[Proj] Why?

[Gerald I. Evenden]

One burning question has come up in my mind about the need for inverse 
solutions for non-grid-system projections like Aitoff, Hammer, etc.: why?

It is easy to understand the need in cadastral work to be able to freely 
interchange between Cartesian and Geographical space because the source of 
information is in either system.

But Aitoff or Winkel Tripel.  What source information is in either projection.  
Are people now going to digitize NGS maps?  Certainly nobody uses Winkel 
Tripel for cadastral application---do they?

Just very curious.

-- 
The whole religious complexion of the modern world is due
to the absence from Jerusalem of a lunatic asylum.
-- Havelock Ellis (1859-1939) British psychologist