code: def plot_vzx(self, colorbar=True, cb_orientation='vertical',
                   cb_label=None, ax=None, show=True, fname=None, **kwargs):
          
          if cb_label is None:
              cb_label = self._vzx_label
  
          if ax is None:
              fig, axes = self.vzx.plot(colorbar=colorbar,
                                        cb_orientation=cb_orientation,
                                        cb_label=cb_label, show=False, **kwargs)
              if show:
                  fig.show()
  
              if fname is not None:
                  fig.savefig(fname)
              return fig, axes
  
          else:
              self.vzx.plot(colorbar=colorbar, cb_orientation=cb_orientation,
                            cb_label=cb_label, ax=ax, **kwargs)
docs: Plot the Vzx component of the tensor.
  
          Usage
          -----
          x.plot_vzx([tick_interval, xlabel, ylabel, ax, colorbar,
                      cb_orientation, cb_label, show, fname])
  
          Parameters
          ----------
          tick_interval : list or tuple, optional, default = [30, 30]
              Intervals to use when plotting the x and y ticks. If set to None,
              ticks will not be plotted.
          xlabel : str, optional, default = 'longitude'
              Label for the longitude axis.
          ylabel : str, optional, default = 'latitude'
              Label for the latitude axis.
          ax : matplotlib axes object, optional, default = None
              A single matplotlib axes object where the plot will appear.
          colorbar : bool, optional, default = True
              If True, plot a colorbar.
          cb_orientation : str, optional, default = 'vertical'
              Orientation of the colorbar: either 'vertical' or 'horizontal'.
          cb_label : str, optional, default = '$V_{zx}$'
              Text label for the colorbar.
          show : bool, optional, default = True
              If True, plot the image to the screen.
          fname : str, optional, default = None
              If present, and if axes is not specified, save the image to the
              specified file.
          kwargs : optional
              Keyword arguements that will be sent to the SHGrid.plot()
              and plt.imshow() methods.