Nothing springs to mind. The problem is that location on any surface is a 2 dimensional parameter. However, two coordinates before any kind of "processing" defi

Nothing springs to mind. The problem is that location on any surface is a 2 dimensional parameter. However, two coordinates before any kind of "processing" define location on a plane. All spherical coordinate systems are therefore isomorphic to map projections, where the coordinates are simply a cartesian location on the flat map. And no map projection avoids singularities.