[gdal-dev] Writing Pixel Functions with VRT

[Yves Jacolin (free)]

Le mercredi 21 décembre 2011 21:44:14, Even Rouault a écrit :
> Le mercredi 21 décembre 2011 20:41:04, Yves Jacolin (free) a écrit :
> > Hello,
> > 
> > I have some question about writing pixel functions with vrt files. I have
> > a netcdf file with two subset named U and V.
> > 
> > How can I process sqrt(U^2 + V^2) using this feature with vrt file?
> > 
> > * do I need to create a C file and build GADL with it?
> > * do I need to create a C file and locate it close to vrt file?
> 
> It depends on how you want to use those pixel functions. If it is in an
> application in C/C++ that you develop and that uses GDAL, then it is
> sufficient to place the pixel function in your code and register it.
> 
> If you want the pixel functions to be usable by existing GDAL utilities or
> third-party programs using GDAL (QGIS...), then a solution is to create a
> small shared library that will be loaded as a GDAL plugin. See
> http://trac.osgeo.org/gdal/ticket/3367 that has already a few functions.
> 
> You just need to make sure that the plugin is accessible through
> GDAL_DRIVER_PATH environmenet variable. No need for it to be close to the
> VRT file.
> 
> Or you can indeed hack GDAL itself and add it and register it.
> 
> > Thanks,
> > 
> > Y.
interesting it seems we can use Python pixel functions.

Y.
-- 
Yves Jacolin