A panoramic photo is capable of showing a 360° angle-of-view all around. Such an image is difficult to print and see as a whole due to its extreme aspect-ratio. One way to show everything at once is to transform the panorama into a wee planet. This creates an unusually interesting image that looks like a small planet shot from above using a fisheye lens.
Helderberg Photographic Society 
Hi Steve,
This article is a little misleading in that the polar coordinates method in Photoshop is not really a stereographic projection – it is actually just remapping pixels of an image on a 2D level and gives quite different results to a true stereographic projection on the same image.
Regards, Peter Höhsl
That may well be a sticking point for mathematicians but I don’t think it matters for photographers that simply want to follow the steps and learn how to make little planets.