Thursday, November 17, 2011

What’s your favorite map projection?


What’s your favorite projection? And what does that say about you? Cartoon by Randall Munroe, from: http://xkcd.com/977/

OK, a number of you guys sent me this link to a pretty humorous cartoon which lampoons the various map projections, so I figured I may as well make an official blog posting about it!  According to the premise of the cartoon, the map projection that you prefer supposedly indicates what sort of person you are, or at least gives certain clues about your personality.  I like that better than astrological signs.  And it just might be more accurate.  Uh oh!  I’m in trouble.  I am attracted to the Waterman butterfly projection! 
If you mouse over the cartoon on its original website, the bubble shows up with the text “What’s that?  You think I don’t like the Peters map because I don’t like having my cultural assumptions challenged?  Are you sure you’re not:: ….puts on sunglasses:: ….projecting?”
Thanks, Jonathan Halabi, Diana Morgan, Keith Miyake, and kuschk (The Basement Geographer) for sending the link. 
Here’s another something about the Waterman butterfly projection, which is based on the 1909 Cahill projection, shown above. “From the cover of 1919 pamphlet by Cahill,The Butterfly Map.’  His 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.
“The Waterman ‘Butterfly’ World Map Projection was created by Steve Waterman and published in 1996.  It is an octahedral transformation of a globe, reviving the butterfly map principle first developed by Bernard J.S. Cahill (1866–1944) in 1909.  Cahill and Waterman maps can each be shown in various profiles, typically linked at the north Pacific or north Atlantic oceans.
Whereas Cahill's approach was that of an architect, Waterman derived his design from his work on close-packing of spheres.  This involved the interpretation of a spherical extraction from cubic closest packed spheres, into a corresponding convex hull. Then for its projection; straight lines were used to define each 5 × 5 section onto this convex hull.
Projection employed an equal length delineation approach for the equator.  Latitudes were drawn in three straight line sections (in each octant): from pole to fold-line, fold-line to largest line parallel to equator, and then from there to the equator.  The largest line parallel to the equator also has equal length delineations.  One particular Waterman polyhedron best served to minimize land sinuses (breaking up of land masses) and was therefore chosen.
Like Buckminster Fuller's 1943 Dymaxion Projection, an octahedral butterfly map can show all the continents uninterrupted if its octants are divided at the proper meridian, that is, 20° W, and joined, for example, at the North Atlantic, as in the 1996 version.”

            Here is a really nice critique of the Waterman projection, with some suggestions for improvements: http://www.genekeyes.com/WATERMAN-REVIEW/Waterman-review.html
Gene Keyes hand-drawn version of the Keyes-Cahill map.  From: http://www.genekeyes.com/Cahill-Keyes-2.html

Waterman’s own site, at http://www.watermanpolyhedron.com/, has results on his 20+ years of research on the “close-packing of spheres,” PLUS original theories in theoretical physics! 


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