examples/grass_v2rast_count_example.R

In NINAnor/oneimpact: Tools for the assessment of the cumulative impacts of anthropogenic features in ecological studies

# not run
\dontrun{

  # libraries
  library(rgrass)
  library(terra)

  # Load vector data
  f <- system.file("vector/sample_area_cabins.gpkg", package = "oneimpact")
  cabins_vect <- terra::vect(f)
  # Load referemce raster data - for creation of GRASS project
  f <- system.file("raster/sample_area_cabins.tif", package = "oneimpact")
  cabins <- terra::rast(f)

  # connect to grass gis and create grass location
  # For linux or within OSGeo4W shell
  grassdir <- system("grass --config path", intern = TRUE)
  # grassdir <- system("grass78 --config path", intern = TRUE) # for GRASS 7.8
  # If you used the standalone installer in Windows
  # grassdir <- "C:\\Programs\\GRASS GIS 7.8" # Correct if the path GRASS version or path is different

  gisDB <- "." # create location and mapset in the working directory
  loc <- "ETRS_33N/" # name of the location
  ms <- "PERMANENT" # name of the mapset
  rgrass::initGRASS(gisBase = grassdir,
                    SG = cabins, # use map to define location projection
                    home = tempdir(),
                    override = TRUE,
                    gisDbase = gisDB,
                    location = loc,
                    mapset = ms)

  # add map to GRASS
  rgrass::write_VECT(cabins_vect, vname = "cabins_vect", flags = "o")

  # set region
  rgrass::execGRASS("g.region", vector = cabins_vect, res = "100", flags = c("p"))

  # rasterize with count, creating a new temp_vector
  cabins_count_name <- grass_v2rast_count("cabins_vect", output = "cabins_count",
                                          verbose = TRUE, overwrite = TRUE)

  # rasterize with count, without creating a temporary vector
  cabins_count_name <- grass_v2rast_count(cabins_vect_name, output = "cabins_count",
                                          column = "value",
                                          verbose = TRUE, overwrite = TRUE)

  # visualize
  rgrass::read_RAST(cabins_count_name, return_format = "terra")
  plot(main = "Number of private cabins")

  # remove rasters created
  # to_remove_vect <- c(test_region_name, cabins_vect_name)
  # to_remove_rast <- c(cabins_count_name)
  # rgrass::execGRASS("g.remove", type = "vect", name = to_remove_vect, flags = "f")
  # rgrass::execGRASS("g.remove", type = "rast", name = to_remove_rast, flags = "f")

}