text: #!/usr/bin/env python
  import numpy as np
  import matplotlib as mpl
  mpl.use('Agg')
  import matplotlib.pyplot as plt
  
  fname = 'sts.cube.plane16'
  data = np.genfromtxt(fname+'.dat')
  
  # for plotting with matplotlib
  data = data.swapaxes(0,1)[::-1]
  
  fig = plt.Figure(figsize=(4,4))
  #ax = fig.add_subplot(111, aspect=0.5)
  #fig.add_subplot(111,aspect='equal')
  plt.xlabel('y [$\AA$]')
  plt.ylabel('U [V]')
  
  extent = [0,20,-3,1]
  
  cax = plt.imshow(data, extent=extent, cmap='gray',
               aspect=4.0)
  
  #cbar = fig.colorbar(cax, format='%.2e')
  #cbar.set_label('LDOS')
  
  outfile = fname+'.png'
  print("Plotting into {}".format(outfile))
  plt.savefig(outfile, dpi=200)
  