Markus Metz wrote: > Considering this, rather use e.g. raster_min - 1 as default nodata value > for GDAL floating point datatypes?
If fabs(raster_min) is large, raster_min - 1 won't be exactly representable, and may be rounded to raster_min. You would need to subtract a value which depends upon the exponent. Also, the input data may contain -DBL_MAX. For FCELL, if the map is large enough, it's possible that *all* finite values occur in the data. The question is: is GDAL's no-data value allowed to be any FP value, or must it be finite? I'm guessing that the GDAL documentation doesn't say (similarly, I don't think it's documented whether GRASS FCELL/DCELL values are allowed to be infinite). Actually, this may depend upon the format. If a format supports FP, the format's specification may dictate whether or not NaN and/or inifinities are considered valid. -- Glynn Clements <gl...@gclements.plus.com> _______________________________________________ grass-dev mailing list grass-dev@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-dev
