[Gdal-dev] optimum overview settings?

[Frank Warmerdam]

Matt Wilkie wrote:
> Chapman, Martin wrote:
> 
>> Matt,
>>
>> Also, be aware that if you are writing an ovr file, and an ovr file with
>> the same name exists, the gdal lib will append to the file, resulting in
>> a file with more ovr's than you expect.  Moral of the story...delete the
>> other ovr first.   

Martin / Matt,

Martin is right that you have to be wary about existing overviews.  gdaladdo
attempts to add requested overview levels to existing levels or recreate
existing levels if they match requested levels.

> What happens with geotiffs, where the overviews are embedded?

They cannot be easily deleted (like external files) so if you really want
to get rid of them you pretty much have to gdal_translate the file to a new
file which won't have the overviews.

Best regards,
-- 
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