[postgis-users] Buggy transform() function in 1.0RC1 ?

[strk at refractions.net]

Nicolas, I'm trying to figure out what to do with these *bogus* entries
in spatial_ref_sys.
The problem is that there are more then a single entries for Paris,
so I think all of them are bogus.
Another problem is: "would a newer PROJ4 version correclty interpret the
new paramaters?".
What PROJ4 version are you using ? Could you check if newer PROJ4 give
a different result ?
--strk;

On Wed, Feb 02, 2005 at 06:50:46PM +0100, RIBOT, Nicolas wrote:
> Transform() is not buggy.
> 
> To follow my previous post, and thanks to Michael Michaud that noticed the
> differences, the spatial_ref_sys.sql provided with postgis 1.0 RC is not the
> same as the one provided with the previous Postgis versions, at least for
> french projections.
> Namely, for SRID=27582, the proj4 parameters in postgis 0.8:
> 
> +proj=lcc
> +lat_1=46.8
> +lat_0=46.8
> +lon_0=2.337229166666667
> +k_0=0.99987742
> +x_0=600000
> +y_0=2200000
> +a=6378249.2
> +b=6356514.999904194
> +pm=2.337229166666667
> +units=m
> 
> and in postgis 1.0RC:
> 
> +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 sign of the longitude of origin is not the same, the value of the prime
> meridian is also different.
> 
> Can we fear other projection systems to be inaccurate ?
> Why the values of these well-know systems have changed between versions ?
> 
> Thanx
> Nicolas Ribot
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