# Stereographic Projection

Here you see how the stereographic projection of the earth onto a plane is obtained. For each point on the surface, a ray from the north-pole through this point is constructed. The intersection of the ray with the plane is the projected point.

##### Controls

You can press R to show the ray from the north-pole through the earth to the plane.

If you press I the sphere is reversed. Mathematically, this corresponds to the map $z \mapsto \frac{1}{z}$ on the Riemann Sphere.

With A and B you can adjust the height of the earth.

If you have a spherical camera (such as the Ricoh Theta), then you can also switch to the camera input feed via C and use the spherical footage instead of the earth.

##### Software: CindyJS

Deformation made possible by connecting CindyJS to WebGL and calculating transformations on the GPU.

##### Widget Author:

Aaron Montag, Texture from http://planetpixelemporium.com