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B.J.S CAHILL'S BUTTERFLY MAP AND BEYOND:
A COMPARATIVE GALLERY OF OCTAHEDRAL WORLD MAPS
Compiled by Gene Keyes
First edition, 2007-06-05
Thumb Index
Each item opens in a separate window.
If you have a tabbed browser, you can open some or all of the maps in separate tabs, then easily compare by toggling among them.
N.B.: each map has been converted to a Comparison Scale of 1/200 M, either by enlarging or reducing the source image. (To a span of 100 mm across the outer meridians of a 4-octant subset.)

Geocell size is also specified. (In 1983, I coined the word "geocell" to designate a one-degree unit of latitude and longitude.)

Each image here cites a "defining meridian", which enables unbroken continents if the octants follow from that given longitude. Cahill's master stroke was 22 1/2° W, but it resulted in geocell assymetry: too many half-degree units throughout. So 20° W is preferable for a Cahill-inspired map. Other division-longitudes miss the point, and break up continents, e.g., Harrison, and Anderson, below.

Besides collecting scattered images of the Cahill map or derivatives, this gallery also indicates some sub-standard reproductions. Erroneous examples are marked "X": see notes within.

This is not a complete listing; check back for updates.

1909 Cahill Original
 1913 Cahill rubber ball globe~map
 1914 Cahill-Denoyer
 1919 Cahill
 1920 Cahill M-shape S. Pacific
1934 Cahill 3-in-1
 1934 Cahill M-shape
 1938 Raisz
 1944 Hood
 1962 Dahlberg X
1975 Cahill-Keyes
 1975 Harrison X
 1976 Lee Conformal
 1996 Furuti Gnomonic
 1996 Furuti Gnomonic Truncated
1996 Waterman
 1996 Waterman
ODT, biggest
 2001 Furuti Gnomonic AVHRR
 2001 Furuti Gnomonic Remote
 2001 Furuti Gnomonic USGS
2002 Anderson Conformal X
 2002 Anderson Gnomonic X
 2002 Anderson Equal-area X
 2006 Parry [Furuti] Gnomonic
 2007 Moore (Furuti) Gnomonic

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2007-06-05