r.out.gdal type= and no-data issues

[sieczka]

If data 'type' is not specified and the input raster has nulls, r.out.gdal picks a correct datatype automatically, but sets a bogus no-data value. Example, in spearfish60:

r.out.gdal in=geology out=gelogy.tif
Exporting to GDAL data type: Byte
 100%
WARNING: Input raster map constains cells with NULL-value (no-data). For
         no-data values was used value -2147483648. You can specify nodata
         value by nodata parameter.
r.out.gdal complete.

Note the bogus -2147483648 no-data value, not in Byte datatype range.

If the user specifies 'type=Byte' explicitely, r.out.gdal sets nodata to 255 by default (OK):

GRASS 6.3.svn (spearfish60):~ > r.out.gdal in=geology out=gelogy2.tif type=Byte
Exporting to GDAL data type: Byte
 100%
WARNING: Input raster map constains cells with NULL-value (no-data). For
         no-data values was used value 255. You can specify nodata value by
         nodata parameter.
r.out.gdal complete.

[martinl]

The attached patch should fix this issue.

[martinl]

Please test the attached patch. Martin

[neteler]

I darkly remember that GDAL uses out-of-range values for no data. Possible?

See also

​http://lists.osgeo.org/pipermail/grass-dev/2007-May/031316.html

​http://lists.osgeo.org/pipermail/grass-dev/2007-May/031715.html

Markus

[martinl]

Replying to neteler:

I darkly remember that GDAL uses out-of-range values for no data. Possible?

See also

​http://lists.osgeo.org/pipermail/grass-dev/2007-May/031316.html

​http://lists.osgeo.org/pipermail/grass-dev/2007-May/031715.html

this should be already fixed, see r29555.

Martin

[martinl]

Replying to martinl:

Please test the attached patch. Martin

Patch applied in trunk, r30433. Martin