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<p>On 02/08/2011 12:01, Peter Hopfgartner wrote:
<blockquote cite="mid:4E37BCE5.3070000@r3-gis.com" type="cite">On
08/02/2011 09:01 AM, Mathieu Baudier wrote:
<br>
<blockquote type="cite">
<blockquote type="cite">I do not know of any direct drawback,
except that internal libjpeg and
<br>
libtiff/libgeotiff are used, instead of the system shared
libs.
<br>
</blockquote>
Frank Warmerdam advised against using the internal libtiff
back in October 2010:
<br>
<a class="moz-txt-link-freetext" href="http://lists.osgeo.org/pipermail/el/2010-October/000119.html">http://lists.osgeo.org/pipermail/el/2010-October/000119.html</a>
<br>
(the same would probably apply for libjpeg I guess)
<br>
</blockquote>
We could think about a separate gdal, e.g. gdal-il, package
with internal libs, with bigTIFF and 12 bit enabled. BTW,
UbuntuGIS is using internal libs, too.
<br>
</blockquote>
</p>
<p><br>
</p>
<p>Hi Peter:</p>
<p>I did a quick (amateur) test of jpeg 12 this morning and I must
say I was surprised with the results. I started with a 1.4 GB tiff
ortho photo, which I also have as an ECW image. The ECW is about
64MB. </p>
<p>I used the OSGeo4W installation of gdal with the libjpeg that
supports 12 bit, and I made two compressed tiffs. The regular jpeg
compression came down to about 75 MB, a bit larger than the ECW,
but it's quality was a bit fuzzy with color changes in the pixels.
(Of course ECW is also lossy, introducing changes in the pixel
coloring, but keeping "sharpness"). </p>
<p>The 12 bit jpeg-compressed tiff came down to about 120 MB, only
twice the size of the ECW, but it was almost indistinguishable
from the original tiff! Both in coloring and sharpness. That was
very impressive, I must say.</p>
<p>I don't know where the jpeg2000 format is going (if anwhere).
For now this 12-bit jpeg compression looks like an ideal
alternative to struggling with the closed ECW format on one hand,
or the unwieldy file sizes of uncompressed tiff on the other.</p>
<p><br>
</p>
<p>Best, Micha</p>
<p> </p>
<p><br>
</p>
<p>
<blockquote cite="mid:4E37BCE5.3070000@r3-gis.com" type="cite">Peter
<br>
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</blockquote>
</p>
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