The Research And Application Of The Weather Phenomena Simulation In 3D GIS

Three-dimensional Geographic Information System (3D GIS) has been an important research focus during the past two decades. 3D visualization is an important research subject in 3D GIS. At present, some research has been developed in the research of 3D visualization, but some of them, such as real-time rendering of large-scale scene and visually-realistic simulation of scene, need to make a detailed investigation and systematic research.At present, the techniques of simulating weather phenomena is mainly physically-based, then appropriately simplify mathematics models. If directly applying these techniques on 3D GIS, with the condition of the current hardware performance, the requirement of the application is impossible to be satisfied. So, the simulation in this paper is directed by actual application, to make sure realistic-looking animation and real-time rendering effects.This paper is based on the actual development of the "3D Weather Demo System" by the author, makes visualization development and research mainly from several weather phenomena. On the research of sky background, this paper advances characteristic functions based on the analysis of the variations in sky color and implements the color computation of different vertex on the sky dome. On the research of clouds, this paper, focused on the real-time rendering and realistic-looking animation of static particle clouds, puts forwards the spatial index technology of clouds, and combines with the simplified theory of atmosphere scattering and the rendering technique of 3D spatial objects to increase the frame rate. On the research of rain and snow, this paper, based on the advanced particle system, this paper analyzes the characteristics of raindrop and snowflake respectively and simulates the phenomena of rainfall and snowfall.In conclusion, based on the reference to and the combination with recent research fruits, this paper advances some methods to simulate several weather phenomena, such as sky, atmosphere, clouds, rain, snow, and so on. Accordingly, this paper completes realistic-looking animation and real-time rendering effects in 3D GIS. These methods that the author proposes in this paper have been successfully embedded in the "3D Weather Demo System", and the result is satisfying.