[Proj] Unknown projection?

[Gerald I. Evenden]

On Saturday 13 September 2008 11:42:29 am support.mn at elisanet.fi wrote:
> "Gerald I. Evenden" <geraldi.evenden at gmail.com> kirjoitti:
> > On Saturday 13 September 2008 10:59:24 am Paul B. Anderson wrote:
> > > - Janne,
> > >
> > > Your map graphic appears to be in the Winkel Tripel map projection. I
> > > would also suggest that it is using Oswald Winkel's original selection
> > > of 50.46667 degrees as the Special Parallel.
> > >
> > > Note that by the 1950s John Bartholomew was using a special parallel of
> > > 40 degrees for his version of the Tripel, giving his graphic a more
> > > flattened appearance in the Y direction.
> >
> > This is exactly why I include the projection math in the manual.  The
> > factor Anderson is discussing is +lat_1 option for the +proj=wintri
> > projection. Select your own option value and name a new projection.  ;-)
>
> Ok, now the problem seems to be that "wintri" does not have any inverse
> projection available. What is the reason not to have inverse projections
> for all routines in the library... math is too hard?
>
> Janne.

Sometimes yes; sometimes no; sometimes lack of interest.  The are several of 
the projections in this azimuthal category that do not have inverses and, 
based upon a quick look, are probably solvable.

Do you know for sure that the projection you showed is Winkel Tripel?  You do 
not need an inverse to determine this.

-- 
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