[OSRS-PROJ] epsg code for swiss grid and NTF Lambert IGN

Frank Warmerdam warmerdam at pobox.com
Thu Sep 20 17:05:28 EDT 2001

Claude Philipona wrote:
> I don't know if it might insterest somebody or if it could be implemented in the
> next release of proj, but here are the epsg code for Swiss grid (used with swiss
> topo map) and NTF Lambert IGN (used with IGN france topo map).
> I have tested all these configuration with reference points, and the result are
> correct, with a small error below one meter for projection transform
> (datum-shift) between swiss and france
> Claude Philipona
> # CH 1903 / Swiss Oblique Cylindrical
> <9814> +proj=somerc +lat_0=46d57'08.66"N +lon_0=7d26'22.50"E +ellps=bessel
> +x_0=600000 +y_0=200000 +towgs84=674.374,15.056,405.346 +units=m +k_0=1 +no_defs
> <>
> # NTF (Paris) / France I
> <27581> +proj=lcc +a=6378249.2 +b=6356515.0 +lat_0=49d30'0.0"N
> +lon_0=2d20'14.025"E +lat_1=48d35'54.682"N +lat_2=50d23'45.282"N +x_0=600000.0
> +y_0=200000.0 +towgs84=-168,-60,+320 +units=m no_defs <>
> # NTF (Paris) / France II
> <27582> +proj=lcc +a=6378249.2 +b=6356515.0 +lat_0=46d48'0.0"N
> +lon_0=2d20'14.025"E +lat_1=45d53'56.108"N +lat_2=47d41'45.652"N +x_0=600000.0


These aren't the same projection definitions as found in the EPSG tables
(at least the EPSG 4.3 tables) which is an LCC 1SP projection with a scaling
factor.  How did you derive your projections, and are they equivelent to
the EPSG projections?  I am hesitant to incorporate them into the EPSG file
without greater confidence about their relationship to the EPSG definition.

Best regards,

I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | Geospatial Programmer for Rent

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