[Gdal-dev] GDAL LZW PREDICTOR : urgent help

Andrey Kiselev dron at ak4719.spb.edu
Sun Feb 4 06:50:52 EST 2007


On Sat, Feb 03, 2007 at 08:44:39AM +0530, SriRam Prasad Bhasker wrote:
> My Objective is to compress an Image further more .
> 
> Adobe CS2 is compressing the image even further. can anyone what 
> compression algorithm does Adobe Cs2 use to
> compress the TIFF Files... (Is it LZW or LZW predictor)

You can check it yourself using the tiffinfo utility.  Predictor value
will be reported along with compression scheme used for that file.

> right now i am using the below syntax.
> gdal_translate -of GTiff -co PREDICTOR=2 -co compress=lzw ab.tif gplzw.tif

Preictor 2 is used for floating point images only, so if your image is
not floating point you will not get any effect from that predictor. For
integer data choose predictor 1.

Best regards,
Andrey

-- 
Andrey V. Kiselev
ICQ# 26871517



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