I previously noted a simple method I’ve used for quite a while to note the location of something within a hex when a detail map isn’t really needed. I’ve always used the 3-subhex-across approach I displayed in that post, figuring that, whatever the size of the hex, dividing it into sevenths (or so) would be close enough for the sort of medium-level detail this approach provides. However, my current project is going to utilize 5-mile hexes, and in trying to decide how to designate 1-mile hexes on detail maps, I’m wondering if using a similar approach might not work:
So if I’ve got a detail map of hex 171,092, the 1-mile subhex in the center would simply be labeled 171,092A.
I’m not sure about this, and it might just be better to give each detail map it’s own set of numbers. But this would have the advantage of the detail map coordinates being directly tied to the overview map coordinates. It also leaves the question of what to do with the subhexes at each corner of the large hex.