Ratified Raster Brick

This is a script that takes selected fields (selected_fields) from a shape file and turns each into a raster. If the field is character-based categories, it ratifies the raster. At the end, you have a list of rasters. You can then bind these into a brick or perform other list-wise operations on them.

require(rgdal)
library(sf)
# The input file geodatabase
fgdb <- "land.gdb"

# Read the feature class
fc <- st_read(dsn=fgdb,layer="all_land")
forest <- read.csv("IDs_to_keep.csv")
world.map <- fc[fc$gridcode %in% forest$gridcode,]

library(raster)
ext <- extent(world.map)
gridsize <- 30
r <- raster(ext, res=gridsize)

selected_fields <- c("Own", "Cover", "Secondary")

library(fasterize)
test <- lapply(selected_fields, function(x) {
   myraster <- fasterize(world.map, r, field=x)
   names(myraster) <- x
   if(is.factor(world.map[,x][[1]])) {
      field <- x
      myraster <- ratify(myraster)
      rat <- levels(myraster)[[1]]
      rat[[field]] <- levels(world.map[,x][[1]])[rat$ID]
   levels(myraster) <- rat}
return(myraster)})