Skip to main content
main-content

Über dieses Buch

The book presents a collection of accepted papers from the 3DGeoinfo 2015 international conference held in Kuala Lumpur, Malaysia from October 28 – 30, 2015. All papers underwent double-blind review by experts from around the globe. The conference brought together pioneering international researchers and practitioners to facilitate the dialogue on emerging topics in the field of 3D geo-information. The focus areas include: - Data Collection and Modeling: advanced approaches for 3D data collection, reconstruction and methods for representation- Data Management: topological, geometrical and network models for maintenance of 3D geoinformation- Data Analysis and Visualization: frameworks for representing 3D spatial relationships, 3D spatial analysis and algorithms for navigation, interpolation, advanced VR, AR and MR visualisation, as well as 3D visualization on mobile devices- 3D Applications: city models, Cadastre, LBS, etc.

Inhaltsverzeichnis

Frontmatter

Realistic Benchmarks for Point Cloud Data Management Systems

Lidar, photogrammetry, and various other survey technologies enable the collection of massive point clouds. Faced with hundreds of billions or trillions of points the traditional solutions for handling point clouds usually under-perform even for classical loading and retrieving operations. To obtain insight in the features affecting performance the authors carried out single-user tests with different storage models on various systems, including Oracle Spatial and Graph, PostgreSQL-PostGIS, MonetDB and LAStools (during the second half of 2014). In the summer of 2015, the tests are further extended with the latest developments of the systems, including the new version of Point Data Abstraction Library (PDAL) with efficient compression. Web services based on point cloud data are becoming popular and they have requirements that most of the available point cloud data management systems can not fulfil. This means that specific custom-made solutions are constructed. We identify the requirements of these web services and propose a realistic benchmark extension, including multi-user and level-of-detail queries. This helps in defining the future lines of work for more generic point cloud data management systems, supporting such increasingly demanded web services.
Peter van Oosterom, Oscar Martinez-Rubi, Theo Tijssen, Romulo Gonçalves

Does a Finer Level of Detail of a 3D City Model Bring an Improvement for Estimating Shadows?

3D city models are characterised by the level of detail (LOD), which indicates their spatio-semantic complexity. Modelling data in finer LODs results in visually appealing models and opens the door for more applications, but that is at the expense of increased costs of acquisition, and larger storage footprint. In this paper we investigate whether the improvement in the LOD of a 3D building model brings more accurate shadow predictions. The result is that in most cases the improvement is negligible. Hence, the higher cost of acquiring 3D models in finer LODs is not always justified. However, the exact performance is influenced by the architecture of a building. The paper also describes challenges in experiments such as this one. For instance, defining error metrics may not always be simple, and the big picture of errors should be considered, as the impact of errors ultimately depends on the intended use case. For example, an error of a certain magnitude in estimating the shadow may not significantly affect visualisation purposes, but the same error may considerably influence the estimation of the photovoltaic potential.
Filip Biljecki, Hugo Ledoux, Jantien Stoter

Interactive and View-Dependent See-Through Lenses for Massive 3D Point Clouds

3D point clouds are a digital representation of our world and used in a variety of applications. They are captured with LiDAR or derived by image-matching approaches to get surface information of objects, e.g., indoor scenes, buildings, infrastructures, cities, and landscapes. We present novel interaction and visualization techniques for heterogeneous, time variant, and semantically rich 3D point clouds. Interactive and view-dependent see-through lenses are introduced as exploration tools to enhance recognition of objects, semantics, and temporal changes within 3D point cloud depictions. We also develop filtering and highlighting techniques that are used to dissolve occlusion to give context-specific insights. All techniques can be combined with an out-of-core real-time rendering system for massive 3D point clouds. We have evaluated the presented approach with 3D point clouds from different application domains. The results show the usability and how different visualization and exploration tasks can be improved for a variety of domain-specific applications.
Sören Discher, Rico Richter, Jürgen Döllner

Representation of CityGML Instance Models in BaseX

The Open Geospatial Consortium standard CityGML is an application schema of GML 3.1.1 for the representation, storage and exchange of semantic-rich virtual 3D city models. Here we assess the feasibility of storing, querying and updating CityGML models in the native XML database system BaseX. The features and performance of BaseX are compared with the implementation of the 3DCityDatabase which stores CityGML models in a relational database system. The results show that BaseX is a fast, flexible and intuitive tool to store and query even large CityGML documents. Its main advantage is the schema-oblivious storage mechanism that allows schema changes without changes to the database layout and the fast import and export of CityGML models. Using the 3DCityDatabase to manage CityGML data on the other hand is a better choice when spatial analysis and integration with third party software are demanded.
Sabine Koch, Marc-O. Löwner

