[Proj] Spheroidal gnomonic projection

[Karney, Charles]

> From: Charles Karney [ckarney at sarnoff.com]
> Sent: Tuesday, June 01, 2010 13:42
>
> ...
> The method of constructing the projection entails defining
> ...
>   * M, the geodesic scale.  Take two geodesics of length s which are
>     parallel close to the center and initially separated by dt.  The
>     endpoints are separated by M * dt.
> 
> ... The geodesic scale was introduced (I think) by G. V. Bagratuni,
> ...
> Questions:
> ...
> (2) Is Bagratuni this first person to define M?

No, that would be Gauss (of course!).  He uses the symbol n (which
Bagratuni adopts).  See

  http://books.google.com/books?id=a1wTJR3kHwUC&pg=PA35