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

[Frank Warmerdam]

On 6/23/05, Michael P. Gerlek <mpg at lizardtech.com> wrote:
> Peng Gao wrote:
> 
> > GDAL returns a strange NoData value (-1.2197742815800439e-012)
> > from one of my mrSID images. The image is 8-bit and has 3 bands.
> >
> > MrSIDRasterBand::MrSIDRasterBand( MrSIDDataset *poDS, int nBand )
> > {
> >   ...
> >   dfNoDataValue = poDS->poNDPixel->getSampleValueFloat32( nBand - 1 );
> >   ...
> 
> If this is 8-bit data, then we should be using getSampleValueUint8(),
> not getSampleValueFloat32().
> 
> The "datatype" in those function name refers to the underlying datatype
> of the sample, not the desried return type or such.  I think I even
> documented that :-)

Michael,

Ah!  Thanks, I'll fix that.  This would certainly explain why Peng was
getting junk values. 

... I see Andrey has beat me to it.  Thank goodness for CVS reporting
via IRC. 

Best regards,
-- 
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