Quote Originally Posted by StickGrinder View Post
EDIT: mmmh, looking at the picture I think I got the point: I didnt take into account more spacing between poles profile and image border. In fact north pole continent should be wider; the same is for the sea area surrounded by isles in the south. I'll try to fix this!
It's a fundamental problem with the Equidistant Cylindrical projection you are using. Anything that would look right on a globe is going to look squashed/stretched progressively more and more toward to poles, and vis versa. That's one of the reasons the projection isn't used much except where its simplicity outweighs its problems.

All projections have distortion, but by choosing projections carefully you can minimize its effects on your map's intended purpose. If you want shapes generally preserved, a conformal projection what you want, like Mercator or Stereographic. Sinusoidal, Hammer, and Mollweide are equal area options that keep things the same size relative to one another. Equal Area Cylindrical projections like Gall-Peters are particularly ugly so you should probably avoid them. If you want to balance different kinds of distortion out, then a hybrid projection is best, like Winkel Tripel or Robinson, though they often have a rather "modern" look to them.

Switching to any of these would require some editing of your map to fix the distortion. Reprojecting would preserve the distortion (As you can see in RobA's polar azimuthal projections) while simply declaring the map to be in another projection wouldn't work as the map is the wrong shape (Mollweide for instance is elliptical) so you'd have to clip off or fill in bits and then line things back up along the edges.