[Proj] Some need for updated proj-4 manuals

[Hamish]

> Our application's manuals tell what projections and datums are. What is
> needed is "how to use them", "how does a change of some parameter
> affect the projection", "what are the exact names of those parameters",
> "which way towgs84 numbers should be given", "what projections are
> used and how in different parts of the earth", etc.

Janne, 

with due respect, libproj's documentation responsibility ends with the library interface and internals. It is well beyond the scope of the
project to supply a linking application's end-users with a textbook
primer on geodesy. I view it as a bit ungrateful to ask them to do so
for you, regardless of the fact that they may be experts in the field
and well qualified to do so.

"What do PROJ4's +a, +lon_0, and +k terms mean? Which convention are
the 7-term towgs84 terms given in?" would be valid subjects of PROJ4
documentation.

"What projections are used and how in different parts of the earth" is
far far beyond the scope.


Having said that, I am sure the members of this list could collectively
build an excellent "For Further Reading" list. We maintain a small list
of links to useful guides in the GRASS GIS Wiki:
  http://grass.osgeo.org/wiki/Gis_Concepts#Geodesy_and_Cartography
   (direct improvements to that wiki page are most welcome)


regards,
Hamish