[GRASS-user] how to count number of occurrences of a specific category value in the neighborhood of a given pixel

Moritz Lennert mlennert at club.worldonline.be
Wed Nov 23 18:11:34 EST 2011

On 23/11/11 17:41, Marcello Gorini wrote:
> Moritz:
>     Hello,
>     Does anyone see an easy way to count the number of times a specific
>     category value occurs in a given neighborhood of a central pixel ?
> As always, there is surely a better way in GRASS (probably one single
> command), but you could binarize your map (1 for your desired category
> and zero for everything else) and then use r.neighbors method=sum
> size=desired_neighborhood.
> The result would be the desired count.

Thanks ! Yes, I came upon this solution myself in the meanwhile and I 
think it is the only one. Maybe something to script into a nice little 
frontend to r.neighbors where you give the map and the desired category 
and you receive a map of numbers of neighbours in return.


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