A map projection which is a conformal mapping, i.e., one for which local (infinitesimal) angles on a sphere are mapped to the same angles in the projection. On maps of an entire sphere, however, there are usually singular points at which local angles are distorted. The term conformal was applied to map projections by Gauss in 1825, and eventually supplanted the alternative terms "orthomorphic" and "autogonal". No projection can be both equal-area and conform, and projections which are neither equal-area nor conformal are sometimes called aphylactic.