[GRASS5] r.in.gdal updates?
glynn.clements at virgin.net
Fri Feb 28 16:13:54 EST 2003
Markus Neteler 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):
> - 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.
Once that's been determined, generating the colour table is trivial.
NB: this is why d.rgb, r.composite etc need the grey-scale colour
tables; so that they can translate a cell value to an intensity.
Glynn Clements <glynn.clements at virgin.net>
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