def getDateIter(sysCode):
    """Return a list of dates given a coordinate system code
    """
    if sysCode > 0:
        # mean
        dateList = (1960, 2010)
    elif sysCode == -1:
        dateList = (0, 1960)
    else:
        # apparent topocentric or focal plane; 0 is the only reasonable choice
        dateList = (0,)
    return dateList