[Proj] Relationship between transverse Mercator algorithms

[Irwin Scollar]

>Relationship betweeen transverse Mercator algorithms
>by Charles Karney

I have never read such a clear and concise 
explanation of the differences and similarities 
between the various TM algorithms.  Thank you!

As for good old Krüger 1912, considering that 
things were done those days using paper and 
pencil, it remains truly remarkable.

If you would you care to comment on the numerical 
properties of using Horner vs. Clenshaw for 
series expansions, I shall be most grateful.

I am also especially interested in the relevance 
of using IEEE 10 byte floating point format 
instead of 8 byte double precision, since it is 
said to be the native mode of Intel hardware 
floating point implementations, even though it's 
not available in all compilers.  I have not 
noticed any speed disadvantage when using it, and 
it perhaps provides a bit more precision at low cost.

Irwin Scollar