A design of three-dimensional spatial data model and its data structure in geological exploration engineering

The key to develop 3-D GISs is the study on 3-D data model and data structure. Some of the data models and data structures have been presented by scholars. Because of the complexity of 3-D spatial phenomenon, there are no perfect data structures that can describe all spatial entities. Every data structure has its own advantages and disadvantages. It is difficult to design a single data structure to meet different needs. The important subject in the 3-D data models is developing a data model that has integrated vector and raster data structures. A special 3-D spatial data model based on distributing features of spatial entities should be designed. We took the geological exploration engineering as the research background and designed an integrated data model whose data structures integrats vector and raster data by adopting object-oriented technique. Research achievements are presented in this paper.     

Towards an integral strategy for modelling uncertain geospatial data

This paper endeavours to put the discussion on errors and uncertainties in geographical information systems (GISs) in a more systematic way by examining the strength and weakness of discrete objects and continous fields, the two distinct schools of spatial data modelling. In doing so, it argues that neither discrete objects nor continous fields alone provide objective and complete representations of highly complex geographical phenomena, though there are good reasons for asserting that continuous fields are better suited to modelling spatial dependence, heterogeneity and fuzzines significant in geographical reality than discrete objects. Thus, there seems to be merit in adopting an integrated model incorporating analytical capabilities of fields and generalization functions of objects, for which extended TIN (triangulated irregular network) models along with their duals (Voronoi diagrams) provide a pragmatical solution.     

Towards an integral strategy for modelling uncertain geospatial data

This paper endeavours to put the discussion on errors and uncertainties in geographical information systems (GISs) in a more systematic way by examining the strength and weakness of discrete objects and continuous fields, the two distinct schools of spatial data modelling. In doing so, it argues that neither discrete objects nor continuous fields alone provide objective and complete representations of highly complex geographical phenomena, though there are good reasons for asserting that continuous fields are better suited to modelling spatial dependence, heterogeneity and fuzziness significant in geographical reality than discrete objects. Thus, there seems to be merit in adopting an integrated model incorporating analytical capabilities of fields and generalization functions of objects, for which extended TIN(triangulated irregular network) models along with their duals (Voronoi diagrams) provide a pragmatical solution.     

A design of three-dimensional spatial data model and its data structure in geological exploration engineering

The key to develop 3-D GISs is the study on 3-D data model and data structure. Some of the data models and data structures have been presented by scholars. Because of the complexity of 3-D spatial phenomenon, there are no perfect data structures that can describe all spatial entities. Every data structure has its own advantages and disadvantages. It is difficult to design a single data structure to meet different needs. The important subject in the3-D data models is developing a data model that has integrated vector and raster data structures. A special 3-D spatial data model based on distributing features of spatial entities should be designed. We took the geological exploration engineering as the research background and designed an integrated data model whose data structures integrats vector and raster data byadopting object-oriented technique. Research achievements are presented in this paper.     

GIS中三维空间数据模型的集成与应用

针对三维地理信息系统中的三维空间数据模型,结合城市规划工作,分析讨论了三维数据模型集成的必要性以及TIN与CSG、八叉树与TEN、矢量与栅格等混合数据模型实现的方法和思路,提出了在城市规划应用中模型集成的适用类型及有关要求.     

Component-based topological data model for three-dimensional geology modeling

On the study of the basic characteristics of geological objects and the special requirement for computing 3D geological model, this paper gives an object-oriented 3D topologic data model. In this model, the geological objects are divided into four object classes: point, line, area and volume. The volume class is further divided into four subclasses: the composite volume, the complex volume, the simple volume and the component. Twelve kinds of topological relations and the related data structures are designed for the geological objects.     

Component-based topological data model for three-dimensional geology modeling

On the study of the basic characteristics of geological objects and the special requirement for computing 3D geological model, this paper gives an object-oriented 3D topologic data model. In this model, the geological objects are divided into four object classes: point, line, area and volume. The volume class is further divided into four subclasses., the composite volume, the complex volume, the simple volume and the component. Twelve kinds of topological relations and the related data structures are designed for the geological objects.     

