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Cahill Butterfly Map 1909
Cahill 1909
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Cahill-Keyes M-layout world map silhouette including Antarctica
Cahill-Keyes 1975
Why Cahill? What about Buckminster Fuller?

Evolution of the Dymaxion Map:
An Illustrated Tour and Critique

Part 9.5

by Gene Keyes

Summary: I love Bucky, but Cahill's map is a lot better. Here's how.

Click inside boxes to open other sections in separate windows.
1) Introduction and
Background Notes

2) 1943:
Split Continents

3) 1944:
Whole Continents

4) 1946:
The Dymaxion Map Patent

5) 1954
Whole Continents

6) 1967 ff:
Later Editions and
World Game Versions

7) 1995 ff
Dymaxion Maps
on the Internet

8) Notes on Scaling Dymaxion Maps
9) Critique:
Dymaxion Map Compared to Cahill

9) Critique: Seven Design Flaws of Fuller's Map as Compared to Cahill's
9.1) Layout assymetrical
9.2) Graticule irregular
9.3) Korea distorted
9.4) Scalability poor
9.5) Anti-metric edges
9.6) Globe fidelity poor
9.7-a) Learnability poor
9.7-b) Learnability poor
9.8) Conclusion

Part 9.5
Anti-metric measurements

I have already broached this problem in Part 8. Suffice to reprise here that Fuller's icosahedral not only snubs the metric system, but would do a poor job even if it tried to use it. The controlling true-scale icosahedral triangle edges have an unstated and irrational metric length of 7,048.89 km. Fuller, the old sailor, only gives distance in nautical miles, and those too have an irrational per edge distance of 3,806.

It is ironic that the patron of the whole-earth philosophy would shun the very measurement which itself derived from the whole-earth circumference, that 1/10,000th decimal portion of a quarter great circle, equator to pole.

Those irrational bases of the icosahedral map in turn lead to haphazard and irrational scales (e.g., 1/43,520,000) that do not neatly tie into metric lengths, as does 1/20,000,000 (to which I re-adjusted various examples in this set). Other Fuller maps have a medley of sui-generis scales such as  1/21,000,000, and 1/47,500,000 and 1/77,500,000, etc., and that's not including the second "shrunken" scale where mentioned.

The Fuller map therefore, unlike Cahill, has no chance to combine three fundamentals: of whole-earth elementary education:
1) a synoptic globe-plus-map pairing;

2) a metric understanding of the global basis of a kilometer and a meter and a millimeter;

3) a correspondingly easy-to-grasp set of rational metric scales such as 1/200,000,000 and 1/100,000,000 and 1/50,000,000 and 1/20,000,000, etc.
A Cahill map (and readily made cognate globe) would enable just such a three-fold teaching of geographic fundamentals:
• its obvious map-globe relation;

• its metric system tie-in;

• and its easily understood regular metric scales.

The anti-metric nature of the Dymaxion map in turn is symptomatic of its overall lack of fidelity to a globe, as elaborated next.

Go to Part 9.6
Poor to zero comparison with any equivalent globe

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Text cc. 2009 by Gene Keyes; Cahill-Keyes Map c. 1975, 2009  by Gene Keyes