private Bounds getBounds(String left, String right, String top, String bottom) {
		return new Bounds((left != null && left != "" ? Double.valueOf(left) : (double) -10),
				(right != null && right != "" ? Double.valueOf(right) : (double) 10),
				(top != null && top != "" ? Double.valueOf(top) : (double) 10),
				(bottom != null && bottom != "" ? Double.valueOf(bottom) : (double) -10));
	}