A Rational Spline for Preserving the Shape of Positive Data

In Computer Aided Geometric Design (CAGD), it is often needed to produce a positivity–preserving curve according to the given positive data. The main focus of this work is to address the problem of visualizing positive data in such a way that its display looks smooth and pleasant. A rational cubic spline function with three shape parameters has been developed. Simple data dependent constraints are derived for single shape parameter to preserve the positivity through positive data. Remaining two shape parameters are provided extra freedom to user for modification of curves as desired. The scheme is local, computationally economical and time saving as compared to existing schemes. The curve scheme under discussion is attained 1 C continuity.