public void astern(Map nodes, Node start, Node ziel, Karte map)
    {
    	ArrayList<Node> open = new ArrayList<Node>();
    	ArrayList<Node> closed = new ArrayList<Node>();
    	open.add(start);
    	Node elem = start;
    	while ( !closed.contains(ziel) )
    	{
    		if ( closed.contains(elem) )
    		{
    			// ignore
    		}
    		else 
    		{
    			if ( elem.get_height() > 0  )
    			{
    				if ( open.contains(elem))
    				{
    					if ( elem.getF() < elem.getPredecessor().getF() )
    					{
    						
    					}
    							
    				}
    				else
    				{
    					open.add(elem);
    					elem = elem.getPredecessor();
    				}
    			}
    			else
    			{
    				// ignore
    			}
    		}
    	} 
    }