[gdal-dev] Quicklook creation with Python/GDAL

[Markus Reinhold]

Hej everyone,
currently I was able to finish a small Python project utilizing GDAL for 
creating quicklooks of satellite imagery. What I am doing right now is
retrieving the statistics of input bands, applying a standard deviation
stretch and saving the result as PNG-dataset. This works quite well,
however my problems start right here. To actually resize the created
dataset and to merge three separate bands into a single PNG-file I'm
using the Python Imaging Library, which needs single files to read from
in order to do any processing. There is no problem with small to
medium-sized images. But I'm running into trouble trying to create a
quicklook for some standard panchromatic Quickbird imagery (ca. 30000 x
30000 pixels, 0.6 m GSD at UInt16 -> about 1.9 GB file size) as the PNG
file that is created temporarily gets very big. The neccessary I/O
operations naturally take quite some time. So my question is the
following: Is there any possibility to do resizing a dataset with GDAL
means - to spare the creation of a temporary file?
Thank you very much for any ideas.
Regards,
Markus Reinhold

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Dipl.-Kartograph Markus Reinhold

Chair of Geoinformatics, Geohydrology and Modeling
Friedrich-Schiller-University Jena
Löbdergraben 32
D - 07743 Jena
Germany

Phone.: (+49)(0)3641 / 9 488 65
E-Mail: markus.reinhold at uni-jena.de
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