Visualization of Surface Data Using Rational Bicubic Spline

Scientific visualization is concerned with the presentation of interactive or animated digital images to users to understand data. The advantages of scientific visualization are: huge amount of data is converted into one picture, it correlates different quantities. One of the problems faced by scientific visualization community is visualization of positive data. Visualization of positive data in the view of positive surface is essential in visualizing the entities that cannot be negative e.g. amount of rainfall, volume, area, density, population etc. The problem of visualization of positive data has been considered by many authors [1-14]. But most of the authors considered the problem of visualization of positive scattered data [1,3,4,6,8,9,10,14] only a few have considered the problem of visualization of positive data arranged over rectangular grid [2,13]. A brief review is: Asim, Mustafa and Brodlie [1] visualized positive scattered data subject to positivity constraints using modified quadratic Shepard method. Brodlie, Mashwama and Butt [2] addressed the problem of visualization of positive data arranged over a rectangular mesh. Sufficient conditions for positivity are derived in terms of the first partial derivatives and mixed partial derivatives at the grid points. Brodlie, Asim and Unsworth [3] modified the quadratic Shepard method, which interpolates scattered data of any dimensionality to preserve positivity. Chan and Ong