【作者】 左小清；

【导师】 李清泉；

【作者基本信息】 武汉大学 ， 摄影测量与遥感， 2004， 博士

【摘要】 交通是人们生活的重要组成部分,是地理信息系统(GIS)的一个重要应用领域。表达日趋复杂的交通现象,需要有三维GIS理论的支持,但随之产生一系列的问题需要解决。论文就如何在二维GIS中表达复杂的道路交通现象展开研究,其核心的研究内容是探讨描述交通网络中的复杂三维特征及其网络拓扑关系的数据模型,道路网三维数据(包括拓扑数据)的组织与管理,不规则道路网与地形集成模型的多分辨率动态简化算法,基于道路网三维数据的空间索引方法等。论文主要研究工作如下: 1.首先对论文相关工作的研究进展进行了回顾,重点介绍了GIS-T(Geographic Information System for Transportation)的线性数据模型、三维数据模型、三维数据的管理与三维可视化技术的研究现状; 2.线性参照系统(LRS)与动态分段是GIS-T的主要特征和关键技术。论文首先介绍了线性参照系统与动态分段技术,重点讨论了三维系统中线性参照基准的建立方法,线性参照坐标与空间坐标之间的转换方法,并对动态分段进行了扩展,使其应用于三维几何数据的动态分段组织,为三维GIS与GIS-T的结合创造了条件; 3.对道路交通网的几何、拓扑建模要素进行了详细讨论,论述了顾及路网的地形模型的表达方法。在此基础上,将线性参照系统和动态分段技术集成到模型中,采用面向对象的方法,发展了一个面向交通应用的三维数据GIS模型,为三维GIS与GIS-T的结合提供了理论基础; 4.三维数据的管理是三维GIS的重要内容。当不规则的道路网与地形模型集成后,使得模型难以进行规则分块,这样,道路模型与地形模型的数据管理变得复杂。针对道路模型数据、附属设施数据及地形模型数据的管理进行了深入讨论。首先对不规则三角网的存储结构进行了回顾,针对论文提出的交通网络三维数据模型,改进了点、边、三角形结构。讨论了三角网数据的文件和数据库管理方式,并设计了不规则三角网的数据库存储结构。讨论了道路多重属性数据的管理,设计了道路三维几何数据的结构及其数据库存储结构,进而对三维模型的数据库管理进行了讨论,对于移动目标,提出一种动态分段的数据结构来存储其历史轨迹数据,大大减少了数据存储空间。对已有道路网拓扑数据的表达方式进行了回顾,设计了建立在三维几何网络基础上的拓扑数据结构及数据库物理实现结构; 5.介绍了地形层次细节(LOD)模型的相关工作,着重对渐进格网(PM)算法进行了分析,并指出了PM算法应用到道路网模型存在的一些问题,并根据地形和道路集成的模型的特点,提出一种“回”结构的视相关动态LOD模型,该算法以视点为中心,按距离层层嵌套设置分辨率等级和控制误差,并通过控制顶点树深度的方法较好的解决了边折叠算法中模型难以恢复的问题,算法避免了在模型简化过程中的交义、重叠和细长的三角形出现。并从算法的基本原理、算法实现的数据结构到模型的建立过程进行了详细论述,包括模型的动态简化利细化过程,最后根据提出的算法进行了相关实验;更多还原

