[Gdal-dev] does HFA driver decrease performance?

[Matt Wilkie]

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.

thanks,

-- 
matt wilkie
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