A Semantic-Sensitive Approach to Indoor and Outdoor 3D Data Organization

Building model data organization is often programmed to solve a specific problem,resulting in the inability to organize indoor and outdoor 3D scenes in an integrated manner.In this paper,existing building spatial data models are studied,and the characteristics of building information modeling standards(IFC),city geographic modeling language(CityGML),indoor modeling language(IndoorGML),and other models are compared and analyzed.CityGML and IndoorGML models face challenges in satisfying diverse application scenarios and requirements due to limitations in their expression capabilities.It is proposed to combine the semantic information of the model objects to effectively partition and organize the indoor and outdoor spatial 3D model data and to construct the indoor and outdoor data organization mechanism of“chunk-layer-subobject-entrances-area-detail object.”This method is verified by proposing a 3D data organization method for indoor and outdoor space and constructing a 3D visualization system based on it.

Unified Data Model of Urban Air Pollution Dispersion and 3D Spatial City Model:Groundwork Assessment towards Sustainable Urban Development for Malaysia

Understanding the behavior of urban air pollution is important en route for sustainable urban development (SUD). Malaysia is on its mission to be a developed country by year 2020 comprehends dealing with air pollution is one of the indicators headed towards it. At present monitoring and managing air pollution in urban areas encompasses sophisticated air quality modeling and data acquisition. However, rapid developments in major cities cause difficulties in acquiring the city geometries. The existing method in acquiring city geometries data via ground or space measurement inspection such as field survey, photogrammetry, laser scanning, remote sensing or using architectural plans appears not to be practical because of its cost and efforts. Moreover, air monitoring stations deployed are intended for regional to global scale model whereby it is not accurate for urban areas with typical resolution of less than 2 km. Furthermore in urban areas, the pollutant dispersion movements are trapped between buildings initiating it to move vertically causing visualization complications which imply the limitations of existing visualization scheme that is based on two-dimensional (2D) framework. Therefore this paper aims is to perform groundwork assessment and discuss on the current scenario in Malaysia in the aspect of current policies towards SUD, air quality monitoring stations, scale model and detail discussion on air pollution dispersion model used called the Operational Street Pollution Model (OSPM). This research proposed the implementation of three-dimensional (3D) spatial city model as a new physical data input for OSPM. The five Level of Details (LOD) of 3D spatial city model shows the scale applicability for the dispersion model implementtation. Subsequently 3D spatial city model data commonly available on the web, by having a unified data model shows the advantages in easy data acquisition, 3D visualization of air pollution dispersion and improves visual analysis of air quality monitoring in urban areas.

AN INTEGRATED DATA MODEL IN THREE DIMENSIONAL GIS

The current GIS can only deal with 2-D or 2.5-D information on the earth surface. A new 3-D data structure and data model need to be designed for the 3-D GIS. This paper analyzes diverse 3-D spatial phenomena from mine to geology and their complicated relations, and proposes several new kinds of spatial objects including cross-section, column body and digital surface model to represent some special spatial phenomena like tunnels and irregular surfaces of an ore body. An integrated data structure including vector, raster and object-oriented data models is used to represent various 3-D spatial objects and their relations. The integrated data structure and object-oriented data model can be used as bases to design and realize a 3-D geographic information system.

A Preliminary Review on Three-Dimensional City Model

In this paper a review on current research on 3DCM is presented, and an alternative approach by integrating the concepts and techniques of object\|oriented method and Computer Aided Design (CAD) is suggested. Through the approach urban spatial entities as objects are extracted, which are represented with primary 3D elements (node, edge, face and body) and their combinations. In the light of the concept of object, the method supports the multiple representation of Level of Details (LOD). More importantly, topological relationships between objects are described so that 3D topological operations can be implemented.

Numerical modeling calculation for the spatial distribution characteristics of horizontal field transfer functions

Applying 3-dimension finite difference method, the distribution characteristics of horizontal field transfer functions for rectangular conductor have been computed, and the law of distribution for Re-part and Im-part has been given. The influences of source field period, the conductivity, the buried depth and the length of the conductor on the transfer functions were studied. The extrema of transfer functions appear at the center, the four corners and around the edges of conductor, and move with the edges. This feature demonstrates that around the edges are best places for transfer functions' observation.

