Bernard J. S. Cahill

Bernard Joseph Stanislaus Cahill (London, January 30, 1866 - Alameda County, October 4, 1944^[1][2]), American cartographer and architect, was the inventor of the octahedral "Butterfly Map" (published in 1909 and patented in 1913^[3]). An early proponent of the San Francisco Civic Center, he also designed hotels, factories and mausoleums like the Columbarium of San Francisco.

Cahill butterfly, conformal version of the projection. 15° graticule, 157°30′E central meridian.

From cover of 1919 pamphlet by Cahill, "The Butterfly Map", 8 p.

His polyhedral Butterfly World Map, like Buckminster Fuller's later Dymaxion map of 1943 and 1954, enabled all continents to be uninterrupted, and with reasonable fidelity to a globe. Cahill demonstrated this principle by also inventing a rubber-ball globe which could be flattened under a pane of glass in the "butterfly" form, then return to its ball shape.

A variant was developed by Gene Keyes in 1975, the Cahill–Keyes projection.

See also

• World map
• Waterman butterfly projection
• Octants projection
• Cahill–Keyes projection