[Qgis-developer] Projection parameters for french NTF

[Laurent C.]

Hello,

It seem that the projections parameters for the french lcc projection are wrong.
Today, all the epsg's 275xx have the following parameter :
+lon_0=-2.33722917

With the current parameters, when I import some gps points(lat-lon)
and reproj them to french's Lambert zone II, the points are shifted by
hundreds of kilometers to the east.

Maybe the param should be :
+lon_0=2.33722917
or maybe :
+lon_0=0, because +pm=paris
Well, I don't know exactly.

Here are my grass PROJ_INFO file (which is working) :
name: Lambert Conformal Conic
proj: lcc
ellps: clark80IGN
a: 6378249.2000000002
es: 0.0068034876
f: 293.4660212940
lat_0: 46.8000000000
lat_1: 45.8989188889
lat_2: 47.6960144444
lon_0: 2.3372291667
x_0: 600000.0000000000
y_0: 2200000.0000000000

Maybe is it a proj.4 problem. Here is the epsg file from proj 4.4.9 :
<27572> +proj=lcc +lat_1=46.8 +lat_0=46.8 +lon_0=-2.33722917
+k_0=0.99987742 +x_0=600000 +y_0=2200000 +a=6378249.2 +b=6356515
+towgs84=-168,-60,320,0,0,0,0 +pm=paris +units=m +no_defs  <>

The epsg file from proj 4.5.0b2 :
<27572> +proj=lcc +lat_1=46.8 +lat_0=46.8 +lon_0=0 +k_0=0.99987742
+x_0=600000 +y_0=2200000 +a=6378249.2 +b=6356515
+towgs84=-168,-60,320,0,0,0,0 +pm=paris +units=m +no_defs  <>

The proj esri file :
<27572> +proj=lcc +lat_1=46.8 +lat_0=46.8 +lon_0=2.33722917
+k_0=0.99987742 +x_0=600000 +y_0=2200000 +a=6378249.2 +b=6356515
+towgs84=-168,-60,320,0,0,0,0 +pm=paris +units=m +no_defs  no_defs <>

I'm not a gis guru, and I don't know exactly what to think. It could
be great if some French users could give a clue.

Thanks,

Laurent