In
geometry, the
stereographic projection is a particular mapping (
function) that projects a
sphere onto a
plane. The projection is defined on the entire sphere, except at one point: the projection point. Where it is defined, the mapping is
smooth and
bijective. It is
conformal, meaning that it preserves
angles. It is neither
isometric nor area-preserving: that is, it preserves neither distances nor the areas of figures.