【作者】 刘玲；

【导师】 周云轩；

【作者基本信息】 吉林大学 ， 固体地球物理， 2004， 硕士

【摘要】 本学位论文是在教育部《高等学校优秀青年教师教学科研奖励计划》资助的课题“基于地理信息系统的综合地学信息集成理论、方法及应用”的支持下完成的。本论文的目的是在虚拟地理环境的基础上实现基于GIS的信息管理、查询、分析功能，构建一个虚拟地理环境信息系统。主要阐述了如何基于虚拟现实技术理论在空间数据库支持下构建虚拟地理环境，并在三维地理数据上叠加矢量、栅格数据，实现空间到属性和属性到实体的一对一和一对多的查询；最后成功的将此信息系统运用于吉林西部的生态环境研究中，对整个吉林西部的土地利用发展变化进行动态监测以及预测分析。论文在充分分析了GIS的发展现状、发展趋势后，得出现今GIS的一个主要的缺点，就是可视化能力十分不足，这严重影响了GIS的普及与应用。在对虚拟现实技术进行研究后，提出把虚拟现实技术应用到GIS中的设想。虚拟现实（Virtual Reality）技术是20世纪末发展起来的以计算机技术为核心，及多学科高新技术为一体的综合集成技术。虚拟现实综合利用了计算机的立体视觉、触觉反馈、虚拟立体声等技术，高度逼真地模拟人在自然环境中的视、听、动等行为的人工模拟环境。以虚拟现实技术作GIS系统的显示界面，GIS向虚拟现实提供数据支持。这样，两方面的优点得以整合。一方面，GIS的可视化能力不足，无法让所有用户，特别是对地图一窍不通者（overwhelmingly map illiterate）非常容易地理解GIS的结果，并做出正确的判断。虚拟现实技术可以弥补这一点，可以作为GIS与用户的中介或桥梁，它实现了对地理信息数据淋漓尽致的表达，使用户沉浸到虚拟的地理环境之中，从多角度、多层次，实时地去感受和理解我们对地理环境的分析和模拟。另一方面，虚拟现实技术需要一个基础的数据平台，以便可以对数据进行收集、管理、储存、查询、分析，而这正是GIS所具备的基本功能。本文对虚拟现实技术与GIS的信息管理功能的结合进行了初步研究探讨。首先对虚拟地理环境系统的模块框架结构进行了功能分析和设计。在确定虚拟地理环境信息系统的基本功能的基础上将该系统分为数据文件管理资系统，虚拟环境可视化子系统，空间分析查询子系统，以及应用专题子系统。 <WP=86>虚拟地理环境是构建在当今计算机图形显示设备性能的改进，高性能的图形工作站的出现，高度真实感图形的生成算法的不断涌现和完善的基础之上的，它实质上是针对地形地貌的一种数字建模过程，这种建模的结果通常是数字高程模型（DEM）。本文系统的论述了DEM的概念、表面建模技术以及内插算法，并结合当前GIS三维数据模型的研究，构建了一个多源信息一体化模型，运用交互式可视化语言IDL实现了虚拟地理环境的可视化和实时动态显示，同时在虚拟地理环境中实现了GIS多维数据的叠加以及空间查询分析功能。系统开发平台的选择是在综合比较了多种常用虚拟现实开发平台的结果后确定的。IDL具有丰富的功能函数和强大的海量数据处理能力，运用面向对象技术进行各功能模块的编程处理。系统在开发过程运用了大量的技术，有计算机真实感图形学技术、科学可视化技术等。作为虚拟现实与GIS的结合，本文重点研究了GIS的多种数据如二维矢量、三维地物数据等在虚拟环境中实现。本系统应用于吉林西部生态环境研究中，真实生动的将吉林西部各县的地理环境得以再现，用户可以在虚拟环境中实现一系列空间操作功能，包括放大、缩小、平移、转动、飞行漫游、飞行路径设定、回放等相关功能。土地利用作为整个生态环境变化的重要因素是自然因子和人文因子共同作用的结果体现，也是生态环境各子系统相互作用的最终结果和核心。本系统将吉林西部土地利用的检测结果以及相关的预测分析结果以矢量或栅格数据格式叠加在虚拟地理环境中进行动态显示，并实现了各种空间信息及其属性信息的查询，从时间维和空间维来分析土地利用的动态变迁。为生态环境的治理改善提供参考。更多还原

【Abstract】 The work presents a thorough discussion on the building a virtual geo-environmental information system (VRGIS) and the implementation of the preliminary functions of information management, query and analysis based on virtual geographical environments. And the preliminary functional VRGIS is applied to western Jilin Province for the purpose of evaluation and monitoring the land-use and land cover change.A weak point of any given GIS at the present is that it does not have adequate ability in visualization. With the development of the Virtual Reality (VR) technology, a new method was brought forward which is to apply the VR technology to GIS. Virtual Reality is a new technique developed on the end of 20th century. It has been defined as a way for humans to visualize and manipulate extremely complex data, and interact with computers. Many people find it difficult to visualize the data represented by a GIS. However, VR promises an environment, which fully engages all the users’ senses and provides full interactivity in real time. Virtual environments provide greater immersion into the world or environment of scientific data, thereby enhancing the researcher’s perception of its features and forms. It is our attempt to integrate VR and GIS technologies to discover more information out of available data. GIS manages its huge, complex terrain and GIS data sets at real time rates in an efficient manner by using hierarchical spatial data structures. Virtual Reality adds an important freedom for the user to visualize and interpret spatial data more effectively. The functional module and framework of the system is analyzed and designed. The system is divided as data management subsystem, virtual geo-environments visualization subsystem, and spatial query & analysis subsystem, and special application subsystem. Virtual geo-environments building is based on the development of computer technology, the appearance of high-powered graph workstation and the creation of real sensing graph algorithmic. The progress of building virtual <WP=88>geo-environments is a digital-modeling to terrain and relief, the result is Digital Elevation Model (DEM).This paper introduces a multi-source information model after studying the basic theory and key technology of DEM and the present study of GIS 3D model. The system was developed with the Interactive Data Language (IDL), which is the fourth generation programming language. Because it is easy to learn and has abundant functions and can produce satisfactory result, IDL is the ideal software to develop Virtual Reality module, which is object-oriented. The development of the system makes use of many computer techniques including real sense computer graphic technique, scientific visualization technique and so on. It is important to study how to present the special GIS data in the virtual geo-environments.The system has been applied to the western Jilin Province. The system establishes the virtual environments of every county in the study area. The environments are simulations of the real world supported by a GIS. And users can operate in the environments, such as walking in the environments at will. The land-use is one of the most important factors causing the entironmental changes, which is the interactional result by all kinds of subsystems of the entironment. The preliminary VRGIS system developed in this work can be used to analyze the land use changes and to provide a useful aid for the protection of the environmental.更多还原