Craster’s discarded projections

[mapnerd2022]

Didn't Putnins independently rediscover also Craster's Hyperbolic and Elliptical projections?

[mapnerd2022]

Since Craster rejected those two and made them resemble the basic sinusoidal, just like his parabolic which is a marginally less distorted version of the basic sinusoidal projection. I have read John Snyder's 1977 paper on the various Pseudocylindricals and I've wondered about that.

[daan]

Didn't Putnins independently rediscover also Craster's Hyperbolic and Elliptical projections?

It would just be speculation to answer, but it would not be surprising if he had. Putniṇš, Wagner, Craster, and Kaivraiskiy (and probably othes) were all messing around with basic curves in equal-area, pseudocylindric projections at about the same time — and in fact, Snyder changed his attribution of two of the Putniṇš projections to Wagner after uncovering them in earlier materials.

— daan

[PeteD]

Didn't Putnins independently rediscover also Craster's Hyperbolic and Elliptical projections?

Are you saying that Putnins P2 and P6 are rediscoveries of Craster's elliptical and hyperbolic projections, respectively?

[mapnerd2022]

Didn't Putnins independently rediscover also Craster's Hyperbolic and Elliptical projections?

Are you saying that Putnins P2 and P6 are rediscoveries of Craster's elliptical and hyperbolic projections, respectively?

Yes, if you mean the pointed polar equal area versions.

[PeteD]

I do. The even numbers are all equal-area, and the Putnins projections with a pole line are denoted with a prime symbol (often rendered as an apostrophe).

Do you have a citation for this?

[mapnerd2022]

From Snyder's 1977 paper:«Craster, in developing his parabolic
pseudocylindrical, also derived and rejected a projection with hyperbolic meridians. The graticule of meridians and parallels was intentionally very similar to that
of the sinusoidal, but formulas were far
more complicated.»

[PeteD]

Is that this paper? Unfortunately, I don't have access.

Craster, in developing his parabolic pseudocylindrical, also derived and rejected a projection with hyperbolic meridians. The graticule of meridians and parallels was intentionally very similar to that of the sinusoidal, but formulas were far more complicated.

That's a good enough reason for rejecting it, I suppose. Craster's elliptical projection wouldn't have been so similar to the sinusoidal but would have been very similar to Siemon IV and the Boggs eumorphic. Does the paper give Craster's reason for rejecting his elliptical projection?

[mapnerd2022]

Unfortunately, no.

[mapnerd2022]

But Snyder does actually point out that the P2 projection is graphically similar to the Eumorphic, hence why I think that even the P2 was independently presented by Putnins in 1934.