[gdal-dev] GTiff optimisation

[Yves Jacolin]

Matt,

Thanks for the link but I already read this page and I have only one process 
(assign projection information).

Anyway, this is always good to read this information !

List,

I successfully assigned my projection information but still have some 
difference in the file size. This is not so important but I wanted to understand 
the reason. Idea welcome :)

Another question: I have 2 000 ECW files (40 Mo each), 49 ECW files (1 Go each) 
and 2 ECW files (2 Go each). I worked first on 2 Go ECW file, it takes around 1 
day to assign the projection information in the files.

Do you think this is normal? How can I improve this? 

Thanks.

Y.

Le mardi 30 août 2011 18:46:53, Matt Wilkie a écrit :
> Yves,  it's best to use gdalwarp without any compression options and
> then use gdal_translate as a last step to apply the compression. See
> http://trac.osgeo.org/gdal/wiki/UserDocs/GdalWarp#GeoTIFFoutput-coCOMPRESSi
> sbroken for more.
> 
> cheers,
> 
> matt wilkie
> --------------------------------------------
> Geomatics Analyst
> Information Management and Technology
> Yukon Department of Environment
> 10 Burns Road * Whitehorse, Yukon * Y1A 4Y9
> 867-667-8133 Tel * 867-393-7003 Fax
> http://environmentyukon.gov.yk.ca/geomatics/
> --------------------------------------------
> 
> On 30/08/2011 4:22 AM, Yves Jacolin wrote:
> > Hello,
> > 
> > I am converting GTiff to GTiff in order to add projection and
> > georeferencing information in the header. I am using gdalwarp with some
> > flags, mailny -co flags. I have some question about this.
> > 
> > Here is my command line:
> > 
> > gdalwarp -co "COMPRESS=PACKBITS" -co "PHOTOMETRIC=MINISWHITE" -co
> > "NBITS=1" - s_srs "EPSG:2154" -t_srs "EPSG:2154" input.tif output.tif
> > 
> > 1.  File size: input.tif and output.tif have different file size, output
> > file is 50 % bigger than the input file. Is it normal?
> > 
> > 2. If I use gdalinfo on my output file, I have no information about
> > MINISWHITE parameter while I have it in the input file. Am I using this
> > creation option correctly? This issue could be related to the first
> > item?
> > 
> > 3. I also have a "AREA_OR_POINT=Area" item in my output from gdalinfo,
> > what does it means?
> > 
> > gdal version: GDAL 1.7.3, released 2010/11/10
> > 
> > thanks,
> > 
> > Y.
> 
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-- 
Yves Jacolin

http://yjacolin.gloobe.org