[Gdal-dev] RE: Strange NoData value from a MrSID image (Peng Gao)

[Michael P. Gerlek]

> I have a case where MrSID SDK reports NoData values (0, 0, 0) for
> 3 bands, and I have a MrSID image containing black text with 
> value (0, 13, 14).  Since GDAL uses band specific NoData 
> interpretation, the band 1 is nodata. My app considers a 
> multiband pixel NoData if any of the band is nodata. As the 
> result, the black text is displayed transparent.
> I could ignore
> MrSID NoData color at application level. But I can't handle 
> the case where the NoData values come from PAM.
> 
> One solution could be not using native MrSID NoData color as 
> GDAL band specific NoData value (because it's not), and 
> adding a new call at Dataset level to get NoData color for 
> the entire dataset for apps that want to make use of the NoData color?
> 
> What do you think?

That certainly would be okay - but this is really a question at the
GDAL / MrSID driver level, though.  Frank?

-mpg