[Gdal-dev] does HFA driver decrease performance?

[Frank Warmerdam]

Matt Wilkie wrote:
> Hello GDAL,
> 
> I recently tried to use gdalwarp to mosaick a bunch of CDED 16 bit 
> rasters into a larger tiff and smacked headlong into the 4gb file size 
> limit. I read somewhere that the HFA driver could be used instead, 
> however when I try that performance goes through the floor. In my first 
> attempt using gtiff it took about 3 hours to reach the 4gb mark. In my 
> second attempt using hfa after 23 hours the output mosaick is only 445mb 
> and only 2/3rd of the input files have been processed (204 of 304).
> 
> Any idea what's going on?
> 
> My command lines used are:
> 
> # First attempt with GTIFF
> gdalwarp --optfile %workRoot%\gdalwarp.opt *.dem %dstDir%\dem_115.img
> 
> # Second attempt with HFA
> gdalwarp --optfile %workRoot%\gdalwarp.opt -of HFA *.dem 
> %dstDir%\dem_115.img
> 
> 
> gdalwarp.opt:
>     -srcnodata -32767 -dstnodata -32767 -t_srs nad83
>     -co compress=lzw -wm 1500 -rc -multi
>     -wo skip_nosource=yes
> 
> 
> The source rasters are 304 CDED 1:50,000 tiles for the NTS 115 series 
> available from geobase.ca.

Matt,

I think there is a problem with the HFA driver doing flushes to disk alot
and that this really hammers performance on windows in some circumstances.
Could you boil this down to a somewhat minimal demonstration and file it as
a bug?

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