[R-sig-Geo] clip a raster layer to a mask layer using raster algebra in R?

[Christian Willmes]

Sorry, I had an error in the main command.

It should be:

gebco_clipped <- ifelse(RSLmask, gebco, NA)

But it still gives the same error.

Best,
Christian

Am 06.12.18 um 09:37 schrieb Christian Willmes:
> Hello,
>
> this should be normally a very basic simple one-liner, but I can't get 
> my head around it. I only find solutions for cliping a raster against 
> a vector, but none for clipping a raster against a raster mask.
>
> I want to clip a layer to a mask. In GRASS GIS r.mapcalc the syntax is:
>
> result = if(RSLmask, gebco, null())
>
> This clips the GEBCO dataset to the extent of the given raster mask 
> 'rslmask'. The result raster has heigt values within the raster mask 
> extent, the rest of the raster layer has NULL or NA values.
>
> In R I did the following, but it does not work as expected:
>
> gebco <- raster(gebco2014) #load raster
>
> RSLmask <- gebco >= 0  #create mask layer
>
> RSL <- ifelse(RSLmask, 1, NA)
>
> The last command gives an error about vector type 'S4'?!
>
> >In is.na(test) :
>   >is.na() auf nicht-(Liste oder Vektor) des Typs 'S4' angewendet
>
> So, in short: what is the R way to simply clip a raster to a raster mask?
>
> Thanks and best regards,
> Christian
>
> PS: If found many solutions for clipping a raster to a vector polygon, 
> but this is not what I want.
>
-- 
Dr. Christian Willmes	
AG GIS & Fernerkundung      | GIS & RS Group
Geographisches Institut     | Institute of Geography
Universität zu Köln         | University of Cologne
Tel.: +49 (0)221 470 6234
http://www.geographie.uni-koeln.de/14126.html
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