def _get_area_def(self):
        """Get the area definition of the band."""
        cfac = np.int32(self.mda['cfac'])
        lfac = np.int32(self.mda['lfac'])
        coff = np.float32(self.mda['coff'])
        loff = self._get_line_offset()

        a = self.mda['projection_parameters']['a']
        b = self.mda['projection_parameters']['b']
        h = self.mda['projection_parameters']['h']
        lon_0 = self.mda['projection_parameters']['SSP_longitude']

        nlines = int(self.mda['number_of_lines'])
        ncols = int(self.mda['number_of_columns'])

        area_extent = self.get_area_extent((nlines, ncols),
                                           (loff, coff),
                                           (lfac, cfac),
                                           h)

        proj_dict = {'a': float(a),
                     'b': float(b),
                     'lon_0': float(lon_0),
                     'h': float(h),
                     'proj': 'geos',
                     'units': 'm'}

        area = geometry.AreaDefinition(
            AREA_NAMES[self.area_id]['short'],
            AREA_NAMES[self.area_id]['long'],
            'geosmsg',
            proj_dict,
            ncols,
            nlines,
            area_extent)

        return area
Get the area definition of the band.