R/download_paleoclim.R

In pastclim: Manipulate Time Series of Climate Reconstructions

#' Download the paleoclim time series.
#'
#' This function downloads annual and monthly variables from the Paleoclim V1.0
#' dataset.
#' @param dataset the name of the dataset
#' @param bio_var the variable name
#' @param filename (NOT USED FOR THIS FUNCTION: the data come as zip of all bio
#'   variables, so we generate multiple files, not a single one)
#' @returns TRUE if the requested paleoclim variable was downloaded successfully
#'
#' @keywords internal

download_paleoclim <- function(dataset, bio_var, filename = NULL) {
  version <- "1.0.0" # version of the vrt so that we can change things later

  # compose download paths
  download_url <- filenames_paleoclim(
    dataset = dataset,
    bio_var = bio_var
  )

  # if we do not have a directory, create one
  paleoclim_dir <- file.path(get_data_path(), "paleoclim_1.0")
  if (!dir.exists(paleoclim_dir)) {
    dir.create(paleoclim_dir)
  }
  # and now download the files
  paleoclim_path <- file.path(paleoclim_dir, basename(download_url))
  # this server does not allow to resume downloads
  download_res <- curl::multi_download(download_url, # nolint we create download_res just in case
    destfiles = paleoclim_path
  )

  # create band description and time axis
  #  time_period_codes <- c("LH", "MH", "EH", "YDS", "BA", "HS1", "LIG") # nolint
  time_vector <- c(
    0, -2250, -6250, -10000, -12300, -13800, -15850,
    -21000, -130000
  )
  band_vector <- paste0("bio", sprintf("%02d", 1:19))
  resolution <- strsplit(dataset, "_")[[1]][3]
  # if resolution is 2.5, we need to change it to 2_5
  resolution <- gsub(".", "_", resolution, fixed = TRUE)
  resolution <- paste0(resolution, "in") # to get 10min
  # the zip with present day reconstructions has an additional directory
  # same for zip with LGM reconstructions
  paleoclim_path[1] <- file.path(paleoclim_path[1], resolution)
  paleoclim_path[8] <- file.path(paleoclim_path[8], resolution)
  # create a vrt for each variable
  for (i in seq_len(length(band_vector))) {
    # build the vsizip paths
    paleoclim_vsizip <- paste0("/vsizip/", file.path(
      paleoclim_path,
      paste0("bio_", i, ".tif")
    ))
    # TODO to add the really old time slices, we need to substitute these for
    # certain variables with a blank raster
    vrt_filename <- paste0(dataset, "_", band_vector[i], "_v", version, ".vrt")
    # nolint start
    # old terra code, something is wrong with macos options
    # create the vrt file
    # vrt_path <- terra::vrt(x = paleoclim_vsizip,
    #                        filename = file.path(get_data_path(),vrt_filename),
    #                        options="-separate", overwrite=TRUE, return_filename=TRUE)
    # nolint end
    vrt_path <- file.path(get_data_path(), vrt_filename)
    if (file.exists(vrt_path)) {
      file.remove(vrt_path)
    }
    sf::gdal_utils(
      util = "buildvrt",
      source = paleoclim_vsizip,
      destination = vrt_path,
      options = c("-separate")
    )
    # edit the vrt metadata
    edit_res <- vrt_set_meta(
      vrt_path = vrt_path,
      description = band_vector[i],
      time_vector = time_vector
    )
    if (!edit_res) {
      file.remove(vrt_path)
      stop(
        "something went wrong setting up ", band_vector[i],
        "\n the dataset wil need downloading again"
      )
    }
  }


  return(TRUE)
}