[R-sig-Geo] Mask from raster with less RAM

[Sourav Sarkar]

Dear Frederico,
With the very little experience that I have with raster data, it seems to
me (maybe I am wrong) that `crop' is computationally easier than `mask'. If
the crop command serves your purpose, maybe you can try:
r2.mask <- crop(r2, pol)

Kind regards,

বুধ, ১২ আগস্ট, ২০২০ তারিখে ২:১৩ AM টায় এ Frederico Faleiro <
fvfaleiro using gmail.com> লিখেছেন:

> Dear all,
>
> I would like to generate a mask from a raster, but my workflow needs a lot
> of RAM to process big rasters. I need this polygon mask to use in another's
> rasters.
> Do you know another approach that needs less RAM?
>
> # reproducible example
> library(raster)
> # read data to create mask
> r <- raster(system.file("external/test.grd", package="raster"))
> r[!is.na(r)] <- 1
> pol <- rasterToPolygons(r, dissolve = T) #  a lot of RAM to process the
> data
> # apply the mask in another raster
>  r2 <- raster(extent(r), res(r))
> r2[ ] <- 1
> r2.mask <- mask(r2, pol)
>
> Cheers!
>
> --
> Frederico Faleiro
> Postdoctoral Researcher in the INCT-EECBio (https://www.eecbio.ufg.br/)
> Department of Ecology | Institute of Biological Science | Federal
> University of Goiás | Brazil
> RG: https://www.researchgate.net/profile/Frederico_Faleiro
> CV: http://lattes.cnpq.br/4926404840659003
>
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>
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-- 
Sourav Sarkar,
Assistant Professor,
School of Arts and Sciences,
Ahmedabad University

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