R/ReadNetCDF4.R

In rSQM: Statistical Downscaling Toolkit for Climate Change Scenario using Non Parametric Quantile Mapping

ReadNetCDF4 <- function(wdir, ncfile) {

  tmp <- getwd()
  setwd(wdir)

  fin <- ncdf4::nc_open(ncfile)

  # Get the file information into array
  finfo <- capture.output(print(fin))

  # Get the dimension, variable name, dimension names
  nrow=length(finfo[])
  for(i in 1:nrow){
    str <- finfo[i]
    str <- stringr::str_split_fixed(str,"float ",2)[2]
    if(!(str == "")){
      varnm <- stringr::str_split_fixed(str, stringr::fixed("["), 2)[1]
      str <- stringr::str_split_fixed(str, stringr::fixed("["), 2)[2]
      str <- stringr::str_split_fixed(str, stringr::fixed("]"), 2)[1]
      dimsz <- stringr::str_count(str, stringr::fixed(",")) + 1
      dimnms <- stringr::str_split_fixed(str, stringr::fixed(","), dimsz)
    }
  }

  lon <- ncdf4::ncvar_get(fin, dimnms[1])
  lat <- ncdf4::ncvar_get(fin, dimnms[2])
  variable <- ncdf4::ncvar_get(fin,varnm)

  # In the case of multiple layers, get the first layer (surface ) values
  if(varnm == 'hur'){
    variable <- variable[,,1,]
  }

  outList <- list("x"=lon, "y"=lat, "var"=variable, "fin"=finfo)

  ncdf4::nc_close(fin)
	
  setwd(tmp);rm(tmp)
  return(outList)

}