Okay, it bugs me, I admit that. Every time I play.
The map has many interesting features. Mountains, oceans, grasslands, deserts, forests. Gameplay-wise, none of that means squat. Oh, to be fair, forest are slow to travel through and allow building of lumber camps. But that's it.
Historically, cities were founded on places with some convenience or importance. Next to bodies of water to allow trade and agriculture. On lowland fertile planes. Next to ore mines in the mountains. On the crossroads of important trade routes. Civilization series present this nicely, with each hex/square providing different resources, so what you see is what you get. Food on plains and grasslands, extra trade on rivers, production on mountains.
Why in the seven hells FE/LH uses a system where the quality of settlement points is absolutely disconnected from the map features, and instead repressented by arbitrarily chosen sets of numbers. Huge plain. You can get 4 food here, only one food on the spot next to it, and nothing at all two squares next.
WHY???
Oh yes, you can come up with many rationalization, like underground water, and magical gimmicks you can't see, but you know... it's wrong. From immersion and gameplay points of view, it just gives a strong impression of a duct tape hotfix.