[gdal-dev] Re: referencing scanned paper maps

[Jukka Rahkonen]

Oliver Eichler <oliver.eichler <at> gmx.de> writes:


> Now I would like to add this information to the resulting GeoTiff. That's
where my trouble starts. If I add
> +towgs84 to the projection string of the GCPs it seems to get purged by
gdal_translate. Same if I add
> +wktext. And gdalwarp seems to ignore -t_srs parameter. 
> 
> Thus my question: How do I add the +towgs84 parameter to the file, to get it
later on for WGS84 <-> ED50 conversion?

I wonder what might happen if you first add the GCPs only and don't tell
anything about the projection at this phase, and then run gdalwarp with complete 
pjojections strings, somehow like
 gdalwarp -s_srs "+proj=..." -t_srs "+proj=..."

-Jukka Rahkonen-