Ahahaha oh wow what the forget. My mind so blown right now. I feel like I've discovered some ancient forgotten ninjutsu here. I was loving around with the new UV mapping method I discovered and though, why not try to make the earth cube again. I've done a few in the past but have always had seams and some stretching. I did my magic and boom motherforgeter. Pixel loving perfect sphere to cube UV map.
I can't stress enough that I have actually spent over 12 hours researching and working on this stuff. Reading about cartography and UV mapping theory, guides, and stuff. Hell I even studied real map projections and their math. I was scavenging the web for all kinds of programs for converting maps from one projection to another and few worked or they were expensive as forget and watermarked.
No seams. There is a little fuzz on the poles for some reason but that can be easily removed in an image editing program.
http://img690.imageshack.us/img690/6299/holystuffsr.pngOrthographic view from the side:
http://img812.imageshack.us/img812/6273/whatthefp.pngThere is some pixel stretching because the vertices of a sphere and a sphere made from a cube don't match 100%. If they would the texture would be 100% pixel perfect. That would be amazing.
The earth texture from which I baked the cube is 4096x2048. That is the small version. I have a 10800x5400 of that texture. I can bake some seriously high loving res textures with this method.
Blender is magic. I feel like a boss.