[Gdal-dev] Reproject with Mapserver vs gdalwarp

José Vicente Higón josevicente.higon at gmail.com
Fri Jul 27 02:46:24 EDT 2007


Thanks a lot for your answer.
I've changed the epsg.wkt and I've dropped the EPSG:23030 entry in pcs.csv  
and now It reprojects perfectly.

> José,
>
> I'm sorry, I missed your specification of a nadgrids file. Generally it is
> bad to specify a +towgs84 parameter and a nadgrid as it isn't absolutely
> certain which will be used.
>
> Unfortunately there is no way to update the pcs.csv file to specify a
> nadgrid.  One thing that might work is to remove the above 23030 line
> from pcs.csv, and add the following line at the beginning of
> gdal/data/epsg.wkt (make sure this is just one line, not split on
> spaces as it likely is in my email):
>
> 23030,PROJCS["UTM Zone 30, Northern Hemisphere",GEOGCS["International 1909
> (Hayford)",DATUM["unknown",SPHEROID["intl",6378388,297]],PRIMEM["Greenwich"
>,0],UNIT["degree",0.0174532925199433]],PROJECTION["Transverse_Mercator"],PAR
>AMETER["latitude_of_origin",0],PARAMETER["central_meridian",-3],PARAMETER["s
>cale_factor",0.9996],PARAMETER["false_easting",500000],PARAMETER["false_nort
>hing",0],UNIT["Meter",1],EXTENSION["PROJ4","+proj=utm +zone=30 +ellps=intl
> +units=m +nadgrids=sped2et.gsb +wktext +no_defs"]]
>
> The "trick" is the EXTENSION["PROJ4","..."] block that tells GDAL/OGR to
> use a particular PROJ.4 translation when converting to proj.4 format.
>
> The epsg.wkt file is, I think, consulted if a pcs is not found in the
> pcs.csv file so it is important that it be properly removed from there for
> this to work.
>
> Best regards,




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