[mapserver-users] gdaladdo help

[Frank Warmerdam]

Twan Kogels wrote:

> Hello All,
> 
> I have compiled gdal with the gdaladdo utility. With this utility you 
> can create overviews for raster maps. But there is one problem, there is 
> no documentation for gdaladdo. The "raster howto" does not yet include a 
> example of using the gdaladdo ulility, also no documentation can be 
> found online.
> 
> Can anybody give me a hint on how to use the gdaladdo utility?


warmerda at gdal[430]% gdaladdo
Usage: gdaladdo [-r {nearest,average,average_mp,average_magphase,mode}]
                filename levels

Example:
 % gdaladdo -r average abc.tif 2 4 8 16


Generally speaking, you would pass the filename to build overviews for, and
then a list of levels.  Usually the default resampling algorithm (nearest
neighbour resampling) is fine.  Most GDAL supported formats support overviews,
though they are usually stored via an external TIFF file with the extension
.ovr that is automatically detected by GDAL.  TIFF files are an exception
where the overviews are actually handled internally.

I have added a note about gdaladdo in the Wiki!

Best regards,

-- 
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
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