1

I would like to count number of layers in a stack with value equal to raster pixel value. Here is my current try:

r1 <- calc(s, fun=function(x){sum(x == r)})

I get two errors

Error in FUN(newX[, i], ...) : unused argument (na.rm = TRUE)

and

Error: cannot allocate vector of size 1.9 Mb

Where I'm going wrong?

2
  • how is r defined?
    – obrl_soil
    Dec 11, 2018 at 9:49
  • r is a raster file while s is a raster stack @obrl_soil
    – jmutua
    Dec 11, 2018 at 11:12

1 Answer 1

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Yeah ok, raster::calc() only operates on a single object, so your formula is essentially trying to total up all the occasions where one of your stack's cells equals a whole raster, which is never.

Try this: first, stack r and s. This means each pixel in the output stack becomes a vector where element 1 is the reference value and the rest are comparison values. Then run calc on that object, with a function like

function(x) {
  comp <- x[1]
  main <- x[2:length(x)]
  length(main[main == comp])
}

This should return a raster where each cell is a count of how many stack layers equal the overlying reference cell value.

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