protected void defineWorld(int worldType) {
        world = new HashMap<Position,Tile>();
        for ( int r = 0; r < GameConstants.WORLDSIZE; r++ ) {
            for ( int c = 0; c < GameConstants.WORLDSIZE; c++ ) {
                Position p = new Position(r,c);
                world.put( p, new StubTile(p, GameConstants.PLAINS));
            }
        }
    }