Ranged-vision hoppers

Reading a thesis paper on Map exploration and path planning through sonar sensor. Learnt about something knowna as the distance transform which might come in handy for calculating short paths to cells within the range of vision.

THe first problem is to decide the target cell within the range of vision. Should it be at the edge (in which case, I have only about half an idea about the place im hitting), or just before it (which could screw up the utility of the an already small range). And how dynamic should that target cell be (how fast do I update it as the bot hops).

As for the heuristic I was thinking of using some simple function, which are generally used with grid-maps for methods like A*. Amit Patel's heuristic page is pretty ok, and so is this for learning A*, and then this (Link to primary site) for learning about heuristics. In fact, Amit's page should be read after these two.