[gdal-dev] Does CCITTFax-Compression of GeoTiffs work for you?

[ivan.lucena at pmldnet.com]

Hi Tom,

As long as I know GeoTiff CCITT 4 should work well in GDAL. 

>    TIFFTAG_SOFTWARE=IrfanView

Is it possible that "IrfanView" is producing a corrupted or out of standard CCITT?

Have you try to check the integrity of that files in another software? 

And what if you gdal_translate the successful LZW file to CCITT 4? Does it works?

Just some ideas...

Ivan

>  -------Original Message-------
>  From: Tom Kazimiers <2voodoo at gmx.de>
>  Subject: [gdal-dev] Does CCITTFax-Compression of GeoTiffs work for you?
>  Sent: Jan 13 '08 13:52
>  
>  Hi there,
>  
>  I asked this question already two month ago and would like to give it another try.
>  I am using GDAL 1.4.3 and esp. GeoTiff for reading and displaying
>  GeoTiffs on Windows CE.
>  I successfully managed it to display GeoTiff Files that are LZW
>  compressed - other formats seem not to work.
>  The error message I get when trying to load CCITTFax (3 or 4 - both do
>  not work) compressed images is:
>  
>  GetBlockRef failed at X block offset 0, Y block offset 0
>  
>  RasterIO still returns 0 (so it seems as there occured no error - but
>  CPLGetLastErrorMsg() returns the message above.)
>  gdalinfo returns for the working image:
>  
>  Driver: GTiff/GeoTIFF
>  Size is 62, 68
>  Coordinate System is `'
>  Metadata:
>    TIFFTAG_SOFTWARE=IrfanView
>    TIFFTAG_XRESOLUTION=508
>    TIFFTAG_YRESOLUTION=508
>    TIFFTAG_RESOLUTIONUNIT=2 (pixels/inch)
>  Image Structure Metadata:
>    COMPRESSION=LZW
>  Corner Coordinates:
>  Upper Left  (    0.0,    0.0)
>  Lower Left  (    0.0,   68.0)
>  Upper Right (   62.0,    0.0)
>  Lower Right (   62.0,   68.0)
>  Center      (   31.0,   34.0)
>  Band 1 Block=62x68 Type=Byte, ColorInterp=Palette
>    Metadata:
>      NBITS=1
>    Color Table (RGB with 2 entries)
>      0: 128,255,0,255
>      1: 251,13,0,255
>  
>  For the same image (just compressed with CCITTFax4 - and black/white
>  colors) it returns:
>  Driver: GTiff/GeoTIFF
>  Size is 62, 68
>  Coordinate System is `'
>  Metadata:
>    TIFFTAG_SOFTWARE=IrfanView
>    TIFFTAG_XRESOLUTION=508
>    TIFFTAG_YRESOLUTION=508
>    TIFFTAG_RESOLUTIONUNIT=2 (pixels/inch)
>  Image Structure Metadata:
>    COMPRESSION=CCITTFAX4
>  Corner Coordinates:
>  Upper Left  (    0.0,    0.0)
>  Lower Left  (    0.0,   68.0)
>  Upper Right (   62.0,    0.0)
>  Lower Right (   62.0,   68.0)
>  Center      (   31.0,   34.0)
>  Band 1 Block=62x68 Type=Byte, ColorInterp=Palette
>    Metadata:
>      NBITS=1
>    Color Table (RGB with 2 entries)
>      0: 255,255,255,255
>      1: 0,0,0,255
>  
>  
>  Everything is identical, but the the compression tag.
>  Do you have any hint what might have gone wrong?
>  
>  Thanks in advance,
>  Tom
>  
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