def make_figure_basename(local_station_id,
                         reference_station_id,
                         xy_or_yx,
                         matlab_or_fortran):
    """
    
    Parameters
    ----------
    local_station_id: str
        station label
    reference_station_id: str
        remote reference station label
    xy_or_yx: str
        mode: "xy" or "yx"
    matlab_or_fortran: str
        "matlab" or "fortran".  A specifer for the version of emtf.

    Returns
    -------
    figure_basename: str
        filename for figure

    """
    station_string = f"{local_station_id}"
    if reference_station_id:
        station_string = f"{station_string}_rr{reference_station_id}"
    figure_basename = (
        f"synthetic_{station_string}_{xy_or_yx}_{matlab_or_fortran}.png"
    )
    return figure_basename