[GRASS5] r.in.gdal updates?
neteler at itc.it
Mon Mar 10 09:46:14 EST 2003
On Sun, Mar 02, 2003 at 06:53:56PM +0000, Glynn Clements wrote:
> Glynn Clements wrote:
> > > I would like to ask if a developer is willing to update r.in.gdal
> > > (Frank Warmerdam told me that he won't do that at time):
> > >
> > > Outstanding
> > > - fix the grey color tables issue for RGB maps
> > The main problem here is determining the overall range of the data,
> > i.e. which values correspond to black and white. Black is almost
> > certain to be 0, but determining white is more difficult. Usually it's
> > ((1<<bit_depth)-1), but you need to know what bit_depth is.
> The upshot of a private conversation with Frank is that GDAL doesn't
> make this information available. Consequently, you would need to use
> heuristics to determine the bit depth (and hope that the image isn't
> too dark).
We may start to implement it only for RGB images at time. Usually
they should be 8 bit. GDAL cannot deliver the bit depth of the
read format (maybe GetRasterDataType())?
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