A Spatio-Semantic Query Language for the Integrated Analysis of City Models and Building Information Models

Distinct semantic-geometric data models are applied in architecture/engineering/construction and geospatial domains. However, to make decisions within complex urban planning and engineering tasks these two domains and their data models must be combinded. Currently, the necessary joint information is created by converting data between the two domains. Because the employed modelling differs conceptually, there is a high risk of information loss durring these conversions. To overcome this issue, we present a spatio-semantic query language that allows analysis of IFC building information models and geospatial CityGML models in an integrated context. Rather than converting between IFC and CityGML, a holistic information space is realized by an intermediate layer that abstracts from the two schemas of spatio-semantic modelling.
S. Daum, A. Borrmann, T. H. Kolbe

A Methodology for Modelling of 3D Spatial Constraints

In this work we demonstrate a new methodology to conceptualise and implement geo-constraints in 3D, which has not been widely explored yet. This is done in four stages from natural language to implementation, in which geometric primitives and Object Constraint Language (OCL) play a crucial role to formulate the constraints. A database including various 3D topographic objects (e.g. buildings, trees, roads, grass, water-bodies and terrains) from CityGML (no constraints yet) is used as a case study to apply the developed methodology. In this research, a first attempt to formulate 3D geo-constraints in OCL is made. Unified Modelling Language (UML) class diagram has been extended with graphical symbols for indicating constraints between classes (in addition to the additional compartment within a class for a class constraint). These constraint expressions can be tested and translated to other models/implementations when the OCL standard is extended with spatial types and operations. During this research, new types of constraints are defined as follows: general-level constraints (applicable to all object sub-classes), parameterised constraints (containing numeric values, e.g. maximum distance), constraints allowing exceptional instances (to resolve cases that have not been defined) and constraints relating to multi-scale representations (to check the consistency between two levels of detail which model the same object). Additionally common sense rules to detect conflicting constraints are specified as well.
Daniel Xu, Peter van Oosterom, Sisi Zlatanova

Reconstructing 3D Building Models with the 2D Cadastre for Semantic Enhancement

Virtual city models are increasingly used in urban land management processes, which involve the use of different sources of spatial information. This heterogeneous data is, however, often complementary and it may be necessary to give the possibility to join information provided by different sources. This paper presents a method to enhance 3D buildings by using usual 2D vectorial polygon database. These polygons may represent districts, building footprints, or any segmentation of the urban area that adds information to the city model. The enhancement consists in using this polygon database to split the 3D buildings into a set of city objects where each element possesses a 3D geometry and the semantic information of the polygon it is linked to. In this paper, for an illustration purpose, we will present how to create this link between 3D buildings and the cadastre map, in order to create a set of semantically rich 3D building models.
Frédéric Pedrinis, Gilles Gesquière

A 3D LADM Prototype Implementation in INTERLIS

The massive developments and uses of high-rise buildings indicate that the demand for use of space above and below the ground surface is rapidly increasing in recent years. The same applies to Greece, where the existing cadastral model does not cover the 3D needs and does not conform to international standards. In this paper, a model is proposed, considered as an effort for overcoming these shortcomings, based on international standards, including the representation of a wide range of different types of spatial units, organized in levels according to the LA_Level structure of ISO19152 LADM. It is a proposal for a comprehensive multipurpose LAS supporting 2D and 3D cadastral registration in Greece. A prototype system was developed to exploit the strengths and limitations of the proposed conceptual model, as well as to investigate the efficiency of technological tools. Experience from the prototype will be used to further improve the conceptual model. The steps that were followed were: the description of the prototype in UML diagrams, the implementation via INTERLIS, a Swiss standard modeling language for geodata exchange, the selection of the most appropriate technical model/format to implement and visualize the result in 3D environment and finally the conversion and/or creation of sample data into the model. In this paper it is explored how INTERLIS can be used in actual implementation of land administration system based on LADM. During the development of the prototype many design decision have been taken and these are then analyzed, together with technical problems and challenges for future work.
Eftychia Kalogianni, Efi Dimopoulou, Peter van Oosterom

Web-Based Tool for the Sustainable Refurbishment in Historic Districts Based on 3D City Model

