[gdal-dev] VRT creation from Python, adding existing geotiff as bands

[Rémi Cura]

Thank for the fast answers !

@EvenRouault  : thanks for the snippet, I wasn't aware of this mechanism to
transmit option trough python dictionary.
It should most likely be sufficient for my needs, even if I don't
understand it fully yet.
I had read the tutorial but failed to translate it from C++ to python.
I'm still _very_ reticent to create XML for VRT in python, I don't see how
it could be safe and age well.

@Anton :
thanks for the lib, I'll look into vrt.py
<https://github.com/nansencenter/nansat/blob/master/nansat/vrt.py> to try
to understand how to add an existing tiff file as a band to vrt.
I don't think I need "SourceTransferType", because the type of the vrt band
will be the same as the type of the existing geotiff file.

Cheers,
Rémi-C


2015-02-16 15:11 GMT+01:00 Anton Korosov <anton.korosov at nersc.no>:

> Dear Rémi,
>
> you may want to look at our Python package NANSAT (https://github.com/
> nansencenter/nansat) which we build around the GDAL and especially VRT.
> We even have a separate class VRT() for creating, changing and using VRT
> files.
> More specific regarding your question, you can try to use the
> SourceTransferType parameter of the VRT. Search for this keyword at
> http://gdal.org/gdal_vrttut.html
>
> Regards!
> Anton
>
>
> On 16/02/15 14:13, Rémi Cura wrote:
>
>> Hey dear list,
>> this is my first post here,
>> so sorry if I'm asking something obvious.
>>
>> (I noticed the 2 previous mail thread regarding python and VRT).
>>
>> I wrote python functions to convert a numpy structured array to several
>> gdal rasters.
>>
>> A numpy structured array is a 2D pixel array, but each pixel has in fact
>> several values of possibly different type (like band).
>> For instance a pixel dtype can be [float32,uint16,Float64].
>>
>> I want to convert this array to raster(s).
>> First I tried to create one raster with several bands,
>> but GeoTiff cannot handle bands with different pixel type (or I didn't
>> find how).
>>
>> I concluded that I must create several rasters, and put them all as
>> bands in a VRT.
>>
>> So far I have been able to create several geoTiff raster of various type
>> corresponding to the numpy structured array.
>>
>> Now, I don't know how to create from python the VRT that unites all this
>> rasters.
>>
>> When I try to write in a VRT raster band I get errors.
>>
>> I am well aware that I could create the XML directly from python, but it
>> feels like a pretty bad architecture idea.
>>
>> Anybody knows how to do this /and/or has comments about this task?
>>
>> Many Thanks,
>> Rémi-C
>>
>>
>>
>>
>> _______________________________________________
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>> gdal-dev at lists.osgeo.org
>> http://lists.osgeo.org/mailman/listinfo/gdal-dev
>>
>>
>
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