R/cmsaf.hist.R

In cmsafvis: Tools to Visualize CM SAF NetCDF Data

#' Plotting routine designed for the CM SAF R Toolbox.
#'
#' This function renders a histogram plot of two variables.
#' 
#'@param var1 Name of the first NetCDF variable (character).
#'@param infile1 Filename of the first input NetCDF file. This may include the directory
#'  (character).
#'@param var2 Name of the second NetCDF variable (character).
#'@param infile2 Filename of the second input NetCDF file. This may include the directory
#'  (character).
#'@param outfile1 Filename of the first output NetCDF file. This may include the directory
#'  (character).
#'@param outfile2 Filename of the second output NetCDF file. This may include the directory
#'  (character).
#'@param plot.out logical; if TRUE, the plot will be stored in the same folder as outfile1. 
#'  If FALSE, the plot will not be saved.
#'@param nc34 NetCDF version of output file. If \code{nc34 = 3} the output file will be
#'  in NetCDFv3 format (numeric). Default output is NetCDFv4.
#'@param overwrite logical; should existing output file be overwritten?
#'@param verbose logical; if TRUE, progress messages are shown
#'@param toolbox logical; if TRUE, toolbox mode enabled. The two files are adjusted in space 
#'  and time so that they can be plotted.
#'@param nc1 Alternatively to \code{infile1} you can specify the input as an
#'  object of class `ncdf4` (as returned from \code{ncdf4::nc_open}).
#'@param nc2 Alternatively to \code{infile2} you can specify the input as an
#'  object of class `ncdf4` (as returned from \code{ncdf4::nc_open}).
#'
#'@return Two NetCDF files are written.
#'@export
#'
#'@family 1d visualization 
#'
cmsaf.hist <- function(var1, infile1, var2, infile2, outfile1, outfile2, plot.out = FALSE, nc34 = 4, overwrite = FALSE, verbose = FALSE, toolbox = FALSE, nc1 = NULL, nc2 = NULL) {
  gc()
  calc_time_start <- Sys.time()
  
  if(overwrite){
    if(file.exists(outfile1)){
      unlink(outfile1)
    }
    if(file.exists(outfile2)){
      unlink(outfile2)
    }
  }
  
  cmsafops::cmsaf.adjust.two.files(var1, infile1, var2, infile2, outfile1, outfile2, nc34, overwrite, FALSE, nc1 = nc1, nc2 = nc2)
  
  if(!toolbox) {
    id1 <- ncdf4::nc_open(outfile1)
    data1 <- try(ncdf4::ncvar_get(id1, var1, collapse_degen = FALSE))
    time <- try(ncdf4::ncvar_get(id1, "time"))
    t_unit <- ncdf4::ncatt_get(id1, "time", "units")$value
    date.time <- as.character(cmsafops::get_time(t_unit, time))
    
    varname <- ncdf4::ncatt_get(id1, var1, "long_name")$value
    if (varname == 0)
      (varname <- ncdf4::ncatt_get(id1, var1, "standard_name")$value)
    if (varname == 0)
      (varname <- var1)
    
    unit <- ncdf4::ncatt_get(id1, var1, "units")$value
    if (unit == 0)
      (unit <- "-")
    
    xlabel <- paste0(varname, " [", unit, "]")
    
    id2 <- ncdf4::nc_open(outfile2)
    data2 <- try(ncdf4::ncvar_get(id2, var2, collapse_degen = FALSE))
    
    plot_filepath <- dirname(outfile1)
    
    # pattern <- "[^\\/]+(\\.nc)$" # regular exp. to extract filenames
    # regex1 <- regmatches(infile1, regexpr(pattern, infile1))
    # regex2 <- regmatches(infile2, regexpr(pattern, infile2))
    # Equivalent to above and works for URLs.
    regex1 <- get_basename_vis(infile1, nc = nc1)
    regex2 <- get_basename_vis(infile2, nc = nc2)
    for(i in seq_along(time)) {
      if(plot.out) {
        plot_filename <- paste0("cmsaf_histogram_plot_", date.time[i], ".png")
        if(file.exists(paste0(plot_filepath, "/", plot_filename))){
          unlink(paste0(plot_filepath, "/", plot_filename))
        }
        grDevices::png(paste0(plot_filepath, "/", plot_filename), width = 1024, height = 1024)
      }
      
      graphics::hist(data1[,,i], main = varname, xlab = xlabel,
                     col = grDevices::rgb(91, 127, 149, maxColorValue = 255, alpha = 170))
      graphics::hist(data2[,,i], main = "title",
                     col = grDevices::rgb(230, 50, 50, maxColorValue = 255, alpha = 100), add =TRUE)
      leg.txt <- c(regex1, regex2)
      textsize <- 1.2
      graphics::legend("topright", leg.txt, pch = 15, 
                       col = c(grDevices::rgb(91, 127, 149, maxColorValue = 255, alpha = 170), 
                               grDevices::rgb(230, 50, 50, maxColorValue = 255, alpha = 100)),
                       cex = textsize)
      if(plot.out)
        grDevices::dev.off()
    }
    ncdf4::nc_close(id1)
    ncdf4::nc_close(id2)
  }
  calc_time_end <- Sys.time()
  if (verbose) message(cmsafops::get_processing_time_string(calc_time_start, calc_time_end))
}