Inversion of gravity gradient data based on spatial gradient weighting

Compared with traditional gravity measurement data,gravity gradient tensor data contain more high frequency information,which can be used to understand the earth's interior structure,mineral resources distribution etc. In this study,the authors present an algorithm for inverting gravity gradiometer data to recover the three-dimensional( 3-D) distributions of density. Spatial gradient weighting was used to constrain the extent of the body horizontally and vertically. A more accurate inversion result can be obtained by combining the prior information into the weighting function and applying it in inversion. This method was tested on synthetic models and the inverted results showed that the resolution was significantly improved. Moreover,the algorithm was applied to the inversion of empirical data from a salt dome located in Texas,USA,which demonstrated the validity of the proposed method.

3D Spatial Information Intended for SDI: A Literature Review, Problem and Evaluation

In this paper, first we are going to discuss briefly the importance of 3D information, and its application because of the Increasing demand for detailed information about real world objects and phenomena including altimetry and planimetry data (X, Y, Z), then we will explain in short the available methods for 3D measurement. It’s important to note that the Information collection by itself cannot define and sufficiently provide all the necessary actions to be taken in order to get them accessible and useful for users. The data management and establishment of a proper and reliable DBMS and finally a GIS system at the same time are vital crucial in the course of 3D application that will be discussed throughout the paper. The existing drawbacks and elements needed to be considered for the cartographic presentation are the key issues in three-dimensional world visualization. The elaboration on the 3D information and its knowledge transfer to the users in a SDI framework as well as the requirement recognition of beneficiary organizations will be the next step in this paper and the most probable problems will be studied in this stage. At the final stage, we’ll come up with conclusion, warnings and recommendation.

Study on 3D Geological Model of Highway Tunnels Modeling Method

Geology is the base for highways and tunnels construction. With the fast development of national highway construction, highway tunnel construction project are more and more complex. The completeness and accuracy are essential for the planning, design and construction of projects, while the ground information is quite poor in systematic, reliable and timely aspects. Therefore, the development of underground road tunnels, and the implementation of informationized spatial information management is urgent for highway construction. 3D geological tunnel model is intuitive, high efficient and convenience which greatly facilitates the maintenance and security of highway tunnels construction and it will be the trend for the future highway tunnel development.

3维空间数据采集方法探讨

通过对地形3维空间数据在真实世界的位置表现研究,并借鉴国外已经开展的3维空间数据采集与应用的经验,以及对国内现行的国标分类代码与图式进行分析与研究,确定3维空间数据获取所需的核心要素的内容及采集方法。将3维地形要素分为几大类,对每一大类里面各要素的可获取性进行了详细的分析。同时为了兼顾出图的需要,对所需的2维地物要素采集进行了分析。

A 3D GIS spatial data model based on conformal geometric algebra

We propose a new Geographic Information System (GIS) three-dimensional (3D) data model based on conformal geometric algebra (CGA). In this approach, geographic objects of different dimensions are mapped to the corresponding basic elements (blades) in Clifford algebra, and the expressions of multi-dimensional objects are unified without losing their geometric meaning. Geometric and topologic computations are also processed in a clear and coordinates-free way. Under the CGA framework, basic geometrics are constructed and expressed by the inner and outer operators. This expression combined geometrics of different dimensions and metric relations. We present the structure of the framework, data structure design, and the data storage, editing and updating mechanisms of the proposed 3D GIS data model. 3D GIS geometric and topological analyses are performed by CGA metric, geometric and topological operators using an object-oriented approach. Demonstrations with 3D residence district data suggest that our 3D data model expresses effectively geometric objects in different dimensions, which supports computation of both geometric and topological relations. The clear and effective expression and computation structure has the potential to support complex 3D GIS analysis, and spatio-temporal analysis.

浅谈可视化3维GIS

根据目前3维GIS的相关发展情况,从3维可视化的表现形式、数据组织、关键技术等,简要介绍了3维GIS可视化技术。

Leveraging machine learning to generate a unified and complete building height dataset for Germany

Building geometry data is crucial for detailed, spatially-explicit analyses of the building stock in energy systems analysis and beyond. Despite the existence of diverse datasets and methods, a standardized and validated approach for creating a nation-wide unified and complete dataset of German building heights is not yet available. This study develops and validates such a methodology, combining different data sources for building footprints and heights and filling gaps in height data using an XGBoost machine learning algorithm. The XGBoost model achieves a mean absolute error of 1.78 m at the national level and between 1.52 m and 3.47 m at the federal state level. The goal is proving the applicability of the methodology at a large scale and creating a useful dataset. The resulting dataset is thoroughly evaluated on a building-by-building level and spatially resolved statistics on the quality of the dataset are reported. This detailed validation found that the building number and footprint area of German building stock is 90.31 % and 94.84 % correct, respectively, and the building height accuracy is 0.59 m at the national level. However, errors are not homogeneous across Germany and further research is needed into the impact of including additional datasets, especially for regions and building types with lower accuracies. This study proves that the chosen methodology is useful for generating a building height dataset and the workflow, with some modifications for regional data availability, can be transferred to other countries. The generated building dataset for Germany constitutes a valuable data basis for the research community in fields such as energy research, urban planning and building decarbonization policy development.

