@Override
	public void propertyChange(PropertyChangeEvent event) {
		for (AbstractMarkerModel model: this.markerModels) {
			model.propertyChange(event);
		}
		
		String property = event.getPropertyName();
		if (property.startsWith(Global.ZOOM)) { 
			do {
				this.clearChanged();
				organizeMarkers();
			} while (hasChanged());
			setChanged();
			notifyObservers(Global.MARKERS_UPDATE); 
		}
	}