[Proj] NADCON spec

[Richard didier]

Hi all,

I need to produce NADCON grid from our NTV2 grid.

I have searched the web for NADCON grids specs and only found that a NADCON 
grid is a bundle including the data AND the software that reads them ... I, 
also, found that there are two files needed (one for longitudes, another one 
for latitudes) and that longitudes/latitudes must be round even values ... 
But, I am not sure of all of that.

On the other hand, PROJ.4 includes a reader for converting lla (ascii) to 
binary ... and lla is mentioned in some web pages.

So, is there "real" specifications for NADCON Grids ? and could someone point 
me to them ?

Sincerely,
-- 
Didier RICHARD, chef du pôle technique Géoportail pour l'IGN
Institut Geographique National           tel: +33/0 1.43.98.83.23
2/4 Avenue Pasteur                       fax: +33/0 1.43.98.80.88
F-94165 St-Mande Cedex                e-mail: Didier.Richard at ign.fr