[R-sig-Geo] Using "rasterize" with parallel...

[Guillermo E. Ponce-Campos]

GetXYfromRaster <- function (vraster.template, vshp.file, vext) {

if (nchar(vshp.file) < 1) {
    vshp.file <- tk_choose.files(caption="Select shapefile...")
    vshp.file <- readShapeSpatial(vshp.file)
  } else {
    vshp.file <- readShapeSpatial(vshp.file)
  }

  ## Cluster for parallelization
  cl <- makeCluster(detectCores()-2)
  registerDoParallel(cl)
  if (nchar(vraster.template) < 1) {
    vraster.template <- tk_choose.files(caption="Select raster template...")
    mc <- foreach (i = 1:1, .packages = "raster") %dopar% {
      vraster.template <- raster(vraster.template)
      vraster.template <- crop (vraster.template, vext)
    }
  } else {
    mc <- foreach (i = 1:1, .packages = "raster") %dopar% {
       vraster.template <- raster(vraster.template)
       vraster.template <- crop (vraster.template, vext)
    }
  }
  mc <- foreach (i = 1:1, .packages = "raster") %dopar% {
     vshp.crop <- crop(vshp.file, vraster.template)
     vrasterized <- rasterize(vshp.crop, vraster.template, field="OBJECTID")

  }
  vxy.coords <- coordinates(vrasterized)

  stopCluster(cl)

  return (as.data.frame(vxy.coords))

}

I'm getting the following error when I call that function...

Error in { :
  task 1 failed - "unable to find an inherited method for function extent
for signature "character""

Doing the traceback, the error comes from the call to "rasterize".  Is it
possible to use rasterize in this way?

Any hint?

Guillermo

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