Maps use the same convention for directions.
Historically several conventions were used to set directions on maps. Different conventions pointed to different directions. This is an old compass and an old map:
However all the ancient conventions faded except one. Today all maps use the same convention: Up is North, right is East, left is West and down is South. This means if you are standing then the sun rises to your right and the sun sets to your left, you are facing North and behind you is South.
However 1400 years ago this was portrayed in the Quran:
[Quran 18:17] You would see the sun, when it rose it shone into their cave from the right, and when it set it shone from the left, as they lay in the midst of the cave. That was one of Allah's wonders. He whom Allah guides is truly guided; but he whom He misguides, for him you will find no directing friend.
If the sun rises to your right and the sun sets to your left then definitely you are facing North, and behind you is South. This is the same convention used today in all maps.
How could an illiterate man who lived 1400 years ago have known which convention will prevail?