Matthieu Rigal wrote:
Hi folks,
Currently running GDAL 1.7.1, I noticed a regression towards the 1.6.x branch
which I could not find in the tickets.
Teh GetDescription() always seems to return empty strings, except for just
created file and just setted description...
Here is a description of the bug, I don't think it is quite the expected
result :
from osgeo import gdal
xT = gdal.GetDriverByName('GTiff').Create('test-desc.tif',10,10,1)
xB = xT.GetRasterBand(1)
xB.SetDescription('test')
xT = None
xT2 = gdal.Open('test-desc.tif')
xT2.GetRasterBand(1).GetDescription()
''
The 1.6.1 returns:
'test'
Is it a known bug ? Solved in further versions ?
Matthieu,
I confirmed the problem but was unable to reproduce correction operation
against the current 1.6 branch so whatever changed appears to have changed
there as well.
I presume with 1.6.1 you are seeing a .aux.xml file created - is that right?
There is no special handling of the raster band description in the geotiff
driver itself, so saving it falls to the GDALPamRasterBand. I see it also
has no override for SetDescription() so it falls to GDALMajorObject to
hold the description. In GDALPamRasterBand::SerializeToXML() a non-empty
description will be saved to the .aux.xml file; however, SerializeToXML()
is not called unless there is some record of the PAM information being dirty.
Since SetDescription() was not overridded in GDALPamRasterBand there was
no mechanism to set GPF_DIRTY in the pam layer.
Without more investigation I can't see why things regressed after 1.6.1.
I suspect it was a case of other information being handled a different
way so less gets written to the .aux.xml file.
I believe the fix is to override SetDescription() in GDALPamRasterBand
and to set the dirty flag there.
I'd appreciate it if you could file a ticket, and copy in the above
discussion.
Best regards,
--
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