Papers by Keyword: Virtual Geographic Environment

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Authors: Jun Zhu, Yi Li, Ya Hu
Abstract: Dam-break flood affected by highly changing and complex environment, has some characteristics including the sudden of occurrence, the rapid of expansion and the urgency of respond. This paper focuses on how to develop a virtual geographic environment (VGE) system to study the dam-break flood routing and its impact. Unlike existing work, our methods pay attention to the multidimensional and dynamic analysis methods in virtual geographic environment, which make flood routing easily understood to public and officers. Moreover, some GIS spatial analysis and real-time interactive operation with the VGE will also be implemented to support the risk assessment of the dam-break. Finally, a prototype system is developed to construct a virtual geographic environment for impact analysis of dam-break flood routing and dynamic interaction. Experimental results prove that the scheme addressed in the paper is effective and feasible.
Authors: Bing Li Xu, Hui Lin, Wei Ning Cui, Ya Hu, Jun Zhu, Sammy Tang
Abstract: Air pollution dispersion is a typical geographic process. A reasonable way to simulate air pollution dispersion is to modeling the dispersion and presents the results in a geographically referenced virtual environment. In this research, we apply the concept of virtual geographic environments (VGE), which is coined in the community of geographic information science, to facilitate air pollution dispersion by integrating MM5 and VGE. Because MM5 is computation intensive, the CUGrid is used in this research to decrease the computation time. Our research focuses on three key points, which are the platform design, MM5 integration and computation on CUGrid, and geographical visualization of air pollution dispersion in VGE. Based on the prototype system, a case of simulating air pollution dispersion in Pearl River Delta is employed to validate and test the rationality of the methodology. As shown in this case study, VGE can provide a good way to visualize air pollution dispersion and the CUGrid can decrease model computation time significantly.
Authors: Bing Chuan Jiang, Xiong You, Qing Xia, Wei Zhang
Abstract: The expression of virtual geographic environment is based on the surface modeling, such as three-dimensional terrain modeling and rendering most of which are based on the polygon grid and 2D textured. In the expression of extreme terrain, such as caves, cliffs, canyons it seems powerless. However, the voxel-based terrain modeling has been more useful than polygon modeling expression in the field of real-time terrain deformation, extreme terrain simulation and geographic process expression. Furthermore, virtual geographic environment based on the traditional surface model is difficult to realistically simulate the real world which is volumetric. This paper analyzes the trends of the geographical environment representation, and discusses the typical voxel-based applications in natural phenomena simulation, terrain modeling and spatial process analysis. It provides the references for the integrative representation of the unified voxel and surface model, and for the construction of virtual geographic environment unified platform.
Authors: Hong Wei Wang, Jun Xie, Xiao Juan Wang, He Nan Wu
Abstract: Spatial Cognition ability reflects the level of real-time spatial orientation and situation awareness of pilots during flight, which is one of important factors that determines the level of flight ability. This paper explains the Spatial Cognition principle and training methods, and researches training methods of Spatial Cognition based on the 3D virtual geographic environment of Digital Earth, striving to break through bottleneck of the traditional Spatial Cognition training methods.
Authors: Bing Chuan Jiang, Qing Xia, Xiong You
Abstract: Due to the nature of the two-dimensional features of traditional “surface model” method for building the virtual geo-graphic environment, it is difficult to realistically simulate the real world of three-dimensional body. In this paper, fully understanding the basic concepts of voxels and features, based on the analysis of octree voxel model and rendering, we focus on the voxels in a virtual three-dimensional topography of the geographical environment for the simulation of natural phenomena, the expression of geographical process, spatial analysis and its research in the application. Also we discuss the virtual geographic environment which is based on “volumetric model”.
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