【作者】 李亚斌；

【导师】 刘丹；

【作者基本信息】 大连海事大学 ， 交通信息工程及控制， 2004， 硕士

【摘要】 三维地形在城市规划、工程勘查与设计、环境监测、灾害预测与预报、军事、游戏娱乐等诸多领域都有广泛的应用。如何实现基于海量数据的大规模三维地形的可视化更是目前研究的热点，本文就此问题做了如下研究： ◆对通用数字地形数据的几种数据模型的结构特点进行比较，提出基于栅格数据的动态分块及快速读取算法，实践证明该算法能够较好解决大规模三维地形的建模问题。 ◆针对海量数据的动态分块及快速读取算法，设计地形数据量自适应平衡子系统，该系统能够根据系统绘制三维地形场景的速度，自动调整系统处理的数据量，使不同性能的系统都能够平稳高效运行，增强系统的兼容性。 ◆通过纹理映射实现大规模三维地形场景的影像信息的叠加，对多种专题影像数据的叠加，是系统进行空间分析的基础。 ◆针对大规模地形细节表达能力较差的特点，引入基于图像绘制的细节表达方式，加强对地形地貌细节的表达。 ◆设计了大范围研究模式和快速漫游两种场景观察方式，使系统不仅能够较好表达大范围宏观场景，而且具有小区域详细观察、测量、计算分析的功能。 ◆引入了免费的开发工具包—FLTK，基于FLTK和OpenGL进行了原型系统的设计。由于FLTK和OpenGL都具有良好的可移植性，系统具有良好的可移植性和兼容性，为系统的跨平台及网络版本奠定了坚实基础。更多还原

【Abstract】 3D terrain has extensive application in many fields, such as city planning, engineering design, environment supervision, disaster forecast, military affairs, games and entertainment. At present, how to realize the visualization of large scale 3D terrain based on great data is the hot topic of research, the following studies have been done around the problem.The structural features of several data model of general digital terrain data have been compared, the dynamic partition and fast reading algorithm based on grid has been proposed, it has proved that this algorithm can solve the modeling problem of large scale 3D terrain.For the dynamic partition and fast reading algorithm of huge data, auto adaptation balance subsystem of terrain data has been designed. The system can adjust the amount of data processed by it automatically, make the system with various functions run steadily and affectively, enhance the compatible property of the system.The mergence of image information in large scale 3D terrain scene has been realized by texture mapping, the mergence of image information in many kinds spacial topics is the basis of special analysis, by the systemAiming at the bad details expressing ability of large scale terrain, the details expressing methods based on image rendering have been introduced, in order to reinforce the details expressing of the terrain.Two modes of observation have been designed: study mode of large terrain scenes and rapid exploring mode in small areas, so the system can not only render large scale scene of terrain, but also observe, measure, compute, analyzing in small areas.The toolkit (Fast Lightened Tool Kit, FLTK) that can be obtained freely has been introduced, and the system based on FLTK and OpenGL has been designed. For good properties in transplantation and compatibility, the system has excellent ability of running in many kinds of operation systems and upgrading to network version.更多还原