Return the corresponding line

        Args:
            lat (int): latitude in degree

        Returns:
            Correponding line

def line_id(self, lat):
        ''' Return the corresponding line

        Args:
            lat (int): latitude in degree

        Returns:
            Correponding line

        '''
        if self.grid == 'WAC':
            line = np.rint(1.0 + self.LINE_PROJECTION_OFFSET -
                           self.A_AXIS_RADIUS * np.pi * lat / (self.MAP_SCALE * 1e-3 * 180))
        else:
            line = np.rint(float(self.LINE_PROJECTION_OFFSET) - float(self.MAP_RESOLUTION)
                           * (lat - float(self.CENTER_LATITUDE))) + 1
        return self._control_line(line)