sptools: Additional Functions for Spatial* Objects

Documented in gadm

# ------------------------------------------------------------------------------
#' Download corresponding files
#'
#' From a vector of one or multiple string identify which files need to be
#' downloaded
#'
#' @param file file to downloaded (absolute path)
#' @param alt_path alternative path to the internal library that may contains
#' the download files
#' @param format character string, format to downlaod, either sp or sf
#' @noRd
download_file <- function(file, alt_path, format, force) {
  alt_file <- paste0(alt_path, "/", basename(file))
  if (file.exists(alt_file)) {
    ndfile <- alt_file[file.exists(alt_file)] # files not to download
    file.copy(ndfile, paste0(dirname(file), "/", basename(ndfile)))
  }
  if ((file.exists(file) & isTRUE(force))) {
    download.file(paste0("https://biogeo.ucdavis.edu/data/gadm3.6/R", format,
                         "/", basename(file)), file, mode = "wb")
  }
  if (any(!file.exists(file))) {
      file <- file[!file.exists(file)]  # file to download
      download.file(paste0("https://biogeo.ucdavis.edu/data/gadm3.6/R", format,
                           "/", basename(file)), file, mode = "wb")
  }
}

#-------------------------------------------------------------------------------
#' Get GADM data
#'
#' Download sp or sf file format from GADM in the internal library of the
#' package and/or a specified path and/or a temporary path.
#'
#' If the \code{save} and/or \code{intlib} arguments are \code{NULL}, it will
#' be asked interactively to the user to decide where to store the file. The
#' function will return a message if the file is already present in the internal
#' library or in the specify path. The function will only download the file if
#' it's not available in the internal library and the path inputted but the
#' download can be forced (argument \code{force == TRUE}) if the file present
#' has a problem.
#' \cr\cr
#' The table will show you the interaction between these two arguments
#' to download and path to saved sp or sf file format from GADM:
#' \cr
#' \verb{
#' |--intlib = FALSE
#' |    |-- save = FALSE
#' |    |     *-- no disk memory
#' |    |-- save = TRUE
#' |    |     |-- path = NULL
#' |    |         *-- working directory
#' |    |     |-- path = PATH
#' |    |         *-- PATH
#' |    |-- save = NULL
#' |    |     |-- `Do you want to save the map in another location?`
#' |    |         |-- yes
#' |    |             |-- `Can you provide the path to the location?`
#' |    |             |    *-- working directory (default)
#' |    |             |    *-- PATH
#' |    |         |-- no (default)
#' |--intlib = TRUE
#' |    |-- save = FALSE
#' |    |     *-- internal library
#' |    |-- save = TRUE
#' |    |     |-- path = NULL
#' |    |         *-- internal library + working directory
#' |    |     |-- path = PATH
#' |    |         *-- internal library + PATH
#' |    |-- save = NULL
#' |    |     |-- `Do you want to save the map in another location?`
#' |    |         |-- yes
#' |    |             |-- `Can you provide the path to the location?`
#' |    |             |    *-- internal library+ working directory (default)
#' |    |             |    *-- internal library+ PATH
#' |    |         |-- no (default)
#' |--intlib = NULL
#'      |-- `Do you want to save the map in your internal library?`
#'            *-- no >> intlib = FALSE
#'            *-- yes >> intlib = TRUE
#'}
#'
#'
#' @param country character string, name of the country to download
#' @param format character string, format to downlaod, either sp or sf
#' @param level integer between 0 and 3 or 4, level of the administrative
#'   borders, 0 being country borders.
#' @param intlib boolean, specifies whether the downloaded file should be saved
#' in the library of packages. If \code{NULL}, it will be asked interactively.
#' By default \code{TRUE}, see `Details` for more information.
#' @param save boolean, specifies whether the downloaded file should be saved
#' in a specific path or not. If \code{NULL}, it will be asked interactively.
#' By default \code{FALSE}, see `Details` for more information.
#' @param path character string, path to save the downloaded file. If
#' \code{NULL}, the file will be saved in the working directory. By default
#' \code{NULL}, see `Details` for more information.
#' @param force boolean, force to download the file even if already in the path.
#' By default \code{FALSE}.
#'
#' @author Marc Choisy, Lucie Contamin
#'
#' @importFrom countrycode countrycode
#' @importFrom utils download.file installed.packages
#' @examples
#'
#' # to download Cambodia country administrative boundaries
#' kh <- gadm("Cambodia", "sf", 0)
#'
#' #' # to download Vietnam only in the working directory
#' \dontrun{
#' vn <- gadm("Vietnam", "sf", 0, intlib = FALSE, save = TRUE)
#' }
#'
#' @export
gadm <- function(country, format, level, intlib = TRUE, save = FALSE,
                 path = NULL, force = FALSE) {

  # prerequisite
  country <- countrycode(country, "country.name", "iso3c")
  file <- paste0("gadm36_", country, "_", level, "_", format, ".rds")
  dirname <- paste0(installed.packages()["sptools", "LibPath"],
                     "/sptools/extdata/")
  if (!dir.exists(dirname)) dir.create(dirname)
  pfile <- paste0(dirname, file)

  # path preparation
  if (isTRUE(save) & is.null(path)) path <- paste0(getwd(), "/")
  if (isFALSE(save)) {
    tmp <-  paste0(tempdir(), "/")
    dir.create(tmp, showWarnings = FALSE)
    path <- tmp
  }
  if (is.null(save)) {
    message(cat("\n Do you want to save ", file, " in another location",
                " (yes/ no (default)) \n"))
    ans <- readline("Selection: ") #nocov start
    if (ans == "yes") {
      message(cat("\n Can you provides the path to the location? \n",
                  "By default, working direction"))
      ans2 <- readline("Path: ")
      if (ans2 == "") {
        path <- getwd()
      } else {
        path <- ans2
        if (!dir.exists(path)) dir.create(path, showWarnings = FALSE)
      } #nocov end
    }
    if (ans %in% c("no", "")) {
      tmp <- paste0(tempdir(), "/")
      dir.create(tmp, showWarnings = FALSE)
      path <- tmp
    }
  }
  path <- paste0(path, "/", file)

  # download file
  if (any(!file.exists(pfile))) {
    if (isFALSE(intlib) & file.exists(path) & isFALSE(force)) {
        message(cat(
          "The file '", file, "' is already present in ",
          unique(dirname(path)), sep = ""))
    }
    download_file(pfile, dirname(path), format = format, force = force)

  } else if (file.exists(pfile)){
    if (isTRUE(force)) {
      download_file(pfile, dirname(path), format = format, force = force)
    } else {
      message(cat(
        "The file '", file, "' is already present in the internal library.",
        sep = ""))
    }
  }

  # Save the file in the correct path
  file.copy(pfile, path)
  if (is.null(intlib)) {
    message(cat("\n Do you want to download ", file,
                " in your internal library?", "  (yes (default) / no)? \n"))
    ans <- readline("Selection: ")
    if (ans == "no") {
      intlib <- FALSE #nocov
    }
  }

  if (isFALSE(intlib)) {
    file.remove(pfile)
    pfile <- path
  }
  data <- readRDS(pfile)

  # remove temporary direction
  if (exists("tmp")) {
    if (file.exists(paste0(tmp, file))) file.remove(paste0(tmp, file))
  }
  data
}