Let's map the moon.
Circles are the simplest shape for our eyes and brain to understand. When faced with a swathe of circles, we're not as overwhelmed by the information. It's easy to look at, and easy to read.
Not only do circles create a contained space, but they also imply entire worldliness. In old times, a village was often mapped in a circle, which was probably the whole world to its inhabitants.
Black ink on white paper. Letterpressed.