#' Download the worldclim future time series.
#'
#' This function downloads annual and monthly variables from the WorldClim v2.1 dataset
#' for future projections.
#'
#' Note: the data come as tiffs each containing all bio (or prec/temp)
#' variables for a given time step. From these, we generate a vrt per variable. So,
#' since we download the full set for a give variable type, we create all the vrts
#' for that variable type (e.g. all the bio). We use the filename to get the version
#' name, and then at the end to check that we did generate it correctly given our
#' programmatic way of creating the names of all vrt files.
#' @param dataset the name of the dataset
#' @param bio_var the variable name
#' @param filename ()
#' @returns TRUE if the requested worldclim variable was downloaded successfully
#'
#' @keywords internal
download_worldclim_future <- function(dataset, bio_var, filename = NULL) {
# extract the version from the filename
version <- gsub("^.*_v([0-9]+\\.[0-9]+\\.[0-9]+)\\..*$", "\\1", filename)
# compose download paths
download_url <- filenames_worldclim_future(dataset=dataset,
bio_var = bio_var)
time_vector <- c(2030, 2050, 2070, 2090)
# create band vectors
# function to grab the number from the raster layer
if (grepl("bio", bio_var)) {
band_vector <- paste0("bio", sprintf("%02d", 1:19))
} else {
var_prefix <- substr(bio_var,nchar(bio_var)-1,nchar(bio_var))
band_vector <- paste0(var_prefix, sprintf("%02d", 1:12))
}
# if we do not have a directory, create one
worldclim_dir <- file.path(get_data_path(),"worldclim_2.1")
if(!dir.exists(worldclim_dir)){
dir.create(worldclim_dir)
}
# and now download the files (so the url is actually a local file)
worldclim_url <- file.path(worldclim_dir,basename(download_url))
download_res <- curl::multi_download(download_url,
destfiles = worldclim_url#, resume = TRUE
)
if(any(!download_res$success)){
stop("something went wrong downloading the data; try again")
}
# create a vrt for each variable
for (i in seq_len(length(band_vector))){
vrt_path <- file.path(get_data_path(), paste0(dataset,"_",band_vector[i],"_v",version,".vrt"))
# create the vrt file
# we capture warnings from the vrt to make sure that all is well
# withCallingHandlers({
# vrt_path <- terra::vrt(x = worldclim_url,
# filename = vrt_path,
# options=c("-b", i,"-separate"), overwrite=TRUE, return_filename=TRUE)
# }, warning = function(w) {
# if (!grepl("Only the first one",w)){
# file.remove(vrt_path)
# stop("vrt creation failed with ", w,"\n try to redownload this dataset")
# }
# invokeRestart("muffleWarning")
# })
withCallingHandlers({
sf::gdal_utils(
util = "buildvrt",
source = worldclim_url,
destination = vrt_path,
options = c("-b", i,"-separate","-overwrite")
)
}, warning = function(w) {
if (!grepl("Only the first one",w)){
file.remove(vrt_path)
stop("vrt creation failed with ", w,"\n try to redownload this dataset")
}
invokeRestart("muffleWarning")
})
######################################################################
# in gdal <3.8, the -b is ignored, and only the first band is used
# so, we edit the SourceBand for each band
x<- xml2::read_xml(vrt_path)
band_nodes <- xml2::xml_find_all(x, ".//SourceBand")
xml2::xml_text(band_nodes) <- as.character(i)
xml2::write_xml(x, vrt_path)
## end of workaround
######################################################################
# edit the vrt metadata
edit_res <- vrt_set_meta(vrt_path = vrt_path,
description = band_vector[i],
time_vector = time_vector,
time_bp = FALSE)
if (!edit_res){
file.remove(vrt_path)
stop("something went wrong setting up this dataset", "\n the dataset will need downloading again")
}
}
if (!file.exists(vrt_path)){
stop("something went wrong setting up this dataset", "\n the dataset will need downloading again")
}
return(TRUE)
}
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