Returns true if the variable is a time series feature type.

    :param netCDF4.Dataset nc: An open netCDF dataset
    :param str variable: name of the variable to check

def is_timeseries(nc, variable):
    '''
    Returns true if the variable is a time series feature type.

    :param netCDF4.Dataset nc: An open netCDF dataset
    :param str variable: name of the variable to check
    '''

    # x, y, z, t(o)
    # X(o)
    dims = nc.variables[variable].dimensions

    cmatrix = coordinate_dimension_matrix(nc)
    for req in ('x', 'y', 't'):
        if req not in cmatrix:
            return False
    if len(cmatrix['x']) != 0:
        return False
    if len(cmatrix['y']) != 0:
        return False
    if 'z' in cmatrix and len(cmatrix['z']) != 0:
        return False
    timevar = get_time_variable(nc)

    # time has to be a coordinate variable in this case
    if cmatrix['t'] != (timevar,):
        return False
    if dims == cmatrix['t']:
        return True
    return False