Compromise and polyconic world projections: Natural Earth, Equal Earth, Robinson, Winkel tripel, Aitoff and Van der Grinten.
Raw projection maths, reached through Visualize.Geo.Projection.project/3 and
invert/3. project/4 takes longitude and latitude in degrees, already rotated and
centred, and returns unit-scale planar coordinates; invert/4 is its inverse. Scale,
translation and rotation are applied by the parent module.