docs: def getfigsize(self, opt):
          '''calculate appropriate sizes for the subfigures
          '''
          if opt.xmin is None:
              opt.xmin = self.plotman.grid.grid['x'].min()
          if opt.xmax is None:
              opt.xmax = self.plotman.grid.grid['x'].max()
          if opt.zmin is None:
              opt.zmin = self.plotman.grid.grid['z'].min()
          if opt.zmax is None:
              opt.zmax = self.plotman.grid.grid['z'].max()
          if np.abs(opt.zmax - opt.zmin) < np.abs(opt.xmax - opt.xmin):
              self.sizex = 2 / 2.54
              self.sizez = self.sizex * (
                      np.abs(opt.zmax - opt.zmin) / np.abs(opt.xmax - opt.xmin))
          else:
              self.sizez = 2 / 2.54
              self.sizex = 0.5 * self.sizez * (
                      np.abs(opt.xmax - opt.xmin) / np.abs(opt.zmax - opt.zmin))
              print('schmal')
          # add 1 inch to accommodate colorbar
          self.sizex += 4 * .5
          self.sizex *= 4
          self.sizez *= self.rows
          self.sizez += 5