Another method how to reduce the amount of the examined cells is Jump Point Search (JPS) [32], which can be directly applied on A* algorithm. The principle of this method is the cropping of neighborhood cells in the surroundings of actually evaluated cell. The principle can be demonstrated on simple example in Fig. 5. Let the a denotes the actually evaluated cell and the arrow marks denote the movement from the previous cell. Then the grey unoccupied cells can be cropped, because they can be reached from the previous cell without the need of entering the cell a. The remaining cells (white color) are called natural neighbors. In ideal case, only natural neighbors are taken into account for path planning. The example in Fig. 5 has no obstacle cell. Obstacles in JPS create the forced neighbors (Fig. 6). These neighbors are created, because some cells cannot be cropped due to the blockage of alternative paths to the cells.