I think it's that the layout of the map, with flags going above and below a circular plane, looks exactly like (and is perhaps inspired by) the scanner that sho

I think it's that the layout of the map, with flags going above and below a circular plane, looks exactly like (and is perhaps inspired by) the scanner that shows where ships around you in local space are in Elite/Oolite (FOSS Elite 1984 clone, highly recommended).