The objective of this article is to describe a web-based tool that aims the management and conservation of urban heritage by means of the usage of a decision making system. The decision making system will be feed by a 3D city model of a historic district, enabling the storage and presentation of data at city and building scales. 3D city model contains both geometric and semantic data into a single data model. Access to stored city objects in the 3D city model is made through standard web services defined by the Open Geospatial Consortium (OGC). The presentation of the information is performed through an user friendly interface based on the interactive representation of the 3D city model using Web3D technologies (HTML5 and WebGL).
Iñaki Prieto, Jose Luis Izkara, Rubén Béjar

Terrestrial Laser Scanners Self-calibration Study: Datum Constraints Analyses for Network Configurations

Similar to other electronic instruments, terrestrial laser scanner (TLS) can also inherent with various systematic errors coming from different sources. Self-calibration technique is a method available to investigate these errors for TLS which were adopted from photogrammetry technique. According to the photogrammetry principle, the selection of datum constraints can cause different types of parameter correlations. However, the network configuration applied by TLS and photogrammetry calibrations are quite different, thus, this study has investigated the significant of photogrammetry datum constraints principle in TLS self-calibration. To ensure that the assessment is thorough, the datum constraints analyses were carried out using three variant network configurations: (1) minimum number of scan stations; (2) minimum number of surfaces for targets distribution; and (3) minimum number of point targets. Based on graphical and statistical, the analyses of datum constraints selection indicated that the parameter correlations obtained are significantly similar. In addition, the analysis has demonstrated that network configuration is a very crucial factor to reduce the correlation between the calculated parameters.
Mohd Azwan Abbas, Halim Setan, Zulkepli Majid, Albert K. Chong, Lau Chong Luh, Khairulnizam M. Idris, Mohd Farid Mohd Ariff

Managing Versions and History Within Semantic 3D City Models for the Next Generation of CityGML

Semantic 3D city models describe city entities by objects with thematic and spatial attributes and their interrelationships. Today, more and more cities worldwide are representing their 3D city models according to the CityGML standard issued by the Open Geospatial Consortium (OGC). Various application areas of 3D city models such as urban planning or architecture require that authorities or stakeholders manage parallel alternative versions of city models and their evolution over time, which is currently not supported by the CityGML standard 2.0. In this paper, we propose a concept and a data model extending CityGML by denoting versions of models or model elements as planning alternatives. We support transitions between these versions to manage history or evolution of the city models over time. This approach facilitates the interoperable integration and exchange of different versions of a 3D city model within one dataset, including a possibly complex history of a repository. Such an integrated dataset can be used by different software systems to visualize and work with all the versions. The versions and version transitions in our proposed data model are bi-temporal in nature. They are defined as separate feature types, which allow the users to manage versioning and to perform queries about versions using an OGC Web Feature Service. We apply this data model to a use case of planning concurrent versions and demonstrate it with example instance data. The concept is general in the sense that it can be directly applied to other GML-based application schemas including the European INSPIRE data themes and national standards for topography and cadasters like the British Ordnance Survey Mastermap or the German cadaster standard ALKIS.
Kanishk Chaturvedi, Carl Stephen Smyth, Gilles Gesquière, Tatjana Kutzner, Thomas H. Kolbe

Cartographic Enrichment of 3D City Models—State of the Art and Research Perspectives

This paper reports on cartographic enrichments of three dimensional geovirtual environments including the representation of 3D city models. In the recent years 3D city models have become effective and powerful tools that support the simulation and visualization of our real world in a more and more realistic and detailed way. At the same time, there is a growing interest in comprising more information in the virtual living environment in addition to interior and exterior geometric features, roof and facade textures. A lot of information is related to houses, floors, flats, rooms, etc. but also to persons or specific features at certain urban locations. The paper presents the state of the art of cartographic principles in 3D city models, discusses approaches of cartographic enrichments with the aim to bring added values to the visual exploration of 3D geovirtual environments and reveals missing cartographic design rules within this area.
Stefan Peters, Mathias Jahnke, Christian E. Murphy, Liqiu Meng, Alias Abdul-Rahman

Comparison of 2D & 3D Parameter-Based Models in Urban Fine Dust Distribution Modelling

