[gdal-dev] Erdas .img format (HFA) overview troubles
even.rouault at mines-paris.org
Mon Jun 1 12:09:49 EDT 2009
I see this in hfadataset.cpp :
CPLErr HFADataset::IBuildOverviews( const char *pszResampling,
int nOverviews, int *panOverviewList,
int nListBands, int *panBandList,
void * pProgressData )
if( GetAccess() == GA_ReadOnly )
return GDALDataset::IBuildOverviews( pszResampling,
pfnProgress, pProgressData );
So with gdaladdo -ro, it defaults to GDALDataset::IBuildOverviews(), that will
fail because the default overview mechanism isn't initialized as Frank noted
What you want to use is the HFA_USE_RRD global config option (documented after
the list of creation options)
gdaladdo --config HFA_USE_RRD YES test.img 2 4 8
Le Monday 01 June 2009 17:52:43 Frank Warmerdam, vous avez écrit :
> Christiaan Janssen wrote:
> > On the page http://www.gdal.org/frmt_hfa.html, it mentions the creation
> > of .ovr files under the Creation Issue section.
> I have removed this inaccurate comment.
> > Also, am I wrong in thinking
> > the command "gdaladdo -ro test.img 2 4 8" should have at least generated
> > an .aux (or .rrd) file and not errored the way it did? Thanks.
> The error message was unhelpful, but I presume the issue is that overviews
> cannot be generated in a read-only file. If you would like to file a
> ticket on this, I could look into more appropriate error handling.
> I would add, if you wanted ovr support it should be relatively trivial for
> you to add it in your local build with a call to initialize the
> overview manager at the end of the Open() method.
> poDS->oOvManager.Initialize( poDS, poOpenInfo->pszFilename );
> I am hesitant to do this in the mainline code though.
> Best regards,
More information about the gdal-dev