[GRASS-dev] Re: [GRASS GIS] #73: r.out.gdal tiff output does not work

[Dylan Beaudette]

On Wednesday 15 April 2009, Glynn Clements wrote:
> Dylan Beaudette wrote:
> > 3. Allow the user to specify what they would like NULL cells encoded as.
> > Unless I am overlooking something, it would seem reasonable to export a
> > CELL map to a signed integer format, and use some obvious negative value
> > for NULL:
>
> If you're exporting to a 32-bit (signed or unsigned) integer format,
> the obvious choice for null is 0x80000000. That's what GRASS uses
> internally, so it can never occur as a legitimate value (if a
> computation ends up producing that value, it will get treated as a
> null in all regards).

Thanks Glynn. It would be good to know about 'obvious' values for any given 
datatype.

Cheers,
Dylan


-- 
Dylan Beaudette
Soil Resource Laboratory
http://casoilresource.lawr.ucdavis.edu/
University of California at Davis
530.754.7341