[gdal-dev] LZW Compression on geotiffs

[Newcomb, Doug]

Well,
I went back and compiled with 1.11.1 with the external geotiff library and
got the same result for LZW, tiling made no difference in size .

As an interesting sideline, I noticed that I had not been compiling with
LZMA compression  previously and compiled gdal 1.11.1 with LZMA.  I ran:


gdal_translate -of “GTIFF” -co “COMPRESS=LZMA” on the original file and got
a file of  149MB in size.

 I noticed that LZMA compression is not listed as one of the compression
options for the GeoTIFF format in the online documentation.  Has that
capability been available long?

Doug

On Wed, Oct 1, 2014 at 9:45 AM, Even Rouault <even.rouault at spatialys.com>
wrote:

> Le mercredi 01 octobre 2014 15:41:06, Newcomb, Doug a écrit :
> > Hi,
> > I have a 4 band uncompressed geotiff ( NAIP data for North Carolina, USA)
> > that is 193 MB
> > I've been going over the compression options for gdal_translate  geotiffs
> > and I note the following:
> > gdal_translate -of “GTIFF” -co “COMPRESS=PACKBITS” gives me a file that
> is
> > 194MB in size
> > gdal_translate -of “GTIFF” -co “COMPRESS=LZW” gives me a file that is
> 232MB
> > in size
> > gdal_translate -of “GTIFF” -co “COMPRESS=DEFLATE” gives me a file that is
> > 177MB in size
> >
> > Of the above  Lossless compression options for geotiff, it seems that
> > DEFLATE is the only one actually compressing.
> >
> > I'm running gdal 1.11.0 on Ubuntu 12.04.3 64 bit compiled with
> ./configure
> > --with-libz   --with-png  --with-libtiff=internal
> >  --with-geotiff=internal   --with-jpeg=internal   --with-openjpeg
> > --with-pg=/usr/local/pgsql/bin/pg_config --with-ogr --with-xerces
> > --with-geos --with-hdf4 --with-hdf5 --with-poppler=/usr/local/lib
> > --with-podofo --with-spatialite --with-netcdf
> >
> > Is this expected behavior?
>
> Doug,
>
> Not completely surprising that lossless methods don't work well with
> aerial/satellite imagery.
> You may also want to test with -co TILED=YES .
>
> Even
>
> --
> Spatialys - Geospatial professional services
> http://www.spatialys.com
>



-- 
Doug Newcomb
USFWS
Raleigh, NC
919-856-4520 ext. 14 doug_newcomb at fws.gov
---------------------------------------------------------------------------------------------------------
The opinions I express are my own and are not representative of the
official policy of the U.S.Fish and Wildlife Service or Dept. of the
Interior.   Life is too short for undocumented, proprietary data formats.
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