[gdal-dev] Kakadu JP2 Output Overviews possible?

[Even Rouault]

Selon "Zermeno, Robert J CIV NAVAIR, 472100D" <robert.zermeno at navy.mil>:

> GDAL Community,
>
> I noticed GDAL has a utility program gdaladdo which embeds new overviews to a
> supplied file.  Does gdal have a utility program that allows me to extract
> overviews to a file?

Yes, it is a debug utility, called dumpoverviews, that is not compiled by
default. You will have to download GDAL sources, compile them, and then go to
the "apps" directory and : make dumpoverviews (Linux/Unix) or nmake /f
makefile.vc dumpoverviews.exe (Windows)

The source http://trac.osgeo.org/gdal/browser/trunk/gdal/apps/dumpoverviews.cpp
will answer all your questions.

I'd note that JP2 is a bit special. The full resolution image and the overviews
are mixed in the JP2 datastream. The choice of overviews levels exposed by GDAL
is rather arbitrary.