If generalized to 2D (and over the unit sphere), you'd get Google's S2 library (https://s2geometry.io/).

In 3D, the same can be done with morton codes (or a 3D hilbert curve) to build an implicit octree. Some raytracing systems use this for fast BVH construction.

In either case, this approach differs from mipmaps in that the underlying data can be sparse, and is simply stored in a sorted array.