old_contents: #!/usr/bin/env python
  
  import sys
  import argparse
  
  import numpy as np
  import netCDF4 as nc
  import matplotlib.pyplot as plt
  from matplotlib import animation
  
  """
  This script makes a fluid animation using NetCDF data.
  """
  
  def main ():
  	
  	# Setup arguments.
  	parser = argparse.ArgumentParser()
  	parser.add_argument('input_file',help="Input file containing our data")
  	parser.add_argument('field_name',help="Data field to animate")
  	args = parser.parse_args()
  	
  	# Open netCDF file (arg.input_file).
  	f = nc.Dataset(args.input_file)
  	vorticity = f.variables['vorticity_z']
  	# vorticity dimension: Time, st_ocean (pressure), yt_ocean (latitude), xt_ocean (longitude)
  	vorticity = vorticity[:]
  	
  	#fig = plt.figure()
  	#images = []
  	
  	# Generate the plot at pressure level = 0
  	for t in range(0,vorticity.shape[0]):
  		plt.imshow(vorticity[t,0,:,:])
  		#img = plt.imshow(vorticity[t,0,:,:])
  		#images.append([img])
  		# To show plot immediately, use:
  		# plt.show()
  		# Save the plot as an image file
  		plt.savefig('vorticity'+str(t).zfill(3)+'.png')
  		plt.close()
  
  	#ani = animation.ArtistAnimation(fig,images,interval=20)
  	#plt.show()
  	
  	# Close the netcdf file.
  	f.close()
  	
  	print "Completed..."
  	return True
  
  if __name__=="__main__":
  	sys.exit(main())
  
new_contents: #!/usr/bin/env python
  
  import sys
  import argparse
  
  import numpy as np
  import netCDF4 as nc
  import matplotlib.pyplot as plt
  from matplotlib import animation
  
  """
  This script makes a fluid animation using NetCDF data.
  """
  
  def main ():
  	
  	# Setup arguments.
  	parser = argparse.ArgumentParser()
  	parser.add_argument('input_file',help="Input file containing our data")
  	parser.add_argument('field_name',help="Data field to animate")
  	args = parser.parse_args()
  	
  	# Open netCDF file (arg.input_file).
  	f = nc.Dataset(args.input_file)
  	vorticity = f.variables['vorticity_z']
  	# vorticity dimension: Time, st_ocean (pressure), yt_ocean (latitude), xt_ocean (longitude)
  	vorticity = vorticity[:]
  	
  	fig = plt.figure()
  	images = []
  	
  	# Generate the plot at pressure level = 0
  	for t in range(0,vorticity.shape[0]):
  		#plt.imshow(vorticity[t,0,:,:])
  		img = plt.imshow(vorticity[t,0,:,:])
  		images.append([img])
  		# To show plot immediately, use:
  		# plt.show()
  		# Save the plot as an image file
  		#plt.savefig('vorticity'+str(t).zfill(3)+'.png')
  		#plt.close()
  
  	ani = animation.ArtistAnimation(fig,images,interval=20)
  	plt.show()
  	
  	# Close the netcdf file.
  	f.close()
  	
  	print "Completed..."
  	return True
  
  if __name__=="__main__":
  	sys.exit(main())
  
subject: modify script to show movie instead