Creating a World - Dodecahedral Base Map

[Axelton]

Hello! I have been working on creating a geofiction for awhile now, slowly but surely, and am STILL trying to nail down "the perfect" world map, which for obvious reasons is required before many other things. As far as the geography goes, I'll be focusing on making a detailed and semi-realistic (feeling) heightmap, biome map, weather patterns, flora/fauna coverage, mineral and resource maps.. etc. Basically everything "natural" before humans start to emerge and create civilizations, having the previous information will help predict culture and progress of human civilization on said planet.

So now that you hopefully understand what I hope to achieve, let me get to the issue I have been trying to work out. Thus far I have been working in Equirectangular projection, and importing that image into G.Projector and a round-planet model in SketchUp (I forget where I found the tutorial for that, someone made it specifically for viewing Equirectangular on a globe). This takes some going back-and-forth to map the polar areas, and I have been using G.Projector to convert the map to an Equirectangular Oblique in order to help map the poles. So in short, I have figured out a way to create a very rough approximation of the geography on the entire globe, be it a bit of a pain. But when projecting the "Base" equirectangular map onto a globe, there is of course a lot of blurriness in the polar regions, due to the map distortion. So what I have been wanting to do is find a way to have my "Base" map be a Gnomonic Dodecahedron (possibly Icosahedron, but Dodecahedrons pentagons are nicer to look at than the smaller, if a bit less distorted, triangles of the Icosahedron.) Reason being, I can have the same amount of information on all faces of the planet, though I realize there is distortion involved, I feel it would be easier to deal with than Equirectangular, or other projections, distortion.

I have no idea how to even begin creating a Dodecahedral map, as my current map is in Equirectangular, and G.Projector does not seem to have an option other than Cubed Gnomonic. I also plan on using this "Base information" map to, in the future, create "nice looking" maps of various aspects such as political or natural, and in various projections. This is initially why I have been using Equirectangular, as G.Projector uses it as in input, and I could use the converted projections it gives me as a map to trace. Though my issue is converting my Equirectangular into a Dodecahedral projection, and vice versa, in order to have the open possibility of converting to other projections.

So how do you go about converting Equirectangular, or any other projection, into Dodecahedral Gnomonic? If anyone has any suggestions on whether or not using this Dodecahedron method would be useful, or more of a pain than other methods, please let me know. If anyone has any suggestions on better methods on how to go about this, I would love to hear it aswell! Thanks!

[johnvanvliet]

i would use python

and a quick google search has this page with some python code
older page from 2012
http://www.chiark.greenend.org.uk/~sgtatham/polypics/