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# Reclassifying raster stack based on condition and other layers using R? I want to reclassify raster`r1`in the following form:

• all the values that are larger than`r2`to be`1`
• all the values that are less than`r3`to be`0`
• all the rest of the values to be equal to`r4`

I use overlay to set the values for the first two conditions, but I can't do that for the third one. I am also interested to know how to put all these in one function.

``library(raster) r1 <- raster(nrow=5, ncol=5) r1 <- setValues(r1, runif(ncell(r1))) r2 <- setValues(r1, runif(25 ,0.6,0.9)) r3 <- setValues(r1, runif(25 ,0.2,0.4)) r4 <- setValues(r1, runif(25 ,1,2)) x <- overlay(r1, r2, fun=function(x,y){ x[x>y] <- 1; x}) x2 <- overlay(x, r3, fun=function(x,y){ x[x``

To put this into a vectorized function you can use ifelse. If you stack your rasters then you do not need to piecemeal the reclassification and can apply a function to the stack.

Prepare data

``library(raster) r1 <- raster(nrow=5, ncol=5) r <- stack(setValues(r1, runif(ncell(r1))), setValues(r1, runif(25 ,0.6,0.9)), setValues(r1, runif(25 ,0.2,0.4)), setValues(r1, runif(25 ,1,2)))``

Write reclassification function

``rc <- function(x1,x2,x3,x4) { ifelse( x1 > x2, 1, ifelse( x1 < x3, 0, x4) ) }``

Apply function to raster stack

``r.class <- overlay(r, fun=rc)``

The bracket extract operators work on rasters in R. So you dont need to use setValues or overlay. I would do this:

``r1[r1 > r2] <- 1 r1[r1 < r3] <- 0 r1[!(r1 > r2 | r1 < r3)] <- r4[!(r1 > r2 | r1 < r3)]``

This should work if all of your rasters are the same extent and resolution.