A bivariate rational interpolation method with parameters was created in an earlier work which was based on function values only, and this spline is with bicubic numerator and biquadratic denominators. This paper will deal with the bounded property, approximation property and the point control method of the interpolating surface. It is proved that the values of the interpolating function in the interpolation region are bounded no matter what the parameters might be. Also, the approximation expression of the interpolation are derived. More important is that the values of the interpolating funct...
