[GRASS5] French projections

[Michel Wurtz]

Speaking about updating projection definitions, I have noticed that
lcc (Lambert Conformal conic) doesn't have false easting or northing
(at least when using g.setproj).  On the other hand, France will now
use a new system (Lambert 93) based on GRS80 ellispoid, instead of
the old one (a familly of lcc projections) based on Clarke 1880
ellipsoid (IGN modified).  This has lead to a conversion grid for
precise transformation (something like NAD27/NAD83).
Since proj has the ability to use such a grid, it sounds relatively
easy to incorporate french geodetic systems.  All the détails
parameters, formulas and algorithms can be found (in french :-) at

http://www.ign.fr/fr/PI/activites/geodesie/rgf93/OUTILS/index.html

--
Michel WURTZ - DIG - Maison de la télédétection
               500, rue J.F. Breton
               34093 MONTPELLIER Cedex 5