Quantitative data graphics in 3D desktop-based virtual environments – an evaluation

3D desktop-based virtual environments provide a means for displaying quantitative data in context. Data that are inherently spatial in three dimensions may benefit from visual exploration and analysis in relation to the environment in which they were collected and to which they relate. We empirically evaluate how effectively and efficiently such data can be visually analyzed in relation to location and landform in 3D versus 2D visualizations. In two experiments, participants performed visual analysis tasks in 2D and 3D visualizations and reported insights and their confidence in them. The results showed only small differences between the 2D and 3D visualizations in the performance measures that we evaluated: task completion time, confidence, complexity, and insight plausibility. However, we found differences for different datasets and settings suggesting that 3D visualizations or 2D representations, respectively, may be more or less useful for particular datasets and contexts.     

三维城市模型的研究与实践(英文)

The way we interact with spatial data has been changed from 2D map to 3D Virtual Geographic Environment (VGE). Three-dimensional representations of geographic information on a computer are known as VGE, and in particular 3D city models provide an efficient way to integrate massive, heterogenous geospatial information and georeferenced information in urban areas. 3D city modeling (3DCM) is an active research and practice topic in distinct application areas. This paper introduces different modeling paradigms employed in 3D GIS, virtual environment, and AEC/FM. Up-to-date 3DCM technologies are evolving into a data integration and collaborative approach to represent the full spatial coverage of a city, to model both aboveground and underground, outdoor and indoor environments including man-made objects and natural features with 3D geometry, appearance, topology and semantics. Supported by the National Natural Science Foundation of China ( No. 40871212, No. 40671158), the Leading Academic Discipline Project of Shanghai Educational Committee( No.J50104).     

面向规划的三维地理实体数据模型与生产技术

三维地理信息为新一轮的国土空间规划提供了新动能,三维空间数据模型是三维地理信息发展和应用的基础和关键,面向实体的三维模型是三维空间数据模型的一种重要表达方式。本文提出了一种面向规划的三维地理实体数据模型,并以浙江省嘉善县的生产应用实践为例,详细阐述了实体生产的关键技术和应用效果,对三维地理信息更好地服务于国土空间规划、提升空间治理能力、实现治理体系现代化具有重要意义。     

基于SOA的空间数据管理研究

为了将物理上分散在各地的空间数据有机整合,本文提出了基于SOA的空间数据管理网格模型,该模型由局域网格和广义网格组成。空间数据管理网格将物理分布的空间数据在逻辑上组成一个超大虚拟的空间数据库,实现全国乃至全球的海量空间数据的管理。为了验证空间数据管理网格的先进性、可行性,笔者采用JA-VA3D基于空间数据管理网格开发了海量地形网络三维浏览器。     

On strategies and automation in upgrading 2D to 3D landscape representations

3D scenes within all media indicate a societal preference shift toward 3D presentations. In spite of wide data availability and successful standardization efforts in 3D modeling, it is not a standard practice to offer large-scale topographic references to the end user in the form of 3D models. This motivates to propose automated strategies for the generation of closed 3D representations of a complete urban landscape, which at the same time account for capabilities of consumer-class devices. The campus of Dresden University of Technology served as a test case. The final appearance of the 3D model will be steered directly by the original geographic information system (GIS) data source. Such a “schematic model” displays source classes and attributes by nonphotorealistic rendering. A tested generic workflow can be presented, which programmatically integrates attributed 2D GIS entities and digital elevation model data, checks for compliancy with consistency rules and generates a slim geometric model. Only detailed GIS references can be considered to allow close-range visualization as needed in virtual walks. In delegating the geometric processing to automated workflows, playing room is gained for as well innovative as expressive texturing and, thus, design of the final 3D model.     

QTPV Data Model and Algorithm and Its Application to Geological Exploration Engineering

3D spatial data model and simulating are the core of 3D GIS can be adopted in different domains. A data model based on Quasi Tri-Prism Volume (QTPV) has been proposed. QTPV definition and its special cases have been discussed. Using QTPV and its special cases, irregular natural geological bodies and regular subsurface engineering can be described efficiently. The proposed model is composed of five primitives and six objects. Data structures and topological relationship of the fives primitives and three objects describing stratigraphy are designed in detail Some schemes are designed for the QTPV modelling of stratigraphy and subsurface engineering according to modelling data. The model manipulation method of QTPV cutting by an arbitrary plane is discussed. Using VC 6.0 programming language integrated with SQL database and OpenGL graphic library under windows environment, a system prototype 3DGeoMV has been developed. The experiment result shows that the QTPV model is feasible and efficient in modelling subsurface engineering.     

