It’s been a while since I’ve written a post for this project, but that’s not from lack of progress or activity — quite the opposite. In fact I’ve been repeatedly amending and revising a post for over a month now. Now it’s finally ready to share.

Planet Size

After the last article, I discovered that my calculations were a bit off. I’m not exactly sure why this is. I posted about this in the Facebook Mystara Cartographic Society (embedded below, if it’s working), and after discussions there (check the “Is my maths off in some way?” comment thread for details) decided to go with a round 36,000 miles for the circumference — primarily because chasing an exact 72 miles per hex was not working, and because this figure gives an easy 100 miles per degree.

Unfortunately, this didn’t work out either — it ended up giving far bigger hexes than I had expected, with 24 mile hexes coming out at 26 miles.

So I left it for a month or so. And then it hit me: I can reverse-engineer the circumference from measurements in Illustrator.

Basically, what I did was measure a hex, then divide the circumference by that number. Then I multiplied that by the desired hex size, which gave the actual circumference I needed to define the ellipsoid.

It turns out that Atlas Mystara has a circumference of 33,032 miles, which is quite a bit smaller than previous estimates. But this indeed made the measurements for hexes come out nearly perfectly in Illustrator, so I’m locking this in as our final circumference for the new 2018 model.

Phew! Now I just have to go back and re-georegister all those maps. Thankfully I already know how to do this without losing all the GIS data I’ve been inputting, and it’s not very hard.

As a consequence of all this, I have had to rebuild the model yet again — hopefully for the last time!

Oops… Looks like I spoke too soon…

Revisiting the Hollow World