On 25-03-17 23:11, Laurent C. wrote:
Hello,
If you need a fixed number of points, you might do a while loop that
randomly generate coordinates then add the point only if the array is
not null at those coordinates.
Thanks, I'll give that a try. Will also see how this compares with using
r.random/r.what in terms of speed.
Laurent
On 25 Mar 2017 13:55, "Paulo van Breugel" <[email protected]
<mailto:[email protected]>> wrote:
On 25 March 2017 20:21:18 Luca Delucchi <[email protected]
<mailto:[email protected]>> wrote:
> Il 25/mar/2017 20:07, "Paulo van Breugel"
<[email protected] <mailto:[email protected]>> 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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