R/ll_get_world.R

In giocomai/latlon2map: Facilitates matching lat/lon data with administrative units and other geographic shapes

#' Get countries as an sf object
#'
#' @param resolution Defaults to "60", for 1:60 Million. Available values: are 20, 10, 3, 1 (1 is highest quality available)-
#' @param year Defaults to 2020. Available values: 2020, 2016, 2013, 2010, 2006, 2001
#'
#' @return
#' @export
#'
#' @examples
ll_get_world <- function(resolution = "60",
                         year = 2020,
                         name = NULL) {
  resolution <- stringr::str_pad(
    string = resolution,
    width = 2,
    side = "left",
    pad = 0
  )
  usethis::ui_info("Source: https://ec.europa.eu/eurostat/web/gisco/geodata/reference-data/administrative-units-statistical-units/countries")
  usethis::ui_info("© EuroGeographics for the administrative boundaries")
  ll_create_folders(
    geo = "world",
    level = "country",
    resolution = resolution,
    year = year
  )

  rds_file <- ll_find_file(
    geo = "world",
    level = "country",
    resolution = resolution,
    year = year,
    name = "abl",
    file_type = "rds"
  )

  if (fs::file_exists(rds_file)) {
    return(readRDS(file = rds_file))
  }

  shp_folder <- ll_find_file(
    geo = "world",
    level = "country",
    resolution = resolution,
    year = year,
    name = "abl",
    file_type = "shp"
  )
  if (fs::file_exists(fs::path(shp_folder, paste0("CNTR_RG_", resolution, "M_", year, "_4326.shp"))) == FALSE) {
    zip_file <- ll_find_file(
      geo = "world",
      level = "country",
      resolution = resolution,
      year = year,
      name = "abl",
      file_type = "zip"
    )
    source_url <- paste0("https://ec.europa.eu/eurostat/cache/GISCO/distribution/v2/countries/download/ref-countries-", year, "-", resolution, "m.shp.zip")

    if (fs::file_exists(zip_file) == FALSE) {
      download.file(
        url = source_url,
        destfile = zip_file
      )
    }
    unzip(
      zipfile = zip_file,
      exdir = shp_folder
    )
    unzip(
      zipfile = fs::path(shp_folder, paste0("CNTR_RG_", resolution, "M_", year, "_4326.shp.zip")),
      exdir = shp_folder
    )
  }
  sf <- sf::read_sf(fs::path(shp_folder, paste0("CNTR_RG_", resolution, "M_", year, "_4326.shp"))) %>%
    sf::st_transform(crs = 4326)
  saveRDS(
    object = sf,
    file = rds_file
  )
  return(sf)
}