【作者】 张晓莉；

【导师】 郭禾；

【作者基本信息】 大连理工大学 ， 计算机应用技术， 2006， 硕士

【摘要】 三维地理信息系统中视觉信息如何可视化输出一直都是该领域研究的重点，许多应用领域如虚拟现实、军事演习、网络游戏等都要求三维场景能够按照用户的要求动态显示。而随着计算机科学、计算机图形学以及现代数据理论的不断发展和创新，该问题也正吸引着越来越多的研究者们。但是，地形和地物是结构非常复杂的自然景象，其涉及到的空间几何数据、纹理数据等可以说是海量的。如何组织好这些数据，让其便于管理、查询、可视化输出，无疑是目前研究三维地理信息系统的关键。 解决三维GIS中的海量数据问题的主要着眼点在于如何减少可视化输出数据以及如何对海量数据进行简化。对于减少可视化输出数据方面，论文引入了建立场景索引机制，根据视点高度和位置确定可见区域范围和简化程度。对于空间位置数据主要采用R树和LOD原理相结合的方法，在大大减少三维顶点数量和三角形数量的同时，实现原始模型与简化模型的等价；对于实物纹理主要采取减少重复纹理数据的方法从而减少影像数据。数据量减少的同时，让用户感觉到随着视点的变化，景物简化程度随之变化，从而获得身临其境的效果。论文所研究的三维地理信息系统(GIS)中视觉信息的组织管理方法是建立在系统所采用的数据采集工具和处理过程的基础上的，其中包括道路信息校正、三维模型的建立和简化、纹理的组织和附着方式以及视觉效果的实现。根据具体过程特点和要求，论文讨论并介绍了相应的视觉信息组织模式，给出了三维GIS视觉信息的数据结构以及相应数据库的设计。更多还原

【Abstract】 How to realize the information visible output in the three-dimensional geographic information system is the important point in this domain research continuously. Many applications domains, like virtual reality, military exercises, network game and so on, all request the three-dimensional scene to dynamic demonstration accordance with the user demand. Along with the development and the innovation of the computer science, the computer graphics as well as the modern data theory, the question is also attracting more and more researchers. But the terrain and the surface features are extremely complex natural view, which involve the spatial geometry data, the texture data and so on. It goes without saying that the data is magnanimous. How organizes these data, makes it advantageous for management, query and visualization output, is the key of the three-dimensional geographic information system at the present research.To resolve the problems of massive data in 3D GIS is focused on how to reduce visible output data as well as how to simplify the massive data. In regard to reducing output data visualization, the thesis leads into establishment scene index mechanism, which helps to determine visible region and simplification degree according to height and location of view. For spatial position data, it mainly adopts the combination of methods with R-tree and LOD principle, which considerable reduces 3D point numbers and triangle numbers. Meanwhile, it realizes the original model and simplified model equal in value. For object texture, it mainly adopts the methods of reducing the redundant texture data so as to reduce the image data. According as reducing of the data quantity, it lets user feel that along with the viewpoint changing, the scene simplification degree is also changed, thus obtain the effect which experiences personally. The organizing management method of the three-dimensional geographic information system (GIS) in this thesis is based on the acquisition tool and the treatment processes of the data which in the system. It includes path information adjustment, the three-dimensional model establishment and simplification, the texture organization and attachment mode as well as the realization of visual effect. According to characteristic and request of the material process, it discusses and introduces the corresponding visual information organization pattern, and also provides data structure of the three-dimensional GIS visual information as well as the corresponding database design.更多还原