[GRASSLIST:7483] Projection LAMBERT III (South of France) parameters

GRASS GRASS user
1

Hello,

For starters I use mapserver but my problem is not with Mapserver itself but with the projection parameters which must be the same in Grass.

I can't find the right PROJECTION object's parameters in my .map file for
coords in LAMBERT III (used for the South of France).

Though, when I translate these coords into the WGS 84 system (epsg:4326),
it works fine.

Maybe the coords in the epsg file are wrong.

I used the following parameters and none of them worked :

"proj=lcc"
"lat_1=44.10000000000001"
"lat_0=44.10000000000001"
"lon_0=2.33722917"
"k_0=0.999877499"
"x_0=600000"
"y_0=200000"
"a=6378249.2"
"b=635651"
"pm=paris"
"units=m"

"proj=lcc"
"lat_1=44.10000000000001"
"lat_0=44.10000000000001"
"lon_0=2.33722917"
"k_0=0.999877499"
"x_0=600000"
"y_0=3200000"
"a=6378249.2"
"b=6356515"
"pm=paris"
"units=m"

"proj=lcc"
"lat_1=44.10000000000001"
"lat_0=44.10000000000001"
"lon_0=2.33722917"
"k_0=0.999877499"
"x_0=600000"
"y_0=3200000"
"a=6378249.2"
"b=6356515"
"pm=paris"
"units=m"

"proj=lcc"
"lat_1=44.10000000000001"
"lat_0=44.10000000000001"
"lon_0=2.33722917"
"k_0=0.999877499"
"x_0=600000"
"y_0=200000"
"a=6378249.2"
"b=6356515"
"pm=paris"
"units=m"

"init=epsg:27563"
"init=epsg:27573"
"init=epsg:27583"
"init=epsg:27593"

Did anyone ever run an project that worked with LAMBERT III coords ?

thanks

regards

2

Le jeudi 07 juillet 2005 à 07:05 +0000, Selim HERNANDEZ a écrit :

Did anyone ever run an project that worked with LAMBERT III coords ?

thanks

I ran with some problems using esg:27572 (Lambert II) for the South of
France. Points were some hundred kilometers on the right of their real
situation when projected from espg:4326 to epsg:27572.

I had to correct the epsg file. Here are the original and corrected
parameters :

# NTF (Paris) / Lambert zone II
# BAD ORIGINAL
# <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 <>
# WORKING AND VERIFIED
<27572> +proj=lcc +a=6378249.2000000002 +b=6356515.000 +es=0.0068034876
+rf=293.4660212940 +lat_0=46.800N +lon_0=2d20'14.025E
+lat_1=45d53'56.108N +lat_2=47d41'45.652N +x_0=600000.000
+y_0=2200000.000 +units=m +no_defs +towgs84=-168,-60,+320

Hope this helps.

Didrik