Hello, I'm trying to add a line in the PostGIS SPATIAL_REF_SYS Table. My SRS WKT is: PROJCS["NTF_Lambert_II_étendu",     GEOGCS["GCS_NTF",         DATUM["Nouvelle_Triangulation_Francaise",

<br>            SPHEROID["Clarke_1880_IGN",6378249.2,293.46602]],<br>        PRIMEM["Greenwich",0.0],<br>        UNIT["Degree",0.0174532925199433]],<br>    PROJECTION["Lambert_Conformal_Conic_1SP"],

<br>    PARAMETER["False_Easting",600000.0],<br>    PARAMETER["False_Northing",2200000.0],<br>    PARAMETER["Central_Meridian",2.3372291667],<br>    PARAMETER["Standard_Parallel_1",

45.8989188889],<br>    PARAMETER["Standard_Parallel_2",47.6960144444],<br>    PARAMETER["Scale_Factor",1.0],<br>    PARAMETER["Latitude_Of_Origin",46.8],<br>    UNIT["Meter",1.0]]<br>

<br>And I'm trying to figure out what is the corresponding proj4text:<br>+proj=lcc    +x_0=600000<br>                  +y_0=2200000<br>                  +lon_0=2.3372291667<br>                  +lat_1=45.8989188889<br>                  +lat_2=

47.6960144444 <br>                  +k_0=1<br>                  +lat_0=46.8<br>                  +units=m<br>                  +a=6378249.2<br>                  +towgs84=-168,-60,320,0,0,0,0<br>                  +pm=greenwich

<br><br>However, I've some problems finding information about projections arguments, especially about spheroid information. <br><br>SPHEROID["Clarke_1880_IGN",6378249.2,293.46602]],<br><br>I guess I can use "+a" for 

6378249.2 but what is  the argument for  293.46602 ? NB: I already tryied : $ proj -le | grep clrk80    clrk80 a=6378249.145    rf=293.4663      Clarke 1880 mod. But it seam that I can't use the +ellps=clrk80 because the values don't match exactly with mine.

<br><br>May I use +rf=293.46602 ?<br><br>What about this UNIT["Degree",0.0174532925199433]], ?<br><br><br><br>Thanks in advance<br><br><br clear="all">Best regards<br>-- <br>Romain CHERCHI