[Gdal-dev] Reproject with Mapserver vs gdalwarp

[José Vicente Higón]

On Wednesday 25 July 2007 15:27:45 Frank Warmerdam wrote:
> José Vicente Higón wrote:
> > In both cases I was using the latest FWTools release (1.3.4)
> >
> > Why Did I get differents results in MApserver and gdalwarp?Any clue?
>
> José,
>
> GDAL does not generally use the PROJ.4 epsg init file.  Instead it has
> a set of .csv files with the EPSG definition information.
>
> I think you will want to edit this line of FWTools/data/pcs.csv:
>
> 23030,"ED50 / UTM zone
> 30N",9001,4230,16030,9807,1,0,8805,0.9996,9201,8802,-3,9102,8801,0,9102,880
>7,0,9001,8806,500000,9001,,,,,,
>
> To include include the TOWGS84 values.  Something like:
>
> 23030,"ED50 / UTM zone
> 30N",9001,4230,16030,9807,1,0,8805,0.9996,9201,8802,-3,9102,8801,0,9102,880
>7,0,9001,8806,500000,9001,-87,-98,-121,0,0,0,0
>
>
> You might want to verify that GDAL is picking up the definition properly
> by entering "testepsg EPSG:23030" in the FWTools shell which will
> report the coordinate system in various forms.  Make sure that one (the
> first I think) includes the proper TOWGS84[] parameters and that they make
> it into the final PROJ.4 rendering.
>
> Best regards,

Thank you for your answer,
I've installed gdal 1.4.0 and I've changed the file 
gdal-1.4.0/share/gdal/pcs.csv, now I have a line like this:
23030,"ED50 / UTM zone 
30N",9001,4230,16030,9807,1,0,8801,0,9102,8802,-3,9102,8805,0.9996,9201,8806,500000,9001,8807,0,9001,-87,-98,-121,0,0,0,0
However, I am still getting a wrong reprojected image (shifted over a hundred 
meters).  I think the reason is because I am not specifying the nad grid 
shift file ( in my case sped2et.gsb). Am I right?
How can you specify to gdal for using this kind of file in reprojections?

Thanks in advance