This is an illustration of Dijkstra's and A* searches for finding a path from the start node A to the goal node B in a navigation problem.

The white (unfilled) circles represent nodes in the open set, i.e., nodes that are yet to be explored, while the black (filled) circles represent nodes in the closed set. Initially, A* progresses in a straight line toward the goal. Upon encountering an obstacle, it begins exploring alternative paths by expanding nodes from the open set until a viable route is found.

Symbols

• red number - g value, distance from A
• blue number - h value, heuristic, distance to B
• black number - f value, f = g + h
• hollow circle - the node in openlist
• black circle - the node in closedlist
• grey flashing border - path
• blue border - updated node as a result of a relaxation