Update to a previous post: cutting multiple rasters with a multi-polygon shapefile

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A little while ago I posted here a function which was enormously useful for me (and I thought it might be for others to). At the time, I needed to cut many rasters by a multipolygon shapefile and create rasters with the result of this operation.

However, recently, I provided some advice to a fellow Geekcologist and realized that the function needed to be slightly tweaked.

Here is the new code (the ID field in the shapefile attribute table must be “id”).

crop_save <- function(origin_folder, pattern, destination_folder, name_sub_folder, crop_areas, name_crop_areas){
  file_list <- list.files(path = origin_folder, pattern)
  #Create folder
  how_many_areas <- nrow(crop_areas)
  #Create raster stack
  raster_stack <- stack() 
  #File paths
  paths1 <- paste0(origin_folder,file_list)
  #Load rasters to stack
  for(i in 1:length(file_list)){
    raster_stack <- stack(raster_stack, raster(paths1[i]))  
  names_list <-  eval(parse(text=name_crop_areas))
  numbers <- 1:length(names_list)
  names_list <- paste0(as.character(numbers),"_polygon_", names_list)
  polyRR_list <- list()
  for(x in 1: nrow(crop_areas)){
    pol1 <- assign(names_list[x],crop_areas[x,])
    polyRR_list[[x]] <- pol1
  for(j in 1:nlayers(raster_stack)){
    dir.create(paste0(destination_folder,"/",name_sub_folder, "/", names(raster_stack)[j]))
    for(k in 1:length(polyRR_list)){
      a <- crop(raster_stack[[j]], polyRR_list[[k]])
      a <- mask(a,polyRR_list[[k]], filename = paste0(destination_folder,"/",
                                                      name_sub_folder, "/", names(raster_stack)[j], "/",polyRR_list[[k]]$id, ".tif"))

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