【Abstract】 Transportation, a vital component in people’s daily life, is a significant applied field to GIS. In general, more complicated transportation phenomenon needs support of 3D GIS theory, but at the same time a series of problems will emerge which need be solved. The dissertation will focus on the problems created while 3D GIS describing complex road transportation phenomenon. The key contents of the dissertation is to develop a 3D data model, which can describe complex transportation features, organization and management of 3D road data, including topology relation data about road network, multi-resolution dynamic simplification algorithm of irregular road network and terrain integrated model and spatial index method based on road network 3D data, etc. The main research work of this dissertation is as follows:1. Research progress of relevant work is reviewed. The dissertation introduces present research situation about linear data model of GIS-T, 3D data model, management of 3D data and 3D visualization technology.2. LRS and dynamic segmentation is the characteristic and leading technology of GIS-T. Therefore, after discussing LRS and dynamic segmentation, the establishment method of linear reference datum and transformation method between linear coordinate and spatial coordinate are talked over in the dissertation. To apply it to dynamic segment of 3D Geometry data, the dissertation also extends dynamic segmentation model to organization for 3D Geometry data, which makes it possible to the combination of 3D GIS and GIS-T.3. Basic modeling elements on topology and Geometry of road network are discussed and expression approach of terrain model considered road network is mentioned. In the basis of this, this paper integrates LRS and dynamic segment to the model. Using the method of object-oriented, 3D GIS model applied to transportation is developed, which can provide theory basis for the combination of 3D-GIS and GIS-T.4. The management on 3D-data is an important content of 3D GIS. After irregular road network is integrated to terrain model, it is difficult to divide the model into regular patches. Accordingly, data management on road model and terrain model becomes more sophisticated. The managements about road TIN data, affiliated facilities data and terrain model data are talked over in the dissertation. Aimed at 3D data model of transportation network mentioned, the dissertation firstly reviews the storage structure of triangle network and improves the structure of edge, vertex and triangle. Next, base on file and database management approach for triangle data on are discussed, and database storage structure of irregular triangle is designed. The dissertation also discusses management of road multi-overlap attribute data, designs the structure of 3D road Geometry data and database storage structure and then talks over database management on 3D model. To the moving objects, a type of data structure with dynamic segment is proposed to store the data on history tracks, which can save on data storage spacegreatly. Eventually, the dissertation recalls present expression approach about road network topology data and designs the structure on topology data based on 3D Geometry network and physical realizing structure on database.5. The relevant work on LOD model is introduced. By analyzing progressive mesh (PM) algorithm, the dissertation points out some problems when employed to road network model. In terms of characteristic of mesh model integrated by terrain and road model, the dissertation proposes LOD algorithm based on multi-resolution of irregular triangle network with the structure in the shape of "IhJ". The algorithm, with the viewpoint as its central, designs resolution levels and controlling error orderly according to the distance. The algorithm solves the problem on which the model is difficult to recover during edge collapse by controlling the depth of vertex tree, and avoids the emerging of intersecting, overlapping or slender triangle base on relative experiment results.6. Irregular road network 3D data advances a new demand to traditional method of multi-dimensional index. The dissertation firstly analyses R-tree index and procedure of establishment and then raises hybrid index mechanism combined integrated connection with dynamic segmentation according to the characteristic of road network inter-connected. Next, the principle, establishment procedure and query steps about connective index are elaborated in the dissertation and hybrid index mechanism are compared with R-tree index in space and query efficiency base on experiments. Finally, the dissertation narrates the dynamic loading process of 3D data on road network.7. The exploitation of experiment system. Based on data model and algorithm proposed this paper, with VC++ and OpenGL as exploiting tools, the experimental software system, having the functions on 3D model of establishing, editing, visualization and transportation analysis, is developed. Base on the experimental system, we can realize the model and algorithm mentioned in this paper.Principal contributions include:1. 2D LRS and dynamic segmentation technology are extended to come true dynamic segmentation of Geometry data on road network, which can provide a better condition for the combination of 3D-GIS and GIS-T.2. A 3D data model, expressing complicated road transportation phenomenon and considering visualization and spatial operation, is developed, which furnishes the theory basis for 3D GIS and GIS-T. 3D data model not only enriches the contents about digital city but also has great significance in promoting the application of GIS in transportation field.3. Aimed at 3D data model of transportation network, this paper improves structure of vertex, edge and triangle. After that, the data structure of irregular triangle network, 3D road Geometry and attribute data based on dynamic segmentation organization is designed. To the moving objects, a type of data structure with dynamic segment is proposed to store the data on history track, which can reduce the amount of data greatly. The dissertation advances topology data based on 3D Geometry network and physical realizing structure on database.4. After the integration of terrain and road model, the mesh is usually irregular. Focus on this characteristic of the integration mesh, the paper proposes LOD algorithm based on multi-resolution of irregular triangle network with the structure in the shape of "0". The algorithm, with the viewpoint as its central, design resolution levels and controlling error orderly according to the distance. The algorithm solves the problem on which the model is difficult to recover during edge collapse by controlling the depth of vertex tree. The algorithm avoids the emerging of intersecting, overlapping or slender triangle base on relative experiment results.5. 3D data on irregular road network brings forward a new demand to traditional method of multi-dimensional index. The paper put up a spatial index method based on interlinked topology, which can build up index for the central line of road. It is well known that the data is along the road in a linear way and the roads connect to each other. According to the above characteristic, a hybrid indexing mechanism combine connecting with dynamic segment is proposed in this paper, which can realize the query process in two steps. The first step is to search rough by connecting index. Based on the results of the first step, the second step can finish the exact query process satisfactorily using dynamic segmentation index. This index mechanism with high query speed guarantees speed of loading data dynamically, and fulfills the demand of visualization of road network.更多还原