3D GIS与3D GMS中的空间构模技术

3DGIS和3DGMS是近10年来地学领域并行发展的两大领域,该文从研究对象,数据来源,空间参照,空间构模,拓扑描述,空间量算,空间分析及应用领域等方面分析了3DGIS和3DGMS异同,并从数学模型,高程特征,属性特征和构建方式等方面讨论并重新界定了空间维数问题,重点分析了空间构模技术,将3D GIS和3D GMS中的空间构模分为基于面模型,基于体模型和混合构模3大类,并进行了分析比较和讨论,指出3D GIS和3D GMS将殊途同归,并最终建立全要素的真3D地球信息系统。     

多视角三维仿真城市地图的实现方法

针对目前三维仿真城市地图展示中单一视角因视线遮挡造成信息丢失的问题,提出了一种多视角三维仿真地图方法,即通过多个可以互相切换的视角对三维仿真城市地图数据进行发布与展示,多视角三维仿真地图具有信息量大、色彩鲜明、形象立体的优点。该文在分析多视角三维仿真地图数据的基础上,给出了数据组织模型,提出了三维仿真地图的多视角逻辑坐标与地理坐标的转换方法,实现了多视角三维仿真城市地图的可视化。     

基于ArcGIS Engine的钻孔三维精细地质模型自动构建方法研究

针对ArcGIS软件复杂钻孔三维精细地质模型自动构建研究存在的不足,该文在简要分析MultiPatch三维空间数据模型和深入研究复杂钻孔三维空间精确定位方法的基础上,探讨了基于ArcGIS Engine的复杂钻孔三维精细地质模型自动构建工作流程,并从空间精确定位、属性精细表达两个层面对钻孔三维精细地质模型构建算法进行了设计与实现.经软件功能研发及实际应用检验表明,该研究能够有效实现复杂钻孔精细地质属性特征的三维空间精确定位及多尺度精细表达,为应用ArcGIS Engine自动构建复杂钻孔三维精细地质模型提供了一种新的有效途径,也可为基于ArcGIS Engine的复杂地质体三维可视化建模及精细地质属性表达研究提供应用借鉴.     

基于网格细分技术的三维地质模型光滑方法研究

针对粗糙的三维地质模型,利用网格细分技术,生成加密光滑的三维模型。分析网格细分技术在三维地质建模中的应用需求以及Loop细分和改进的蝶形细分技术,为保持地质体之间公共面数据的一致性,对"改进的蝶形细分法"做了进一步改进,增加了对边界约束的处理。探讨利用细分技术生成多分辨率模型,通过试验验证了该方法的有效性。     

面向山地灾害动态过程仿真的地形三维建模与可视化

基于山地灾害动态过程仿真需要的考虑,并针对该动态过程仿真时渲染数据量过大所造成的实时性较差的问题,提出了利用改进的三角形二叉树LOD算法实现地形三维建模与可视化的方法。算法对山地地形数据进行了分层和分块的预处理,用三角形二叉树表示地形网格,并结合视点和局部地形的粗糙程度,动态的载入所需的地形块和释放无用的地形块,使得内存中的地形数据维持在一定范围内。实验结果表明;在对地形渲染不失真的前提下,本方法能够有效地提高地形绘制的效率,可应用到大规模山地地形的三维建模与可视化中去,为整个山地灾害的动态过程仿真奠定了良好的基础。     

一种基于机载LiDAR和离散曲率的建筑物三维重建方法

机载LiDAR作为一种获取地物空间信息的新技术已得到广泛应用,但从LiDAR数据中重建建筑物三维模型方法的缺乏,是制约其进一步发展的瓶颈.该文介绍了一种自动与人机交互建模相结合的建筑物三维重建方法,首先基于离散曲率分析自动提取建筑物3D轮廓信息,然后将建筑物轮廓信息作为约束条件,使用模型驱动的ATOP算法实现建筑物自动建模,并支持对复杂建筑物人机交互建模.     

Establishing a national standard for 3D topographic data compliant to CityGML

This article describes a research project that realised a national standard for 3D geo-information. The standard was developed as part of a pilot in which more than 65 private, public and scientific organisations collaborated to analyse and push 3D developments in the Netherlands (run between March 2010 and June 2011). The 3D standard was established through several steps. First, a comparison between the existing 3D computer-aided design and GIS standards was carried out that selected the Open Geospatial Consortium (OGC) standard CityGML as the optimal 3D standard to align to. Second, the equivalent concepts in CityGML and the existing national standard for large-scale topography (Information Model Geography [IMGeo]) were identified. Third, IMGeo was extended to 3D following the principles of CityGML Application Domain Extensions. The model was tested by applying it to real data. Based on the experiences of this pilot, this article proposes a framework of guidelines and principles for extending CityGML for national purposes, deduced from the modelling experiences. This is a unique contribution since experiences on extending CityGML are new and not well described in the OGC CityGML specifications. Finally, this article presents the change requests (CRs) which have been submitted to OGC to make the CityGML standard more suited for integration with existing 2D topographic information models. The CRs were formulated based on experiences from developing this nationwide 3D standard.     

