[ctimitkr] Sea level origin

Plot elevations of every point on earth in spherical coordinates.  The 2 angular coordinates remain the same, but make the radial coordinate the distance above or below sea level, not distance from the center of the earth.  This will cause areas below sea level, especially ocean floors, to poke through the origin and out the other side.  Maybe only do one hemisphere at a time, or omit below-sea-level points.  Let sea level be adjustable.

Inspired by spherical harmonics and electron orbitals, in which negative radii come out the other side.  (Previously.)