Visualization of the sparsely scattered data on the surface of the sphere

Abstract

Graphics Visualization techniques are useful for analyzing a large amount of scientific data from experimentations, simulations or observations. Some of them can be applied to such real-valued functions as temperature, rain-fall or pressure defined over the surface of the earth that can be thought of as the surface of the sphere. In general such data as temperature or pressure are observed on the surface of the sphere, the location of which are scattered. The number of data points determines the costs. In this thesis a method is presented which visualizes the sparsely scattered data on the surface of the sphere. Triangulation is done as preliminary step for interpolation and visualization. Virtual data points are generated using triangle-based $c^1$ interpolation methods and used for visualization with real data. Contouring is used as a major visualization technique in this thesis. Also a technique is presented which renders a surface of the sphere with triangular decomposition. It is a variation of ray-tracing technique. It utilizes spatial coherences, which accelerate the process of finding the triangle containing the point to be displayed.