Visualization of Rainfall Data Distribution Using Quintic Triangular Bezier Patches

This paper discusses the use of a C^2 interpolant which is positive everywhere and the need to preserve positivity in the case of visualization of rainfall data distribution of Peninsular Malaysia. The results from our previ- ous work, where sufficient conditions on Bezier points have been derived, will be used in order to ensure that surfaces comprising quintic B´ezier triangular patches are always positive. The first and second derivatives at the data sites are calculated and modified (if necessary) to ensure that these conditions are satisfied. A number of examples are presented based on the average monthly rainfall data in a particular year at various locations in Peninsular Malaysia.