On Wednesday 08 July 2009, Nikos Alexandris wrote: > There is something strange with the values though (they expand from min > = -32687 max = 32645). Don't have the time to dig further, maybe there > are details in the meta-data about it (!?).
This looks like an overflow problem. Could it be that this file contains unsigned 16 / 32 bit integers, but is being read in as signed 16 bit integers? This used to happen when reading in Arc ASCII grids that contained very large numbers (> 32768) somewhere other than in the first couple of lines. I am pretty sure this bug has been fixed-- but I am not sure how GDAL is interpreting this specific file. It would be useful to use gdal_translate to copy the file, forcing the bit-size of the output to something else. Here was the original GRASS ticket: http://trac.osgeo.org/grass/ticket/166 and the subsequent GDAL ticket: http://trac.osgeo.org/gdal/ticket/2369 There are some tips in the GDAL ticket on forcing a file to be read as a 32bit integers (etc.). Quoth Frank W: Note that with gdal_translate you can convert pixel types on the fly, so if you know the data range is suitable for Int16, you could do "gdal_translate -ot Int16 in.grd out.tif" for instance. Cheers, Dylan -- Dylan Beaudette Soil Resource Laboratory http://casoilresource.lawr.ucdavis.edu/ University of California at Davis 530.754.7341 _______________________________________________ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
