【作者】 谢倩茹；

【导师】 周明全；

【作者基本信息】 西北大学 ， 计算机软件与理论， 2003， 硕士

【摘要】 “数字地球”这一概念是信息技术在全球的应用发展过程中提出的，数字城市则是实施数字地球的关键节点。虚拟导航是虚拟现实技术在数字城市建设上的具体应用，是数字城市研究中的重要问题。虚拟导航拓展了数字城市的功能、提高了数字城市的实用性、丰富了数字城市的理论。 本文以“数字西大”为例，研究了数字城市中虚拟导航的实现方法。主要内容如下： 首先分析了系统中使用的基本理论与关键技术，主要包括空间数据库的建立与检索，虚拟现实技术，Java技术和ASP技术等。 然后结合西北大学的实际情况，完成了“数字西大”中的虚拟导航。解决的问题有：根据用户指定的任意两点位置检索空间数据库，完成自动游览；利用导航图跟踪和实时显示用户的当前位置；结合VRML与JAVA技术完成基于空间关系特征的查询和基于属性特征的查询。 最后设计了最优路径选取的算法。该算法以图的节点—弧段结构结合深度优先搜索实现了自动游览中最优路径的检索。根据系统对算法应用的情况，证明它的确提高了最优路径检索的速度和智能性。 数字城市中的虚拟导航增强了与用户的交互性，使地理实体的空间与非空间属性特征紧密结合，实现了三维场景与空间数据库的交互和空间查询，在数字城市的研究工作中有一定的理论意义和实用前景。对于本课题的研究可以为进一步开发基于网络的具有完全智能化的虚拟导航提供理论基础和技术支持，也为以后实现完整的数字城市积累经验。更多还原

【Abstract】 The concept of "Digital Earth" is put forward during the course of information technology’s development and application, Digital City is the crucial node that implements Digital Earth. Virtual Navigation is the specific application of virtual reality technology under Digital City construction, it is also a important problem in Digital City research. Virtual Navigation is to extend the function of Digital City, raise its practicality, rich its theories.This paper takes "Digital North West University" as example, to research the realization of Virtual navigation in Digital City. Major content is as follows: First, it has analyzed the corresponding basic theories and crucial technology of using, mainly include the establishment and retrieval of spatial database, technology of Virtual Reality, JAVA and ASP.Second, it has been completed Virtual Navigation in "Digital North West University" according to actual conditions of North West University. Retrieval spatial database by using the position of two point specified by user, complete the navigation automatically; Tracing and real-time display user current location depending on navigation map; Accomplish the query based on spatial relationship and property feature.Finally, devise the algorithm of optimum path. The algorithm makes use of the node-arc structure of graph and depth-first-search, have realized the retrieval of optimum path in virtual navigation. According to algorithm in system application, prove that it can raise intelligentance and the speed of optimum path retrieval. Virtual reality in Digital City strengthened the interaction with user, made the relation closer between geographic entity’s spatial and non-spatial property. It has great theory and practice significance in Digital City’s research. The resolvent to this problem supplied theories basis and technical support for the intellectualized virtual navigation based on the web, also accumulated experience for the realizing of 3D City.更多还原