a square area with a grid on it when looped horizontally and vertically becomes a torus, and you cant massage that into a sphere.

geometrically speaking, you can't map a square grid onto a sphere like that without a lot of distortion.

if you have to use a square grid, you can put the distortion at the poles like latitude and longitude.

another way is using cube mapping, sort of like a rubiks cube that has been inflated, but you will have 8 points of strong distortion, or start with another shape instead of a cube to tessellate with less distortion.


http://www.evilbastard.org/slight/tesselation.gif

whatever way you do it, assuming youre matching it up with a 2d array, you're going to have seams and stuff to deal with.

can you be more specific what you want to do with the sphere?