See Also
    --------
    splprep, splrep, splint, sproot, splev
    UnivariateSpline, BivariateSpline

    Notes
    -----
    See `bisplev` to evaluate the value of the B-spline given its tck
    representation.

    If the input data is such that input dimensions have incommensurate
    units and differ by many orders of magnitude, the interpolant may have
    numerical artifacts. Consider rescaling the data before interpolation.

    References
    ----------
    .. [1] Dierckx P.:An algorithm for surface fitting with spline functions
       Ima J. Numer. Anal. 1 (1981) 267-283.
    .. [2] Dierckx P.:An algorithm for surface fitting with spline functions
       report tw50, Dept. Computer Science,K.U.Leuven, 1980.
    .. [3] Dierckx P.:Curve and surface fitting with splines, Monographs on
       Numerical Analysis, Oxford University Press, 1993.

    Examples
    --------
    Examples are given :ref:`in the tutorial <tutorial-interpolate_2d_spline>`.

    z!len(x)==len(y)==len(z) must hold.Nr^