def interpolate_undefined_data(self, method='harmonic'):
    """
    Imputation of undefined data points in topography information that
    typically occurs in optical measurements.

    Parameters
    ----------
    self : SurfaceTopography.Topography or SurfaceTopography.UniformLineScan
        Input topography containing undefined data points.
    method : str
        Imputation methods. Options
           'harmonic': Interpolate with harmonic functions
        (Default: 'harmonic')
    """
    if method == 'harmonic':
        return self.interpolate_undefined_data_with_harmonic_function()
    else:
        raise ValueError(f"Unsupported imputation method '{method}'.")