说明：  由于传统的基于文件管理的虚拟地形景观漫游系统在数据安全性、多用户操作、网络共享及数据动态更新等方面已不能满足数字城市或数字地球对海量空间数据一体化管理和在线实时应用的要求。介绍了基于Oracle 海量数据库的DEM动态可视化方法,包括金字塔结构的数据组织机制、采用数据分页的动态调度技术、与视点相关的地形简化和基于多线程的渐进描绘技术等。根据全国1∶25 万比例尺DEM数据库的应用实验证明该方法是可行的,并可以推广到影像以及其他模型数据的集成应用。
(Because of the traditional paper-based management of virtual terrain landscape roaming system in data security, multi-user, network and data-sharing, such as dynamic update has been unable to meet the number of cities or digital terrestrial integration of massive spatial data management and online real-time applications requirements. Based on Oracle database DEM Massive dynamic visualization methods, including the pyramid structure of the data organization mechanism, the use of the data page of the dynamic scheduling techniques, with the view-dependent terrain simplification and Multithread-based progressive portray technology. According to the National 1:25 million scale DEM database application experiment shows that this method is feasible and can be extended to imaging, as well as other model data integration applications.)