public double calcPathWeight(Path path) {
		double total_weight = 0.0;
		Point p;
		for (int i = 0; i < path.size(); i++) {
			p = path.get(i);
			// TODO: check if weighted by weight or source values (probable weighted, right?)
			total_weight += _map.getSource(p.x(), p.y());
		}
		return total_weight;
	}