nc2ascii

#!/usr/bin/env python

# import gdal
# import math
# from gdalconst import *
# import struct
from netCDF4 import Dataset
# import matplotlib.pylab as mpl
import numpy as np
import sys
# import glob
# fill in times.
# from datetime import datetime, timedelta
# from netCDF4 import num2date, date2num
from argparse import ArgumentParser



def convert_var(filename, varname):
  

  infile=Dataset(filename,"r")
  var = infile.variables[varname]
  x = infile.variables["x"]
  y = infile.variables["y"]

  newname="%s_%s.asc"%(filename[:-3],varname)
  ncols = len(x)
  nrows = len(y)
  x_off = x[0]-(x[1]-x[0])/2.
  y_off = y[0]-(y[1]-y[0])/2.
  cellsize = x[1]-x[0]
#  NODATA_VALUE = var._FillValue
  NODATA_VALUE=-9999
  outfile=open(newname,"w")
  outfile.write ("ncols %i\n"%ncols)
  outfile.write("nrows  %i\n"%nrows)
  outfile.write("xllcorner %i\n"%x_off)
  outfile.write("yllcorner %i\n"%y_off)
  outfile.write("cellsize %i\n"%cellsize)
  outfile.write("NODATA_VALUE %i\n"%(int(NODATA_VALUE)))
  ascii= [" ".join([ "%.2f"%y for y in x  ])+"\n" for x in np.squeeze(var[:])]
  ascii.reverse()
  outfile.writelines(ascii)
  outfile.close()

  
  # print (dir(driver))
  # src_ds = gdal.Open( template )
  # outDataset = driver.CreateCopy(newname, src_ds, 0 )
  # print outDataset
  # outBand = outDataset.GetRasterBand(1)
  # outBand.WriteArray(np.squeeze(var[:]), 0,0)
  
  


def parse_args():
  parser = ArgumentParser()
  parser.description = "Convert netcdf to ascii"
  parser.add_argument("FILE", nargs='*')
  parser.add_argument("-v", "--variable", 
                    help='''Variables to convert, e.g. = 'usurf,cbar,...'.''', default=None)

  options = parser.parse_args()
  return options


def main(argv):
  options = parse_args()
  #  print (dir(options))
  convert_var(options.FILE[0], options.variable)
  
if __name__ == "__main__":
    main(sys.argv)