根据其位置设置栅格NA的像素

Question

I have a raster which has 50+ bands. What I would like to is to search for all pixel == 0 within the first band of the raster. Following I would like to set all of these pixels NA in the other raster bands as well. Thus, I don't have to do the search for 0 again 50+ times. Here is my example:

cl_input <- brick("sometif")
for(i in 1:nlayers(cl_input)){
    print(names(cl_input[[i]]))
    cl_input[[i]][cl_input[[i]] == 0] <- NA   
}

I hope I stated out my need clearly =)

Thanks in advance, cheers

Answer 1

You can use the mask method; using the first layer as the mask, and by setting the maskvalue to zero.

library(raster)
b <- brick(nrow=2, ncol=2, nl=3)
values(b) <- matrix(c(0,1,1),4,3)
values(b)
##     layer.1 layer.2 layer.3
##[1,]       0       1       1
##[2,]       1       1       0
##[3,]       1       0       1
##[4,]       0       1       1

d <- mask(b, b[[1]],  maskvalue=0)
values(d)
##     layer.1 layer.2 layer.3
##[1,]      NA      NA      NA
##[2,]       1       1       0
##[3,]       1       0       1
##[4,]      NA      NA      NA

Answer 2

No need for a loop here. You can search for 0 in all layers at once:

cl_input <- brick("sometif")
cl_input[cl_input == 0] <- NA