[gdal-dev] HFA_USE_RRD vs USE_RRD

Frank Warmerdam warmerdam at pobox.com
Sat Aug 2 09:20:21 EDT 2008

Maciej Sieczka wrote:
> Hi!
> If I use the followiwng syntax:
>  gdaladdo --config HFA_USE_RRD YES --config USE_RRD YES some.tif 2 4 8
> a small aux file and a big rrd file are created. If I use:
>  gdaladdo --config USE_RRD YES some.tif 2 4 8
> only a big aux is created.
> In the 1st case the sum of aux and rrd file sizes is equal the size of
> the aux file from the 2nd case.
> What is the difference between the 2 methods, is any better (in what
> terms) and could gdaladdo man page please address these issues
> (currently it only mentions USE_RRD alone).


The HFA_USE_RRD was implemented at the request of a client to mimic the
behavior of another application.   It isn't really any better than just
putting the overviews in the .aux file.  If you file a ticket I'll try and
document things somewhat better.

Best regards,
I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | President OSGeo, http://osgeo.org

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