R/filenames_chelsa_present.R

In pastclim: Manipulate Time Series of Climate Reconstructions

#' Generate file names to download the chelsa present dataset
#'
#' This function creates a vector of paths needed to download the CHELSA present
#' dataset
#' @param dataset the name of the dataset of interest (currently unused)
#' @param bio_var the variable of interest
#' @returns a vector of times, one per band
#'
#' @keywords internal
filenames_chelsa_present <- function(dataset, bio_var) {
  var_index <- substr(bio_var, nchar(bio_var) - 1, nchar(bio_var))

  if ("bio" == substr(bio_var, 1, 3)) {
    var_prefix <- "bio"
    var_index <- paste0(var_prefix, as.numeric(var_index)) # strip leading 0
  } else if (length(grep(pattern = "npp", bio_var))) {
    var_prefix <- "bio"
    var_index <- "npp"
  } else if (length(grep(pattern = "temperature_min", bio_var))) {
    var_prefix <- "tasmin"
    var_index <- paste0(var_prefix, "_", var_index)
  } else if (length(grep(pattern = "temperature_max", bio_var))) {
    var_prefix <- "tasmax"
    var_index <- paste0(var_prefix, "_", var_index)
  } else if (length(grep(pattern = "temperature_", bio_var))) {
    var_prefix <- "tas"
    var_index <- paste0(var_prefix, "_", var_index)
  } else if ("pre" == substr(bio_var, 1, 3)) {
    var_prefix <- "pr"
    var_index <- paste0(var_prefix, "_", var_index)
  }
  # compose download paths
  chelsa_root <- "https://os.zhdk.cloud.switch.ch/chelsav2/GLOBAL/climatologies/1981-2010/" # nolint
  paste0(chelsa_root, var_prefix, "/CHELSA_", var_index, "_1981-2010_V.2.1.tif")
}