[gdal-dev] Gdal_calc.py with more than 26 input files

Even Rouault even.rouault at spatialys.com
Thu Jul 16 16:13:34 PDT 2015

On Thursday 16 July 2015 20:38:44 Jukka Rahkonen wrote:
> Hi,
> Have a look at this gis.stackexchange question:
> http://gis.stackexchange.com/questions/149006/does-gdal-calc-only-support-26
> -input-raster-files-at-a-time
> So, what users can do if they have more than 26 input files?

Hi Jukka,

The easiest way is the one suggested in of the gis.stackexchange questions: 
extend the AlphaList array with new letters (I think you could put any string 
actually that doesn't conflict with other options)

But when you have more than 26 input files, it is dubious that you really want 
to individually identify them with a particular letter/name. As in one of the 
examples, you likely just want to apply a global operation on them, like sum, 
mean, .... So they would be better passed as a lis
t so as to be able to build a 3 dimension numpy array, so you can do things 

--input foo.tif bar.tif ... --calc "rasters.mean(axis=0)"

And you could also still reference a particular raster with rasters[i] syntax

(To be clear: the above is not something currently available)


> -Jukka Rahkonen-
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