Embedding user-generated content into oblique airborne photogrammetry-based 3D city model

Oblique airborne photogrammetry-based three-dimensional (3D) city model (OAP3D) provides a spatially continuous representation of urban landscapes that encompasses buildings, road networks, trees, bushes, water bodies, and topographic features. OAP3D is usually present in the form of a group of unclassified triangular meshes under a multi-resolution data structure. Modifying such a non-separable landscape constitutes a daunting task because manual mesh editing is normally required. In this paper, we present a systematic approach for easily embedding user-generated content into OAP3D. We reduce the complexity of OAP3D modification from a 3D mesh operation to a two-dimensional (2D) raster operation through the following workflow: (1) A region of interest (ROI) is selected to cover the area that is intended to be modified for accommodating user-defined content. (2) Spatial interpolation using a set of manually controlled elevation samples is employed to generate a user-defined digital surface model (DSM), which is used to reform the ROI surface. (3) User-generated objects, for example, artistically painted road textures, procedurally generated water effects, and manually created 3D building models, are overlaid onto the reformed ROI.     

面向三维地质建模的领域本体逻辑结构与构建方法

结合三维地质建模的应用,分析面向三维地质建模的领域本体的组成和层次结构.结合地质语义的特点,提出突出概念间关系的五元组逻辑结构和基于迭代思想的构建方法.该逻辑结构由概念、概念间语义关系、概念间层次关系、属性和实例组成.基于迭代思想的构建方法分为需求分析、领域共享词语的字典库构建、本体表示、本体集成和本体评估等步骤.以OWL语言描述工具,结合正断层本体实例探讨了面向三维地质建模领域本体逻辑结构的描述和构建方法.     

基于虚拟钻孔的工程地质三维剖切的实现

给出工程地质数据库的结构,并利用标准地层层序表和钻孔数据,根据层面TIN模型,建立了工程地质三维模型;在此基础上提出一种实用的工程地质三维剖切的实施方法,该方法通过剖切平面与层面TIN边的交点生成虚拟钻孔,把虚拟钻孔所在的地质剖面作为约束条件,将虚拟钻孔和实测钻孔一起重新构建层面TIN模型,并实现工程地质三维剖切。该方法简易可行,对层状地质结构的三维剖切效果较好,能满足工程地质分析和地质解释等应用的实际需要。     

城市三维地质信息系统初探

地质问题已成为影响城市可持续发展的一个基础性问题,利用现代信息技术构建一个集信息输入、数据库管理和三维地质数据可视化分析功能于一体的城市三维地质信息系统,可有效满足城市发展对地质信息不断增长的需求。该文阐述了城市三维地质信息系统的建设目标和研究内容,认为其是一个集城市地表、地上、地下多维、动态空间信息于一体的大型综合性空间信息系统。介绍了系统涉及的数据、系统功能特征和总体架构,指出了城市三维地质信息系统的发展方向和需要重点解决的关键性技术问题。     

基于空间推理的巷道三维拓扑建立

基于空间关系和空间推理理论,结合MGIS领域的需求建立巷道三维拓扑网络模型,研究巷道三维空间关系推理的算法及业务逻辑实现;开发巷道三维拓扑自动生成系统,实现了巷道空间与属性数据管理、三维拓扑自动处理、多尺度成果输出及基于三维拓扑的路径查询,为基于巷道的通风、运输、避灾、多尺度变换等应用奠定了基础。     

Vario-scale data structures supporting smooth zoom and progressive transfer of 2D and 3D data

This paper introduces the concept of the smooth topological Generalized Area Partitioning (tGAP) structure represented by a space-scale partition, which we term the space-scale cube. We take the view of ‘map generalization as extrusion of data into an additional dimension’. For 2D objects the resulting vario-scale representation is a 3D structure, while for 3D objects the result is a 4D structure.

This paper provides insights in: (1) creating valid data for the cube and proof that this is always possible for the implemented 2D tGAP generalization operators (line simplification, merge and split/collapse), (2) obtaining a valid 2D polygonal map representation at arbitrary scale from the cube, (3) using the vario-scale structure to provide smooth zoom and progressive transfer between server and client, (4) exploring which other possibilities the cube brings for obtaining maps having non-homogenous scales over their domain (which we term mixed-scale maps), and (5) using the same principles also for higher dimensional data; illustrated with 3D input data represented in a 4D hypercube.

The proposed new structure has very significant advantages over existing multi-scale/multi-representation solutions (in addition to being truly vario-scale): (1) due to tight integration of space and scale, there is guaranteed consistency between scales, (2) it is relatively easy to implement smooth zoom, and (3) compact, object-oriented encoding is provided for a complete scale range.     

