【作者】 付哲；

【导师】 周云轩；

【作者基本信息】 吉林大学 ， 地球探测与信息技术， 2006， 博士

【摘要】 本文针对虚拟GIS的最基本技术问题之一——虚拟GIS数据模型展开讨论,在分析前人相关研究基础上,剖析虚拟GIS数据特点,使用基于特征的建模技术对虚拟GIS中的数据模型问题进行了一系列初步研究,并取得一定进展。文章首先对虚拟现实和GIS系统集成理论进行了详细的研究,然后根据当前虚拟GIS数据模型的研究进展,使用基于特征的建模技术建立了基于特征的虚拟GIS概念模型。在基于特征的虚拟GIS概念模型基础上,应用面向对象的思想,设计了基于特征的面向对象虚拟GIS数据模型(FOVGISDM),并系统分析了该模型的结构、各成分定义以及相互间的关系等问题。为实现FOVGISDM的逻辑表达,文章利用Oracle对象-关系型数据库管理模式设计并实现了基于特征的面向对象虚拟GIS数据库管理,同时,系统阐述了基于特征的虚拟GIS数据库设计基本步骤,依次详细介绍了各个设计阶段应注意的具体内容。最后,文章在基于特征的面向对象虚拟GIS数据库基础上,整合虚拟视景仿真和GIS技术,构建了基于Client/Server层次结构的分布式虚拟GIS原型系统。另外,本文还详细叙述了原型系统特征建模过程、步骤以及关键技术。更多还原

【Abstract】 Virtual reality (VR) construct multi-dimensional spatial informationenvironment which have the ability of perfect interaction between man andcomputer, and Geographic information system (GIS) do well in the spatial geographicfeature analysis and processing. Therefore, integrating VR and GIS becomes essential inearth science study and practice. Virtual GIS becomes one of the major areas of GISwhich is a trend of information visualization virtual representation. The systemintegration of VR and GIS is being in the period from operational level to functional levelnowadays. Compared with rudimentary level and operational level, the functional levelmainly obtains data sharing by database mode, which have the powerful spatial-temporalefficiency. Therefore, a new data model must be designed by system developer for storingGIS data、multimedia data or other kind of data, by which user can get spatial attributesand non-spatial attributes of the “real” world in the most natural way.On the basis of data models that are applied in the fields of CAD, virtual reality andsimulations, a new feature-based object-oriented data model (FOVGISDM) for virtualGIS is initiated, in which feature-based modeling techniques and object-orientedapproaches are applied. The main contents of this dissertation are as follow:(1)First of all, the research background of virtual GIS is reviewed. We mainlyinvestigate the development trend of virtual reality and multi-dimensional GIStechniques. In terms of the research progress of virtual GIS, the purpose and significanceof the research is stated.(2)With reference to the development trend of virtual GIS, the integration principlesof VR and GIS are discussed in detail. Four VR and GIS integration methods arelisted on the basis of integration principles. Their system structures and characteristics areelaborated, respectively. The four stages of the integration are illustrated. The currentstatus of the integration and its development trend are analyzed. Meanwhile the keyproblems exist in the VR and GIS integration is explored, which includes data, virtualscenery, web VRGIS, and so on. Suggestions and approaches are presented to providesome possible solutions in resolving these key problems.(3)Through a thorough analysis of the current data models used by Virtual GIS, thefeature-based virtual GIS conceptual model framework is established by thefeature-based modeling technique for the most level abstract scheme of virtualspatial-temporal information representation. The dissertation not only defines the conceptof feature in virtual GIS, but also discusses the way of organizing virtual spatial-temporalinformation by the feature. The conceptual model takes the spatial characteristic ofgeographic entity into count;moreover, considers the understanding of geographicobject’s semantic information in the process of interaction between man and virtualgeographic environment. At the same time, the conceptual model emphasizes theintegrality of feature, unifies the attribute、relationship、behavior and scenario propertiesof feature into the basic element unit for managing and operating the data of virtual GISdata model efficiently.(4)Based the conceptual model, using object-oriented methodology, thefeature-based object-oriented virtual GIS data model (FOVGISDM) is constructed. Thedissertation analysis the structure of FOVGISDM, including to the description anddefinition of feature object、feature semantic object、feature geometry object. Using theUML modeling tool, the geographic feature class diagrams are constructed. We also givean example of building feature object for explanation. Furthermore, the featurerelationship of FOVGISDM is analyzed systemically, especially the geometryrelationship and semantic relationship between feature objects.(5)The feature-based object-oriented virtual GIS database is be designed andrealized for virtual GIS data management with Oracle ORDB management model. Thedissertation introduces the basic steps of database design and the specific contents of eachdesign process in detail. After FOVGISDM is expressed as seven kinds of featureelement explicitly and integrally in the logical structure design step, the structure of tablestorage is be introduced in the physical structure design step. Each object data typeinvolved in the virtual GIS database is also stated in detail. Furthermore, we take examplefor the implementation of city virtual scene database.(6)Making use of the new data model, a Client/Server structured distributed virtualGIS prototype system is implemented. This system manages the modeling data by theserver, and supports visiting a vast amount of data with high speed and gettingmulti-resolution or semantic information easily. Using the designed interface betweenprototype system and database, the client read or writes these scene data swimmingly.With Vega API and VC++ as exploiting tools, the experimental software UI platform ofvirtual GIS prototype system is developed. It realize the loading of virtual scene model 、parts of spatial query functions and other real-time simulation and virtual realityapplications, such as drive、fly motion model. Furthermore, the feature modeling steps ofprototype system and key techniques is stated in detail.更多还原