C1 Rational Quadratic Trigonometric Interpolation Spline for Data Visualization

A new C-1 piecewise rational quadratic trigonometric spline with four local positive shape parameters in each subinterval is constructed to visualize the given planar data. Constraints are derived on these free shape parameters to generate shape preserving interpolation curves for positive and/or monotonic data sets. Two of these shape parameters are constrained while the other two can be set free to interactively control the shape of the curves. Moreover, the order of approximation of developed interpolant is investigated as O(h(3)). Numeric experiments demonstrate that our method can construct nice shape preserving interpolation curves efficiently.