<p>ok, can you please book a trac ticket?<br>
(maybe there is one already)</p>
<p>On Feb 3, 2012 2:04 PM, "Peter Hopfgartner" <<a href="mailto:peter.hopfgartner@r3-gis.com">peter.hopfgartner@r3-gis.com</a>> wrote:<br>
><br>
> Hi Evan<br>
><br>
> Indeed, the external libtiff is used and is version libtiff-3.9.4-1.el6_0.3.x86_64.<br>
> In the mean time I did a quick compile of gdal-1.9.0 with internal libtiff and the square disappeared.<br>
> Probably it would be a wise decision to switch to libtiff4 quickly, as far as ELGIS is concerned.<br>
><br>
> Thanks,<br>
><br>
> Peter<br>
><br>
> On 02/03/2012 01:41 PM, Even Rouault wrote:<br>
>><br>
>> Peter,<br>
>><br>
>> Does ELGIS GDAL uses internal libtiff (4.0beta) or external libtiff (3.8 or 3.9)<br>
>> ? I guess it is external libtiff, and then it could explain the issues you have<br>
>> with overviews and JPEG compression. There have been fixes in libtiff 4 to<br>
>> better support that situation (multiple IFDs with compression). Altertantively,<br>
>> you could probably workaround that by generating external overviews (add -ro to<br>
>> the gdaladdo command line), but no guarantees. By the way, the --config<br>
>> COMPRESS_OVERVIEW JPEG --config INTERLEAVE_OVERVIEW PIXEL --config<br>
>> JPEG_QUALITY_OVERVIEW 90 options only apply to external overviews, not internal<br>
>> ones.<br>
>><br>
>>> I'm doing quite some experiments with GDAL and image compression these days<br>
>>><br>
>>> I do have an issue with geotiff 1.3/gdal 1.8.1 on CentOS 6 with packages<br>
>>> from ELGIS. The story goes like this:<br>
>>><br>
>>> I create tiffs with<br>
>>><br>
>>> gdal_translate -of GTiff -co COMPRESS=JPEG -co JPEG_QUALITY=90<br>
>>> -co "TILED=YES" -co "BLOCKXSIZE=512" -co "BLOCKYSIZE=512"<infile><br>
>>> <outfile><br>
>>><br>
>>> and then add overviews with (I do have to add the overlays in distinct<br>
>>> steps, otherwise gdaladdo aborts with an error message).<br>
>>><br>
>>> gdaladdo --config COMPRESS_OVERVIEW JPEG --config INTERLEAVE_OVERVIEW<br>
>>> PIXEL --config JPEG_QUALITY_OVERVIEW 90 -r average<outfile> 3<br>
>>> gdaladdo --config COMPRESS_OVERVIEW JPEG --config INTERLEAVE_OVERVIEW<br>
>>> PIXEL --config JPEG_QUALITY_OVERVIEW 90 -r average<outfile> 9<br>
>>> gdaladdo --config COMPRESS_OVERVIEW JPEG --config INTERLEAVE_OVERVIEW<br>
>>> PIXEL --config JPEG_QUALITY_OVERVIEW 90 -r average<outfile> 27<br>
>>> gdaladdo --config COMPRESS_OVERVIEW JPEG --config INTERLEAVE_OVERVIEW<br>
>>> PIXEL --config JPEG_QUALITY_OVERVIEW 90 -r average<outfile> 81<br>
>>><br>
>>> (Trying with power-of-2-steps gives the same result. If I drop all<br>
>>> options from gdaladdo: same result).<br>
>>><br>
>>> I'll create a WMS service with MapServer 5.6.7 and do get a big red<br>
>>> square in the image. The square is "fixed" to the geografical position,<br>
>>> e.g. if I move the extend the square moves too. The square is situated<br>
>>> in the corner of the tiff file.<br>
>>> It appears only at some scales. If I change it very slightly, the square<br>
>>> remqins, if I change for more then approx 1%, it disappears.<br>
>>><br>
>>> I've put the two images at<br>
>>><br>
>>> <a href="http://www.r3-gis.com/gdal_issues/tiff_with_jpegcompression_and_overviews.jpeg">http://www.r3-gis.com/gdal_issues/tiff_with_jpegcompression_and_overviews.jpeg</a><br>
>>> and<br>
>>> <a href="http://www.r3-gis.com/gdal_issues/tiff_with_nocompression_and_overviews.jpeg">http://www.r3-gis.com/gdal_issues/tiff_with_nocompression_and_overviews.jpeg</a><br>
>>> .<br>
>>><br>
>>> The problem disappears if I do not run gdaladdo on the images or when I<br>
>>> do not use Jpeg compression:<br>
>>><br>
>>> gdal_translate -of GTiff -co "TILED=YES" -co "BLOCKXSIZE=512" -co<br>
>>> "BLOCKYSIZE=512"<origfile> <targetfile><br>
>>><br>
>>> There are some hits for<br>
>>><br>
>> <a href="http://www.google.com/search?client=ubuntu&channel=fs&q=mapserver+artefacts+in+raster+gdal&ie=utf-8&oe=utf-8">http://www.google.com/search?client=ubuntu&channel=fs&q=mapserver+artefacts+in+raster+gdal&ie=utf-8&oe=utf-8</a>,<br>
>>><br>
>>> but mostly related to older versions of GDAL and without resolution.<br>
>>><br>
>>><br>
>>> Thanks,<br>
>>><br>
>>> Peter<br>
>>><br>
>>> --<br>
>>><br>
>>> Peter Hopfgartner<br>
>>> R3 GIS Srl - GmbH<br>
>>> <a href="http://www.r3-gis.com">www.r3-gis.com</a><br>
>>><br>
>>><br>
>>> _______________________________________________<br>
>>> gdal-dev mailing list<br>
>>> <a href="mailto:gdal-dev@lists.osgeo.org">gdal-dev@lists.osgeo.org</a><br>
>>> <a href="http://lists.osgeo.org/mailman/listinfo/gdal-dev">http://lists.osgeo.org/mailman/listinfo/gdal-dev</a><br>
>>><br>
>><br>
><br>
><br>
> -- <br>
> Peter Hopfgartner<br>
> R3 GIS Srl - GmbH<br>
> web : <a href="http://www.r3-gis.com">www.r3-gis.com</a><br>
><br>
><br>
> _______________________________________________<br>
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</p>