Cahill-Concialdi conformal projection?

[Fil]

Refs:

• https://blog.map-projections.net/four-polyhedral-projections
• https://www.mapthematics.com/forums/viewtopic.php?f=7&t=557&p=869

[TJung1968]

I think the Cahill-Concialdi would be a great addition! There’s one thing that I didn’t make clear in my blogpost (but I’m going to add a little note): It’s a rearrangement of Cahill’s conformal butterfly map which is mentioned on Gene Keyes’ website. I think Mr. Keyes is in possession of the original formulae of the Cahill Conformal (which were provided by Oscar S. Adams). Since I’m currently in contact with Mr Keyes anyway, I’m going to ask him about that.

[cahill-keyes]

As TJung1968 mentioned above, for more details on the Cahill Conformal and its derivatives by Gene Keyes, and Jacob Rus, see http://www.genekeyes.com/CAHILL-VARIANTS/Cahill-Conformal.html

I did indeed xerox the Oscar Adams tables in 1983 at the Cahill Archives in the Bancroft Library, U.Cal.Berkeley, but the copies' legibility was very poor. However, I think the Conformal neo-Cahill remake by Jacob Rus [i.e., in a Cahill-Keyes frame] is superior, for all the reasons I've been propounding since 1975: http://www.genekeyes.com/Redesigning-Cahill.html

The C-K is not conformal, but has a hand-calculated graticule of "proportional geocells". Its precursor came about when I began to re-arrange Cahill's 1928 Conformal Butterfly Variant:

[Fil]

(I've updated the reference image because the previous one had somehow disappeared.)

[seav]

@jkunimune15 has a Java implementation of the Cahill-Concialdi projection and I was able to port the forward projection code into JavaScript (though not the inverse projection).

[curran]

Here's a really nice variant I found on the website of @cahill-keyes :

From http://www.genekeyes.com/