QTPV data model and algorithm and its application to geological exploration engineering

3D spatial data model and simulating are the core of 3D GIS can be adopted in different domains. A data model based on Quasi Tri-Prism Volume (QTPV) has been proposed. QTPV definition and its special cases have been discussed. Using QTPV and its special cases, irregular natural geological bodies and regular subsurface engineering can be described efficiently. The proposed model is composed of five primitives and six objects. Data structures and topological relationship of the fives primitives and three objects describing stratigraphy are designed in detail. Some schemes are designed for the QTPV modelling of stratigraphy and subsurface engineering according to modelling data. The model manipulation method of QTPV cutting by an arbitrary plane is discussed. Using VC++ 6.0 programming language integrated with SQL database and OpenGL graphic library under windows environment, a system prototype 3DGeoMV has been developed. The experiment result shows that the QTPV model is feasible and efficient in modelling subsurface engineering.     

Fields as a framework for integrating GIS and environmental process models. Part 1: Representing spatial continuity

Linking a GIS to a spatially distributed, physically-based environmental model offers many advantages. However, the implementation of such linkages is generally problematic. Many problems arise because the relationship between the reality being represented by the mathematical model and the data model used to organize the spatial data in the GIS has not been rigorously defined. In particular, while many environmental models are based on theories that assume continuity and incorporate physical fields as independent variables, current GISs can only represent continuous phenomena in a variety of discrete data models. This paper outlines a strategy in which field variables are used to enable modellers to work directly with the spatial data as spatially continuous phenomena. This allows the manner in which the spatial data has been discretized and the ways in which it can be manipulated to be treated independently from the conceptual modelling of physical processes. Modellers can express their spatial data needs as representations of reality, rather than as elements of a GIS database, and a GIS-independent language for model development may result. By providing a formal linkage between the various models of spatial phenomena, a mechanism is created for the explicit expression of transformation rules between the different spatial data models stored and manipulated by a GIS.     

海洋地理环境矢量数据的融合研究

海洋地理环境矢量数据融合涉及对象繁杂,实现存在较大的困难。本文从二维矢量数据融合和三维地形数据融合出发,研究了海洋地理环境矢量数据融合的方法。     

城市三维GIS中的海量数据组织方法

针对城市三维GIS中的海量数据组织需求,本文设计并实现了基于关系数据库的三维模型数据库,主要特点是支持地形数据、三维模型几何与纹理数据的一体化存储和属性的自定义动态管理。结合城市三维GIS中的海量数据访问和管理需求,从空间索引、纹理缓存、属性存取、数据加密、数据更新等方面介绍了该架构,指出按模型类别建立分类索引,能够提高空间索引查询效率。     

基于NetCDF数据模型的海洋环境数据三维可视化研究

针对海洋环境数据多维、多格式及动态性等特点,本文在全面分析NetCDF数据模型的原理、数据组织及其调度方法的基础上,基于大范围三维虚拟场景,设计了符合NetCDF标准典型海洋环境要素的三维动态渲染模型,实现了海洋环境要素数据的三维动态可视化表达与分析。实验表明,本文方法为复杂海洋现象的表达、变化规律分析以及趋势预测等研究提供强有力的可视化辅助工具。     

时空数据模型及其可视化技术初探

目前较好的空间数据模型是三维数据模型 ,但它存在很大的不足 ,不能描述第四维 :时间和变化 ,表现不出动态的特性。因此 ,我们需要在空间模型中引入时间的概念 ,构造时空一体化数据模型。本文对时空数据模型进行了简要的探讨 ,同时也探讨了时空数据模型的可视化问题     

面向地质建模的三维体元拓扑数据模型研究

在对地质对象的基本特征和计算机三维地质建模的基本要求进行讨论的基础上，提出了面向对象的三维体元拓扑数据模型。在该数据模型中，用面向对象的方法将地质对象抽象为点、线、面、体，体类又进一步划分为复合体、复杂体、简单体和体元四类。对所有对象类设计了12种拓扑关系和相应的数据结构。