Hollow World Set Maps Revisited I

Before we continue with the 3D model and choosing a placement, I think it’s time to take a closer look at the Hollow World Set world maps.  This treatment is going to get long and complicated, so I’m going to split it up and present it over the next few days.

The Hollow World Set came with world maps for both worlds, inner and outer, in a pseudo-Robinson projection.  I’ve already mentioned the problems with the Outer World map, but it’s worth going over them again now.

Hollow World Set Outer World map

The Hollow World Set Outer World map

The Hollow World Set Outer World map

The world maps in this set were full of detail, in terms of both place names and overall terrain, making them invaluable sources for expanding the hex maps.

The main problem with this map is that it stretched the Master Set map’s coastlines out in order to fill up the pseudo-Robinson projection grid.  In so doing, it broke the connection with the hex maps, which of course remained unstretched (since they were based on the Master Set map).  This was all done by hand, of course, and it turns out they did a really excellent job of it, as we’ll see in a moment.

But before we can compare these maps, there’s something we need to do: we need to return the map to a standard latitude/longitude grid, aka an Equirectangular or Plate Carrée projection.  (This seems like the most likely projection to assume for the Master Set map and the hex maps, because it’s just a regular grid, with all the cardinal directions where they should be.)  I actually did this some years ago.

I used a GIS program called Manifold to do this.  First, I added extra latitude and longitude lines to the map, so that it had a line for every 10º.  Then, I painstakingly added a control point to every single intersection:

Hollow World Set Outer World map with control points

Hollow World Set Outer World map with control points

703 points in total — it’s not a terribly fun job… But when it’s done, you can then georegister the image and change the projection, pulling the pixels into new patterns based on the control points.

Here’s the result of changing it to Equirectangular projection:

Hollow World Set Outer World map in Equirectangular projection

Hollow World Set Outer World map in Equirectangular projection

This is the projection needed to drape the map on a 3D sphere.  It must be in a 2:1 ratio, or it will not cover the whole sphere.  That’s essentially the problem the designers were facing when they decided to stretch the coastlines.  (And in Mystara’s case, the polar openings mean that a 2:0.9 or 2:0.8 ratio is needed to cover the regular spheroid/ellipsoid areas of the planet’s surfaces.)

Now compare this with the full extent of hex maps we’ve assembled so far, and the stretching should be quite obvious:

Lining Up Mystara hex maps, 20th February 2016 Progress Snapshot

Lining Up Mystara hex maps, 20th February 2016 Progress Snapshot

Here’s what happens when we overlay this:

Outer World hex crawl overlaid on Hollow World Set map

Outer World hex crawl overlaid on Hollow World Set map

Note the stretching of the hexes east-west, or the north-south squashing if you prefer.  The hex maps would need to be changed quite drastically to fit.

Also note, however, that the fit is actually pretty good.  Let’s squash the map and overlay it with Master Set coastlines to see just how good a fit it is:

Master Set coastlines (in red) with Hollow World Set map squashed to fit

Master Set coastlines (in red) with Hollow World Set map squashed to fit

I’d say that’s pretty amazing for a reprojection done completely by hand.  Once again, awesome respect for the original artists who did the cartography on these maps!

Now let’s do some analysis.  I’ll try and keep it short and sweet.

  1. The Outer World latitudes were squashed to fit the projection template, but the land itself is mostly compatible with the Master Set version.
  2. The regions from 60-90º especially were shown smaller than the rest of the map.  This was likely done to represent the approach to the polar openings, but the precise configuration remains vague.  Notably, the land shapes are not different from the Master Set — they haven’t been squashed or stretched.
  3. The regions that were cut off past 90º were placed in the polar openings on the polar opening maps in the Hollow World Set.
  4. However, the latitudes on this map will not fit with our model, as shown in my exploration of Placements 1-3.  They are also quite radical, placing Alpha at about 63ºN, which I think most will agree is too far north.
  5. The longitudes can all be safely ignored too, due to squashing.
  6. We can cut this map up in this squashed state and use it as a source to expand the hex maps.

That’s about it, I think.

Next: the Hollow World…