[postgis-users] cs2cs parameters

[Jens Schwarz]

Hello,

I'm trying to tell postgis about gk31, EPSG:31255.
I already got help from the proj4 mailing list to get the right parameters, see:
http://lists.maptools.org/pipermail/proj/2007-April/002892.html
and
http://lists.maptools.org/pipermail/proj/2007-April/002899.html

This works for me:

cs2cs +proj=latlong +datum=WGS84 +to +proj=tmerc +ellps=bessel \
    +lat_0=0 +lon_0=13.333333 +k=1.000000 +x_0=0 +y_0=-5000000 \
    +towgs84=577.326,90.129,463.919,5.1366,1.4742,5.2970,2.4232 -r
47.487218 12.254853
-81220.59       261502.07 -47.76

I didn't try to just put these cs2cs parameters to the proj4text column
of a new entry to spatial_ref_sys.

Does any body know about existing, ready to use spatial_ref_sys entries for gk31
I could import to my postgis db?

If I had to create it myself, how would postgis decide to use "cs2cs" or "proj"?

In postgis source I only found pj_transform of lw_geom.
There is a comment that it does no datum shifts...

Thanks for your help.

Jens