Three-Dimensional Digital Terrain Method Of Plate Tectonics

Virtual reality is developed to a certain level of computer technology and the product of the combination of thinking science. It has opened up a new way for human to know and reform the world. There is growing recognition of the important role of virtual reality technology for its ability to perform real-time three-demensional space, the operating environment and human-computer interactive immersive experience. Virtual reality technology will result in many traditional trades and industries revolutionary change.Three-dimensional terrain in virtual reality has extensive and important position. Large terrain modeling and rapid display is an important issue in the field of computer graphics. In recent years, smart phone represented by the mobile communication terminals developed very fast. Experts predict that in the near future, human society will enter the smart phone era. So in the current conditions, how to achieve large scale three-demensional terrain on the smart phone platform without strongly computing and storage to quickly show the areas of research has raised new challenges. In the face of gap between different hardware devices, researchers can not only focus on the detailed technical issues on one platform, but also pay attention to the macroscopic compatibility. By understanding the related technologies and ultimate platform for applications, people can better solve the problem. There are two major problems to quickly display large terrain. First it needs real-time processing of massive data; second it need provide adequate storage space for vast amounts of data. To the smartphone to do research on the three-dimensional digital terrain of plate tectonics has very important significance in reducing the amount of terrain data and space occupied.This paper introduces the construction method of three-dimensional terrain model including fractal terrain method, based on Perlin noise method and digital elevation model. The terrain generated by fractal terrain method or based on Perlin noise method is closer to the real natural terrain. However, it only uses in a smaller range because of computational complexity. DEM is mains to generate terrain because it is simple and can approximately reflect the natural terrain. So the DEM is the study in this paper.Compared with common PC computer, smart phone has small, portable benefits. Meanwhile, there are obvious shortcomings, such as computing and storage capacity is week, and need batteries to provide energy etc. Therefore, it must reduce the terrain data which need to be compute and store if the3D terrain will show on the smart phone. Thus, this paper presents a three-dimensional digital terrain method of plate tectonic to ruduce computational complexity and memory occupation.Because of large terrain based on DEM map, so the DEM map is huge. In this paper the huge DEM map will be devided into lots of sub-DEM maps. We create sub-terrain named Plate by sub-DEM map. Then it brings out narrow plate models and general plate models in this paper. Some or all the original terrain will be emerged by splicing through the plates. It is only need generate necessary plates when to show terrain according to the view. It cost little to deal with plates than terrain.Since the whole terrain is composed with plates, it need to be resolved problem of seamless display between the plates. It brings out9-grid model, plug and play model and embedded model in order to solve the problem about real-time accessing between plates. The terrain structure expression is defined so that the terrain can be abstract express by the expression. These three models can complete the task of terrain seamless display by experiment.When run the program, the smart phone CPU process more less data by the plates. In order to be able to show relatively smooth terrain, we must process terrain with LOD. Existing algorithms can accomplish this task very well such as ROAM and GeoMipMap and so on. However, these algorithms require the CPU to carry out LOD information continuously. It will have a greater power. The standby time will result in shorter and will cause inconvenience to the user’s work and life. Therefore, these algorithms are not suitable for direct use on mobile phone plateforms. We bring forword a completely static Grayscale model based on GeoMipMap model and give the relevant algorithms in this paper. The LOD information is stored in a GrayScale, and GrayScale of storage is optimized. GrayScale can further reduce the computationally intensive of mobile phone.