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atimholt
11-15-2009, 04:30 AM
This post is kind of long for an intro, but it details why I came to this site. I'll post in more relevant forums when a couple little relevant projects are farther along.
Hello. I'm interested in maps because I'm writing a book. I'd been wary, until recently, of making a map for it because it ranges all over the globe of its fictional world (I didn't want to worry too much about distortion, especially with how they'd mess up sub-orbital ETA calculations) , but then remembered a couple things I learned from Calculus, 3d game programming, and the capabilities of my graphing calculator. Projecting the surface of a sphere onto a cube (well, actually the reverse) was presented as a good way of getting relatively minimal distortion as regards textures on a sphere, and is easy to do even by hand, if your doing a single point. That, and my globe has no major ocean through which to break, so I'm doing a "cube" projection; 6 gnomonic projections. For local city maps, using a little bit of 3D matrix transformation (and excel, and my wonderful calculator which does all my matrix multiplication for me) I'll use a gnomonic projection with its tangent point in the center of the map.
So, all in all, I'm enthusiastic about maps for the moment because I can finally map my world without hesitation. I'll say more about it when I've got the math all figured out, so I can post the spreadsheets for anyone to use.

icosahedron
11-15-2009, 06:26 AM
Hi Atimholt, welcome to the group.

Just an idea, but before you go too far down the route of your cubic globe, a standard mapping trick used in the gaming world is to map to an icosahedron (no special bias, honest). ;)

The projection here is similar to an interrupted sinusoidal, and will have less distortion than a cube. Because it is a 'standard', there is software available (some of it possibly free) that will take your map and convert it directly to icosahedral format, saving you a lot of calculator time.

I'm sure there are many people here who can help and advise you on all aspects of mapping, right from initial planning. You don't need to go it alone. :)

Gandwarf
11-15-2009, 06:38 AM
Welcome to the guild!

Redrobes
11-15-2009, 07:12 AM
Hi and welcome,

Iso is right about the iso. There are two or three good free bits of software able to re-project a map into a different map projection. I cant remember what they are now tho but it has come up a few times.

A sphere onto cube is not too bad to do the math yourself but it does give a fair bit of distortion. Iso less then progressively less as you go to a more curved space. Have a search around for projections and also wikipedia has some good info on them all too.

Steel General
11-15-2009, 09:23 AM
Welcome Aboard!

All that geometric mish-mash is beyond me but I'm sure it will get you what you need :)

NeonKnight
11-15-2009, 12:59 PM
Welcome to the Guild!