Antw: arithmetic with layers from a raster stack/brick

I wouldn't recommend using this for general purpose, but this should work:

for (i in 1:nlayers(s)) {
  assign(names(s)[i], s[[i]])
}

Etienne


2013/2/28 Matteo Mattiuzzi <matteo.mattiuzzi at boku.ac.at>

Dear Ani,


Your "a" and "b" are not objects, they are the name the layers in your
object "s". So you can't treat it that way.


Maybe this is what you want?


require(raster)
r<- raster(nrows=2, ncols=2)
r[]<-1:ncell(r)
s<-stack(r,r)
names(s)<-c("a","b")



r1<- s[["a"]] + s[["b"]]


Matteo

aniruddha ghosh  28.02.13 21.26 Uhr >>>

Dear List,

I'm trying to perform some arithmetic operation with layers of a raster
object. What I'm trying is

require(raster)
r<- raster(nrows=2, ncols=2)
r[]<-1:ncell(r)
s<-stack(r,r)
names(s)<-c("a","b")

# now I want to add the layers of the raster "r" using their corresponding
names,i.e. "a" and "b" so that I get

r1<-a+b

I don't want to use subset (or any other methods) to define "a" or "b".
This may be very trivial, but I couldn't do it.

Any suggestions?

Thanks
--
Ani

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