PyNIO

   1 # load Nio module
   2 import Nio
   3 
   4 # open netcdf file
   5 f = Nio.open_file('sresa1b_ncar_ccsm3_0_run1_200001.nc', 'r') # 'r' stands for "read rights"
   6 
   7 # check contents
   8 print f
   9 
  10 # get dimensions
  11 dimNames = f.dimensions.keys()
  12 
  13 # get the size of dimension
  14 dimSize = f.dimensions['dimName']
  15 
  16 # read single variable:
  17 pr = f.variables['pr']
  18 print pr
  19 
  20 # read variables contents
  21 pr_data = pr[:]
  22 print pr_data
  23 
  24 # print slice of the variable data
  25 slice = pr_data[0,::-1,:]
  26 
  27 # close file
  28 f.close()

   1 # create new file
   2 import Nio
   3 import numpy
   4 
   5 f = Nio.open_file('test.nc', 'w') # "w" stands for writing rights
   6 
   7 # create a dimension
   8 f.create_dimension('time',100)
   9 
  10 # create variable
  11 f.create_variable('temperature', 'i', ('time',)) # dimension 'time' must be created prior to this step
  12 
  13 # dimensions and variables can have same names
  14 f.create_variable('time', 'i', ('time',))
  15 
  16 # Dimension types:
  17 #    'd': 64 bit float
  18 #    'f': 32 bit float
  19 #    'l': long
  20 #    'i': 32 bit integer
  21 #    'h': 16 bit integer
  22 #    'b': 8 bit integer
  23 #    'S1': character 
  24 
  25 # Create an attribute 
  26 f.variables['temperature'].units = "K"
  27 
  28 # Add scaling factor and an offset
  29 # when the variable will be read, it will need to be multiplied by the scale_factor first and the added to the offset value
  30 f.variables['temperature'].scale_factor = 0.1
  31 f.variables['temperature'].add_offset = 273
  32 
  33 # create variable contents and assign it to the NetCDF variable
  34 temp = numpy.arange(0,100,1, dtype = numpy.int32)
  35 f.variables['temperature'][:] = temp
  36 
  37 time = numpy.arange(1000,1100,1, dtype = numpy.int32)
  38 f.variables['time'][:] = time
  39 
  40 f.close()