[gdal-dev] gdal_translate: set the CRS makes the output 10 times bigger

[Even Rouault]

Le jeudi 02 juin 2011 20:28:42, Andrés Maneiro a écrit :
> Thanks Even for the response, I suppose it has to do with your
> suggestions, but I don't know why, as I don't see any compression
> algorithm within gdalinfo output :/

ok, so it is well NBITS = 1 and actually uncompressed, and with 64x64 tiles.

So try :

gdal_translate -a_srs "EPSG:23029" original.tif output.tif -co NBITS=1 -co 
TILED=YES -co BLOCKXSIZE=64 -co BLOCKYSIZE=64

output.tif should have a similar size to  original.tif

> 
> Here the output of gdalinfo on the original tiff:
> 
> Driver: GTiff/GeoTIFF
> Files: 120135.tif
> Size is 12261, 9595
> Coordinate System is:
> PROJCS["UTM Zone 29N",
>      GEOGCS["ED_1950_16",
>          DATUM["ED_1950_16",
>              SPHEROID["International 1909",6378388,297.0000535480247]],
>          PRIMEM["Greenwich",0],
>          UNIT["degree",0.0174532925199433]],
>      PROJECTION["Transverse_Mercator"],
>      PARAMETER["latitude_of_origin",0],
>      PARAMETER["central_meridian",-9],
>      PARAMETER["scale_factor",0.9996],
>      PARAMETER["false_easting",500000],
>      PARAMETER["false_northing",0],
>      UNIT["metre",1,
>          AUTHORITY["EPSG","9001"]]]
> Origin = (560152.010000000009313,4794483.370000000111759)
> Pixel Size = (0.035418645400000,-0.035419541800000)
> Metadata:
>    TIFFTAG_SOFTWARE=IMAGINE TIFF Support
> Copyright 1991 - 1999 by ERDAS, Inc. All Rights Reserved
> @(#)$RCSfile: etif.c $ $Revision: 1.10.1.9.1.9.2.11 $ $Date: 2004/09/15
> 18:42:01EDT $
>    TIFFTAG_XRESOLUTION=1
>    TIFFTAG_YRESOLUTION=1
>    TIFFTAG_RESOLUTIONUNIT=1 (unitless)
>    AREA_OR_POINT=Area
> Image Structure Metadata:
>    INTERLEAVE=BAND
> Corner Coordinates:
> Upper Left  (  560152.010, 4794483.370) (  8d15'30.35"W, 43d17'59.98"N)
> Lower Left  (  560152.010, 4794143.519) (  8d15'30.49"W, 43d17'48.97"N)
> Upper Right (  560586.278, 4794483.370) (  8d15'11.08"W, 43d17'59.86"N)
> Lower Right (  560586.278, 4794143.519) (  8d15'11.22"W, 43d17'48.84"N)
> Center      (  560369.144, 4794313.445) (  8d15'20.78"W, 43d17'54.41"N)
> Band 1 Block=64x64 Type=Byte, ColorInterp=Palette
>    Image Structure Metadata:
>      NBITS=1
>    Color Table (RGB with 2 entries)
>      0: 0,0,0,255
>      1: 255,255,255,255
> 
> On 02/06/11 20:07, Even Rouault wrote:
> > Le jeudi 02 juin 2011 20:00:15, Andrés Maneiro a écrit :
> >> Hello devs,
> >> 
> >> I'm playing with GDAL to set the CRS of a set of geotiff files I was
> >> given to upload them to geoserver later.
> >> 
> >> These files, were generated using ArcGIS and it seems that the CRS set
> >> in the geotiff file header is not standar (at least, my geoserver
> >> 
> >> doesn't recognize them). What I did:
> >>    gdal_translate -a_srs "EPSG:23029" original.tif output.tif
> >> 
> >> After doing that, the size of the output is 5/10 times bigger than input
> >> (in some cases: from 10Mb to almost 110Mb). The only thing I see as
> >> different -using gdalinfo on both files- is the "Color Table". The
> >> former has 2 entries and the output has 256. Don't know if it's the
> >> source of the problem, just let you know in case it is useful.
> > 
> > Hum, it's likely that your original.tif was compressed. gdal_translate
> > without argument will generate an uncompressed file.
> > 
> > What is the output of gdalinfo on original.tif ? If you see a COMPRESS=
> > metadata keywords, you can try reusing it as a creation option.
> > 
> > It is also likely that your original.tif is a 1bit file.
> > 
> > So, guess blindly, I would try :
> > 
> > gdal_translate -a_srs "EPSG:23029" original.tif output.tif -co NBITS=1
> > -co COMPRESS=PACKBITS
> > 
> >> So, my question is: how could I generate an output file, with CRS set
> >> and with roughly the same size of the original?
> >> 
> >> best,
> >> amaneiro
> >> _______________________________________________
> >> gdal-dev mailing list
> >> gdal-dev at lists.osgeo.org
> >> http://lists.osgeo.org/mailman/listinfo/gdal-dev
> 
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