Hex9: A Quasi-Authalic, Quasi-Continuous Hexagonal DGGS on the Reference Ellipsoid

Hex9 is a novel discrete global grid system (DGGS) that prioritises geometric coherence, leading to a unique hexagonal hierarchy with aperture 9 refinement. This system allows for a quasi-continuous addressing scheme that recovers points on a reference ellipsoid to arbitrary precision without relying on a prior coordinate reference system. Its design is projection- and ellipsoid-independent, with a separable geometric realisation that achieves quasi-uniform cell areas on WGS84.