }

    return $map;
  }