public void addMarker(final InfoMarker marker) {
   double easting = marker.getLonLat().lon();
   double northing = marker.getLonLat().lat();
   markersPositions.put(easting, northing);
   markerLayer.addMarker(marker);
   markersOnMap.add(marker);
 }
 public void applyFilterToStationsOnMap(String filterCategory) {
   clearMarkerLayer();
   for (InfoMarker marker : markersOnMap) {
     if (marker.getStation().hasStationCategory(filterCategory)) {
       markerLayer.addMarker(marker);
     }
   }
 }