A* heuristic, overestimation/underestimation?

Question

I am confused about the terms overestimation/underestimation. I perfectly get how A* algorithm works, but i am unsure of the effects of having a heuristic that overestimate

Answer 1

As far as I know, you want to typically underestimate so that you may still find the shortest path. You can find an answer quicker by overestimating, but you may not find the shortest path. Hence why overestimation is "incorrect", whereas underestimating can still provide the best solution.

I'm sorry that I cannot provide any insight as to the birdview lines...