How can you use the map to argue that alexander was not great?

You need a before / after set of maps.
It is one thing to conquer and create an empire. 
It is quite another to occupy the land you've conquered and hold on to it.
Alexander did not name a successor. He died when he was only 33 (? google this) and those closest to him destroyed the empire he had created by squabbling among themselves. 

Check google mate it's easy