[gdal-dev] Passing Python PixelFunctionArguments or kwargs from command line?

[Scott]

Thanks Even!

To re-iterate the value of passing arguments, here's a use case:

Say I have 20 years of climate data, 2001-2020, 1 raster per year. Using 
gdalbuildvrt I create a .vrt with all those rasters in chronological order.

Now say I want to stat a range of years, such as:

gdal_translate ... -oo PixelFunctionArguments="startYear=2012" -oo 
PixelFunctionArguments="endYear=2015"

In my .vrt python pixel function I might have something like this:

    stIdx = startYear - 2001
    endIdx = endYear - 2001
    ...
    np.someMethod(ar_in[stIdx:endIdx])


This would truly make VRT's dynamic. Instead of a temporal set of 
rasters, it could be a mix of elevation and land type. You get the idea.

Right now, it's easy enough to have the .vrt act as a template and do 
substitution with desired values. Passing arguments would make it very, 
very clean.

Thanks!
Scott

On 1/29/24 02:54, Even Rouault via gdal-dev wrote:
> Hi,
> 
> no, the values of pixel function arguments are hardcoded in the VRT. If 
> someone wanted to implement what you mention, that should rather be done 
> as open option (-oo) of the VRT driver
> 
> Even
> 
> Le 29/01/2024 à 08:29, Scott via gdal-dev a écrit :
>> With a python pixel function in a .vrt file, is it possible to pass 
>> values from the command line?
>>
>> Example:
>> gdal_translate ... -lco PixelFunctionArguments=? or -lco -kwargs=?
>>
>> Basically I want to change the 'min' and 'max' values on the command 
>> line:
>> <PixelFunctionArguments min="0" max="100" />
>>
>> Thanks!
>> Scott
>>
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