[gdal-dev] BigTIFF Overviews ( OVR files )

[Christopher Schmidt]

On Tue, Feb 09, 2010 at 01:57:26PM -0800, David Fogel wrote:
> Hi:
> 
> In the process of moving data into GeoTIFF, I am re-creating pyramids
> (OVR files).  The good news: It takes fewer than ten minutes to create
> an LZW Horizontal Differenced compressed 3.5 GB file on a Windows 7
> box using GDAL 1.70+ ( via Tamas Szekeres site; 64-bit precompiled ).
> 
> The OVR files are problematic.  Using gdal_translate, I can resize by
> 50% in less than ten minutes.  Using gdaladdo, the first layer ( "2" )
> takes hours to complete.
> 
> This is for SRTM 16-bit data.  It appears that something is amiss.
> 
> Tips and tricks?

One piece of advice; I find that adding overlays is often significantly
helped by increasing the GDAL_CACHEMAX setting.

gdaladdo --config GDAL_CACHEMAX 800 file.tif 2 4 8 16 32 64

800 is MB of memory; as a result, it probably makes sense to limit this
if your platform is low on free RAM.

Regards,
-- 
Christopher Schmidt
MetaCarta