[gdal-dev] LZW Compression on geotiffs

[Andrea Aime]

On Thu, Oct 2, 2014 at 9:55 AM, Jukka Rahkonen <jukka.rahkonen at mmmtike.fi>
wrote:

> Rahkonen Jukka (Tike <jukka.rahkonen <at> mmmtike.fi> writes:
>
>
> > > True, a way to improve things might be to specify -co PREDICTOR=2.
> Should
> > > apply to both LZW and DEFLATE.
> > > This is one of the filter that might be used by PNG, except that PNG
> has
> different
> > > filters, so it will eventually beat TIFF deflate.
> >
> > Not a bad suggestion.
> >
> > Original                                             424 MB
> > DEFLATE without predictor          380 MB
> > DEFLATE with -co predictor=2     280 MB
>
>
> One more test with LZW
>
> Without predictor                 474 MB
> With -co predictor=2              307 MB
>
> Is there something that prevents changing the default to "predictor=2" from
> the current default value "1"?
>

Interesting... wondering how much the predictor affects decoding speed
though (it is
a common case to have to compress once, and read many times out of the
compressed file)

Cheers
Andrea

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