LOCAL DERIVATIVE ESTIMATION FOR SCATTERED DATA INTERPOLATION

In scattered data interpolation a surface through the given data point s is constructed. A class of methods requires triangulation of the dom ain with the data points at the vertices and definition of a local int erpolant over each triangle. In order to construct a smooth surface, i t is usual to employ certain derivative values at the vertices. If the se are not given, they can be prescribed by estimating the derivatives using the data points. We present here a method of derivative estimat ion by using a convex combination of all derivatives on related triang ular planes. The method has comparable accuracy to the existing method of least-squares minimization but with less computation.