[GRASS-dev] Creating / reading in random sample of raster values in Python script

[Paulo van Breugel]

On 25 March 2017 20:21:18 Luca Delucchi <lucadeluge at gmail.com> wrote:

> Il 25/mar/2017 20:07, "Paulo van Breugel" <p.vanbreugel at gmail.com> ha
> scritto:
>
> Hi,
>
>
> Hi,
>
>
> For a script I am working on, I am looking for a way to select a X number
> of raster cells and their values into a numpy array. I can create a layer
> with r.random, and read in that layer into a numpy array, but I rather
> avoid having to read in the whole raster layer. I can also from within the
> script run r.random  to generate a raster layer, r.stats to export the
> resulting raster layer as a text file (with n flag), and than read in the
> text file in Python. But I wonder if there is not a more direct way to
> accomplish this..
>
>
> You can read col and row from GRASS Region and use random python function
> to calculate random x and y and later query a pygrass raster object
>
Thanks. And what if I have a mask or null values in the target raster.

>
> Cheers,
>
> Paulo
>
>
> Cheers
> Luca
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