[GRASS-user] GRASS export GeoTiff adventure... continued :-)
nikos.alexandris at felis.uni-freiburg.de
Sun Aug 3 17:54:52 EDT 2008
On Sun, 2008-08-03 at 19:32 +0100, Glynn Clements wrote:
> Nikos Alexandris wrote:
> If you import data which doesn't contain any nulls, then re-export it,
> the nodata= option will typically have no effect, as there aren't any
> nulls which need to be converted.
> OTOH, if the GRASS raster which you are exporting contains values from
> 0 to 255 inclusive, and also contains nulls, that's 257 possible
> values. If the format to which you are exporting only has 256 possible
> values (i.e. 0 to 255), then you can't avoid losing information.
Thank you Glynn. It just got stuck to my mind that nodata= will convert
the 255 values in nodata and not the opposite. So I though that my 255's
will go away :-)
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