CODEWITHSUNDEEP
rcoordinatesrasterr-rastercalc
Antoine Prince
Antoine Prince

Reputation: 31

Get raster cell coordinates using the 'calc' function in R

I am trying to run a 'calc' function in R and I can't seem to find a way to obtain the coordinates of the cell that is being processed. What I'm trying to do is simple : Using the 'calc' function on a binary raster (0 and 1)-- If the raster value is '0', then change to 'NA'. If the raster value is '1', then apply a series of processes for which I will need to cell coordinates to be stored into variables.

processAllCells = function(cell) {
  if (cell == 0) {
    cell = NA
    return(cell) 
  }
  else {
    cellCoords = coordinates(cell) ### This is what I'm trying to do. This does not work. See the error message.
    ### Here will go further processes using the cell coordinates.
    return(cell)
  }
}

outputRaster = calc(lake, processAllCells)

Error message :

Error in (function (classes, fdef, mtable)  : 
  unable to find an inherited method for function ‘coordinates’ for signature ‘"integer"’
In addition: Warning message:
In if (cell == 0) { :

 Error in (function (classes, fdef, mtable)  : 
  unable to find an inherited method for function ‘coordinates’ for signature ‘"integer"’

Thanks everyone!

Upvotes: 0

Views: 294

Answers (1)

Robert Hijmans
Robert Hijmans

Reputation: 47091

That is not possible. But you can make a RasterLayer with the x and y coordinates and used these in calc. 

library(raster)
r <- raster(nrow=10, ncol=10, values=1:100)
x <- init(r, "x")
y <- init(r, "y")

And then 

s <- stack(r, x, y)
#x <- calc(s, your-function)

Upvotes: 0

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