Map projections
A map projection (MP) is comprised of
a. a connected region of the surface of an oblate ellipsoid, b. a generating projection, and c. an MP range in 2D coordinate-space,
where:
d. the MP range is connected, and e. the generating projection is one-to-one from the region of the oblate ellipsoid onto its MP range and its inverse function is smooth and orientation preserving.
Map projections are 2D models of a 3D curved surface.
The generating projection is formulated in terms of surface geodetic coordinates called mapping equations.