Little planet — where it appears
Named by 2 essays across one field — each of them below, with the objects they name alongside it.
Stereographic keeps every angle, and only stereographic
One surface in the family preserves shape exactly — every right angle stays a right angle and both its arms are magnified equally, to the last bit the arithmetic has. It also sends every circle in the world to a circle in the picture, which the site's existing conic fit can be pointed at and asked to confirm without being told what it is looking at.
Conformal is not undistorted
The most distorted-looking picture in ordinary circulation is the little planet — a 360 photograph re-projected from below, with the ground curled into a ball. Its worst angular error over 160 degrees of the sphere is 4.4e-8 degrees, which is arithmetic noise. Every crossing in the original crosses at exactly the same angle in the result, and what has gone is area, over a factor of 255.
Named alongside it
The objects these essays reach for when they reach for this one.
AnisotropyCircle preservingConformalEquirectangularfield of viewStereographic projectionArea scaleConic fitDemonstrationEqual area projectionFisheyeJacobian