Blogger Uninspired Writers did a recent post on world building via creating maps. It directly focuses on fantasy worlds, but even in real world settings with fictional places, they can be useful.
If your drawing ability is limited, like mine and obviously many others, draw it in pencil first. That allows for easier changes or corrections as you go. Once you are reasonably satisfied, you can ink over in a darker color to make it more ‘permanent’.
You can also draw maps of buildings (rooms inside, room layout, etc.) or spaceships to make it easier to move people around inside them.
see the full post at: