[gdal-dev] Passing RAT between drivers, including VRT

[Even Rouault]

Le jeudi 15 août 2013 20:04:51, Ivan Lucena a écrit :
> Hi Even,
> 
> I double checked and I noticed that this is not true:
> > > The RAT is transferred to the geotiff file in both instances.
> 
> I pass -a_nodata and got no RAT as you can see on the
> following log.
> 
> Without -a_nodata the file gtiff_i8u_c_i.tif.aux.xml is create with the
> full RAT.

Yes, that's exactly what I said in my previous email.

> 
> But for output HFA that is still true. I can pass
>  -a_nodata or not and the RAT is always copied to the output.
> 
> Try that:
> 
> $ gdal_translate -of hfa i8u_c_i.img hfa_i8u_c_i.img -a_nodata 0
> $ gdal_translate -of hfa i8u_c_i.img hfa_i8u_c_i.img
> 
> Is that the same that you are getting over there?

Well, this is different. The HFA driver is a bit particular in its behaviour 
and reports a RAT when there's a color table (in fact a color table is a 
particular type of RAT). So technically the RAT of the source IMG is not 
transferred into the target IMG in the -a_nodata 0 case, but the color table 
is.


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