data-raw/chelsa/filenames_chelsa_trace21k.R

In EvolEcolGroup/pastclim: Manipulate Time Series of Palaeoclimate Reconstructions

filenames_chelsa_trace21k<- function(dataset, bio_var, version=NULL){
  if (dataset=="CHELSA_trace21k_1.0"){
    version <- "1.0" 
  }
  
  yr_id <- seq(0,-200,by=-1)
  
  # based on the variable, get the original var prefix and name for chelsa
  if (any("bio" %in% substr(bio_var,1,3))){
    var_prefix <- "bio"
    
    var_index <- paste0(var_prefix,
                        sprintf("%02d", 
                                as.numeric(substr(bio_var,nchar(bio_var)-1,nchar(bio_var)))))
  } else if (any("tem" %in% substr(bio_var,1,3))){
    var_prefix <- "tas"
    var_index <- paste0(var_prefix,"_",
                        sprintf("%02d", 
                                as.numeric(substr(bio_var,nchar(bio_var)-1,nchar(bio_var)))))
  } else if (any("pre" %in% substr(bio_var,1,3))){  
    var_prefix <- "pr"
    var_index <- paste0(var_prefix,"_",
                        sprintf("%02d", 
                                as.numeric(substr(bio_var,nchar(bio_var)-1,nchar(bio_var)))))
  }
  # create file names for a given variable
  chelsa_trace_root <- "https://os.zhdk.cloud.switch.ch/envicloud/chelsa/chelsa_V1/chelsa_trace"
  file.path(chelsa_trace_root, var_prefix, paste0("CHELSA_TraCE21k_",var_index,"_",yr_id,"_V",version,".tif"))
}


########################
# testing the file names are correct

foo <- filenames_chelsa_trace21k(dataset="CHELSA_trace21k_v1.0", bio_var = "bio01")
# check that a file exists
urlFileExist <- function(url){
  HTTP_STATUS_OK <- 200
  hd <- httr::HEAD(url)
  status <- hd$all_headers[[1]]$status
  list(exists = status == HTTP_STATUS_OK, status = status)
}
urlFileExist(foo[1])
# if we have several (but not too many), we could use
foo_exist <- lapply(foo, urlFileExist)

#terra::describe(foo[1])