[Gdal-dev] Re: single ECW output from multiple input tiles

[Tom Lynch]

Hi Ken,

Your input statistics work out to a ~0.4 TB total input dataset. 
There's nothing intrinsic to the ECW compression libraries that
prevents a dataset of this size from being compressed.  For example,
ER Mapper 7.0, which is based on similar technology, is often used to
compress ECW mosaics from multi-TB input datasets on machines
comparable to yours.

We (ER Mapper) haven't tested gdal_translate with input datasets of
this size.  It's possible that there's some overhead introduced to
processing that prevents them from being successfully compressed for
the moment.  You could also be seeing a difficult to manifest bug in
GDAL, e.g. a minor resource leak that is not usually apparent.

On 5/24/05, Ken Boss <Ken.Boss at dnr.state.mn.us> wrote:
> Hello Frank--
> 
> I tried again to use gdal_translate to create a large ECW output from
> input tiles described in a .vrt file, this time with a more appropriate
> pagefile config.  But again it failed after ~30 hours at 80% completion
> owing to a memory allocation error.  Here are the basics of my setup:
> 
> Win2k
> single 2.4 Ghz Pentium 4 processor
> 1.5 GB RAM
> 2.5 GB pagefile space
> ~600 input tiles in .vrt
> typical tile size 400 MB
> output image 307060 x 464371 pixels x 3 bands (lots of offsite)

-- 
Tom Lynch
Development, ER Mapper
Phone:      +61 8 93882900
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Email:      tom.lynch at ermapper.com
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