Description
World projected conformally into an octahedron arranged as a “butterfly”.
Classifications
polyhedral
conformal
Graticule
Meridians: Complex curves except for the edges and central meridian of each facet.
Parallels: Complex curves except for straight edge at base of each facet.
Origin
Bernard J.S. Cahill proposed three versions of the same basic butterfly arrangement, beginning in 1909. This is the conformal version, with mathematics for it developed by Oscar S. Adams ~1929. Cahill touted this version for meteorological purposes.