On Dec 8, 2009, at 6:21 AM, Kor de Jong wrote: > Hi Bart, > > On Tuesday 08 December 2009 12:33:10 bart...@osgis.nl wrote: >> in ArcMap I see negative values, in GDAL all values seem to have a shift >> of 256, so -21 becomes 235. Nodata values are also off with 256, so -256 >> in ArcMap becomes 0 in GDAL. > > The pixel type of your input is char (signed 8 bit). The no-data value > is -256 (which cannot be represented by the signed 8 bit, btw). > > For some reason your data gets converted from a signed 8 bit type to an > unsigned 8 bit type. > > Looking at the trunk version of sderasterband.cpp I see that GDT_BYTE is > taken to be the equivalent of SE_PIXEL_TYPE_8BIT_S. If this means that > an input of signed 8 bit value is stored in an unsigned 8 bit value, > than that would explain what you are seeing. An alternative would be to > update this code to return GDT_Int16, which will leave your data intact. > Line 833.
This is very likely the culprit. Thanks Kor. Please file a bug on this and I will try to apply it before the release. I would note that I don't have SDE anymore to be able to test against, so I would have to depend on Bart's assessment of whether or not the issue is resolved. Howard _______________________________________________ gdal-dev mailing list gdal-dev@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/gdal-dev
