[GRASS-user] Eliminating values based on a null

GRASS GRASS user
1

Greetings

in my base map (called X) I have a few null values and, in Y map I want to eliminate pixels that match with null values in X. How can I do this? besides using mapcalc

Thanks
Jenny

2

Jenny:

in my base map (called X) I have a few null values and, in Y map I want to
eliminate pixels that match with null values in X. How can I do this?
besides using mapcalc

Hello Jenny,

I don't know if it is a coincidence, but your problem can be solved in the
same way as Kim's problem.

You can use the module r.series with the -n flag. It will propagate the
nulls among your input rasters. The method you use does not matter because
the -n flag overrides it. So it would be like this:

r.series -n input=X,Y output=Y_without_X_nulls method=average (or any
method)

Hope this helps,

Marcello.
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3

On 16/02/2011 18:12, Marcello Gorini wrote:

Jenny:

in my base map (called X) I have a few null values and, in Y map I want to
eliminate pixels that match with null values in X. How can I do this?
besides using mapcalc

r.series -n input=X,Y output=Y_without_X_nulls method=average (or any
method)

Just curious: What exactly is the advantage of NOT using mapcalc?

Hermann