Modelling and mapping third dimension in a spatial database

In this paper,an overview of phases for modelling and mapping third dimension of spatial objects in a database is presented based on a selected spatial database management system(DBMS).These phases include(1)defining a spatial reference system for representing three-dimensional(3D)objects with real-world coordinates,(2)geometric modelling of 3D objects in the database,(3)3D spatial indexing for fast accessing/querying the 3D data,3D spatial queries and representation of 3D data.Then,a case study is performed to assess needs,possibilities and potential limitations of 3D data modelling in the spatial database.

基于几何元素的城市三维地理信息系统空间数据模型

空间数据模型是建立城市三维地理信息系统的核心问题。基于不同的城市空间对象划分方法 ,提出了城市三维地理信息系统的 18个空间数据模型 :①把空间现象抽象为点对象、线对象、规则面对象、规则体对象、不规则对象和DTM等 6类对象 ,基于 6种几何元素 (点、直线段、多边形、函数构造面、TIN面片、规则体素 )的不同组合 ,提出了城市三维地理信息系统的 9个空间数据模型 ;②把空间现象抽象为 5类对象 ,分别为零维空间对象 (点对象 )、一维空间对象 (线对象 )、二维空间对象 (面对象 )、三维空间对象 (体对象 )和DTM ,基于 6种几何元素的不同组合提出了 8个空间数据模型 ;③把空间现象抽象为零维对象、一维对象、二维对象、三维对象和DTM ,基于点、直线段、TIN面片、多边形、规则面、不规则面等 6类几何元素提出了一个空间数据模型。通过对一个数据模型的实验验证和各模型的理论分析 ,说明了这些模型的特点及可行性。

考古地层的三维建模方法在秦始皇帝陵考古勘探中应用尝试

为了更清楚地展示秦始皇帝陵地区考古地层的三维空间关系,并为后期考古工作中空间数据挖掘做准备,借鉴三维地质建模技术,提出了考古地层三维建模方法。基于探孔数据构建了考古地层三维模型。该模型清楚地展示了秦始皇帝陵地区考古地层的三维空间关系,为田野考古数字化工作提供一种新思路、新方法。

Multimodality image registration and fusion using neural network

Multimodality image registration and fusion are essential steps in building 3-D models from remotesensing data. We present in this paper a neural network technique for the registration and fusion of multimodali-ty remote sensing data for the reconstruction of 3-D models of terrain regions. A FeedForward neural network isused to fuse the intensity data sets with the spatial data set after learning its geometry. Results on real data arepresented. Human performance evaluation is assessed on several perceptual tests in order to evaluate the fusionresults.

房地一体化不动产三维数据模型研究

房地不动产具备天然的立体特性,在三维空间中对其进行准确刻画是当前城市地上地下综合开发的关键问题,国内外学者已经提出了各类房地不动产数据模型,旨在解决房地不动产的管理与权利空间的三维表达问题。分析国内外学者的研究成果发现,国外学者提出的房地不动产数据模型多以地籍为核心展开,不能完全适用于我国的房地不动产管理;而国内学者虽兼顾了地籍和房产,但忽略了建筑实体、建筑空间与产权空间的关系,无法将房地不动产信息与建筑物信息模型(Building Information Modeling,BIM)整合,不利于房地不动产的精细化管理。针对以上问题,本文提出了基于IFC(Industry Foundation Classes)标准扩展的房地一体化三维不动产数据模型,并通过实例验证了该模型在我国房地不动产管理上是可行的。研究结果表明,本文提出的模型正确表达了各类建筑对象和产权对象,既可以支持业务相关的关联关系的查询,也支持GIS常见拓扑关系的查询和表达,该模型除了能表达符合我国体制的房地不动产对象外,还关联了BIM模型中的建筑构件、建筑空间,为城市建设与运维管理提供技术模型支持。