Towards generating highly detailed 3D CityGML models from OpenStreetMap

About one decade has passed since US vice president Al Gore articulated his vision of Digital Earth (DE). Within this decade, a global multi-resolution and three-dimensional (3D) representation of the Earth, which sums up the DE vision, increasingly gained interest in both public and science. Due to the desired high resolution of the available data, highly detailed 3D city models comprise a huge part of DE and they are becoming an essential and useful tool for a range of different applications. In the past as well as at present, 3D models normally come from a range of different sources generated by professionals, such as laser scans or photogrammetry combined with 2D cadaster data. Some models are generated with semi-automated or fully automated approaches, but in most cases manual fine tuning or even manual construction from architectural plans is required. Further beyond outdoor city models, DE additionally envisages the provision of indoor information. That is, the interior structure of public or publically accessible buildings, such as airports or shopping malls, is represented and made available in 3D; however, at the moment, such models are mostly created by hand and essentially based on professional data sources. In contrast to such professional data, which is mainly captured by surveyors or companies, the last few years revealed the phenomenon of crowdsourced geodata, which receives an increasing attractiveness as an alternative data source for many Geographic Information Systems (GIS). Former research already demonstrated the power and richness of such geodata – especially OpenStreetMap (OSM) – and it has also been proved that this non-standardized, crowdsourced geodata can be combined with international standards of the Open Geospatial Consortium (OGC). For example, CityGML Level-of-Detail 1 (LoD1) and LoD2 models have already been created automatically from OSM. The research presented in this article will further continue on the automated generation of CityGML models from OpenStreetMap. Essentially, a method for the creation of highly detailed CityGML LoD4 models with interior structures will be explained. By applying the invented approach on existing OSM data, limitations and restrictions of the IndoorOSM mapping proposal, the available data and the developed approach are revealed and discussed.     

Spatial subdivision of complex indoor environments for 3D indoor navigation

As we realize that we spend most of our time in increasingly complex indoor environments, applications to assist indoor activities (e.g. guidance) have gained a lot of attention in the recent years. The advances in ubiquitous computing made possible the development of several spatial models intending to support context-aware and fine-grained indoor navigation systems. However, the available models often rely on simplified representations (e.g. 2D plans) and ignore the indoor features (e.g. furniture), thereby missing to reflect the complexity of the indoor environment. In this paper, we introduce the Flexible Space Subdivision framework (FSS) that allows to automatically identify the spaces that can be used for indoor navigation purpose. We propose a classification of indoor objects based on their ability to autonomously change location and we define a spatial subdivision of the indoor environment based on the classified objects and their functions. The framework can consider any 3D indoor configuration, the static and dynamic activities it hosts and it enables the possibility to consider all types of locomotion (e.g. walking, flying, etc.). It relies on input 3D models with geometric, semantic and topological information and identifies a set of subspaces with dedicated properties. We assess the framework against criteria defined in previous researches and we provide an example.     

摄影测量三维重建中多源信息融合方法探讨

分析摄影测量三维重建中不同数据源的特点,针对现有多源数据融合存在的有限数据源低层次融合问题,提出一种基于影像特征、GIS信息和3D TIN模型融合的层次结构与算法流程 .该算法主要包括多边形区域增长、几何推理和建筑物几何模型平差等处理,为基于摄影测 量的三维城市模型自动重建提供了一种新的思路与方法.     

基于GIS的自适应三维古海面-地面演变模型研究

本文设计了基于GIS的具有"自适应"功能的三维古海面-地面演变模型.该模型可以动态演绎沿海地区"沧海桑田"的变化景象,并且可以运用历史资料及专家知识,对海面-地面变化模拟结果进行检验,根据检验结果来对模型的一系列控制参数进行自动半自动的修订,然后重新进行海面-地面演变的动态模拟,直到更趋近于真实的历史演变过程,从而实现...     

3D noise mapping in urban areas

Noise mapping is the process of determining and visualizing noise impact on the environment in order to support environmental policies. Currently most noise impact studies are based on a 2D approach. The 3D output of noise simulation software is processed and visualized in 2D and combined with 2D topographical and other data, such as population distribution, to quantify the effects. The research described in this paper aims at improving visualization and assessment of noise impact on the environment by generating a 3D noise map in cases where 3D effects are relevant. Based on the specific demand, an approach is presented to generate a 3D noise map as a basis for noise impact studies. The proposed concept is proofed by applying it to a sample noise impact study. From experiences with the sample, it can be concluded that the 3D noise map offers significant insight in situations where 3D noise effects are relevant, i.e. in urban areas. Here, current 2D noise maps have limitations. In addition, more accurate assessment of noise impact is possible in particular when different floors of a building close to the noise source and/or behind noise barriers are considered. This paper also elaborates on accuracy aspects in all phases of noise modelling, including a presentation of initial experiments of 3D noise interpolation.     

基于Hoops的钻孔三维可视化技术研究

在矿体三维可视化建模过程中,钻孔和品位的三维可视化是其关键步骤之一,该文引进三维图形引擎库Hoops,采用Windows编程语言VC实现了钻孔轨迹及其品位分布三维可视化组件,为开发矿体的三维实体模拟软件系统奠定基础。工程应用表明,该组件性能稳定,能够精准地模拟实际钻孔分布情况。