code: def cutout_data(self, x1, y1, x2, y2, xstep=1, ystep=1, astype=None):
          
          view = np.s_[y1:y2:ystep, x1:x2:xstep]
          data = self._slice(view)
          if astype:
              data = data.astype(astype, copy=False)
          return data
docs: cut out data area based on coords.