In the present study two Land Use Regression Models for the estimation of urban fine dust distribution were established and compared. The first model used 2D parameters derived from an Open Street Map project data (OSM) and the second model used 3D parameters derived from a CityGML-based 3D city model. Both models predict fine-dust concentrations by using urban morphological (2D resp. 3D) and additional semantic parameters. The models were applied to a 2 km2 study area in Berlin, Germany. The 2D-LUR model explained 84 % of the variance of TNC for the full data set with root mean square error (RMSE) of 3284 cm−3 while the 3D-LUR explained 79 % of the variance with an RMSE of 3534 cm−3. Both models are capable to depict the spatial variation of TNC across the study area and showed relatively similar deviation from the measured TNC. The 3D-LUR needed less parameters than the 2D-LUR model. Furthermore, the semantic parameters (e.g. streets type) played a significant role in both models.
Yahya Ghassoun, M. -O. Löwner

Investigating Semantic Functionality of 3D Geometry for Land Administration

Significance of semantic data during the recent years is growing. This trend, combined with facilitation of new 3D object modeling has led to semantically enriched 3D models, serving various applications where relations between objects’ components and their environment need to be stored and presented. In the field of Land Administration, semantics can greatly contribute to optimize land management and land policies. Integration of semantics to 3D building models is currently achieved through two differently structured models: semantic-oriented CityGML and structural-oriented BIM/IFC. Integration of the semantic information of each model is still an object of intense research worldwide. In this paper, a 3D building model designed in SketchUp Pro software was transformed using FME software to a CityGML file; land use features were assigned to the model and attribute queries were executed in order to check the exported models’ functionality in terms of semantics.
George Floros, Eva Tsiliakou, Dimitrios Kitsakis, Ioannis Pispidikis, Efi Dimopoulou

3D Complete Traffic Noise Analysis Based on CityGML

Nowadays, transportation plays a more and more significant role in our daily life but produces noise. Noise not only causes annoyance and health problems, but also shows effects on economics. In 2002, the European Union published the Common Noise Assessment methods (Kephalopoulos et al. 2012). The objective of this paper is to present a method for simulating the noise propagation in 3D and calculating traffic noise on building façade level with different height by using 3D city model and integrating all noise coming from individual traffic such as cars or motorcycles as well as planes and railroad based vehicles. Since noise sources are located in our 3D urban environment—the analysis and the mapping has to cover the 3D aspect as well. A neighborhood of Berlin was chosen as research area. Currently, we propose a semi-automatic solution for 3D noise mapping: generating 3D observer points from CityGML building data; modeling 3D propagation path and calculating different kinds of traffic noise level. The total noise levels are then calculated by estimating the total annoyance based on effect equivalent sound pressure levels for different types of traffic source. The results are presented as a 3D map. In the future this approach can be further developed to an on-the-fly tool, that makes use publicly available data and processes to determine the noise for one building to a certain point in time. Besides that we found out that more investigation and evaluation on noise calculation methods are needed. Thus the development of near real time calculation methods together with noise measurements is required.
Lu Lu, Thomas Becker, Marc-Oliver Löwner

Highly Efficient Computer Oriented Octree Data Structure and Neighbours Search in 3D GIS

Three-dimensional (3D) visualization has given a new perspective in various fields such as urban planning, hydrology, infrastructure modelling and geology. This is due to its capability of handling real world object in more realistic manners, rather than the two-dimensional (2D) approach. However, implementation of 3D spatial analysis in the real world situations has proven to be difficult to comprehend due to the complexity of the algorithm, computational process and time consuming. The existing Geographical Information Systems (GIS) enable 2D and two-and-a-half-dimensional (2.5D) spatial datasets, but less capable of supporting 3D data structures. Recent development in Octree showed that more effort was given to improve the weakness of Octree in finding neighbouring nodes by using various address encoding scheme with specific rule like matrix, lookup table and arithmetic to eliminate the need of tree traversal. Therefore, the purpose of this paper is to propose a new method to speed up the neighbouring search by eliminating the needs of complex operation to extract spatial information from Octree by preserving 3D spatial information directly from the Octree data structure. This new method will be able to achieve O(1) complexity and utilizing Bit Manipulation Instruction 2 (BMI2) to speed up address encoding, extraction and voxel search 1000x compared to generic implementation.
Noraidah Keling, Izham Mohamad Yusoff, Habibah Lateh, Uznir Ujang

Framework for on an Open 3D Urban Analysis

The Open Geospatial Consortium (OGC) is the driving organization for the specification of Web Processing Services (WPS) that enables distributed execution of computing processes. However, WPS are not widely distributed in the field of urban analysis. We identified economic relevance of projects that hinder an open source like publication, complexity of projects and, therefore, limited reusability of code and algorithms from these projects, very specific and geographically bound projects, and, a lack of publication culture for the reluctance of publishing open accessible WPS. Here we present a general framework for the publication or reusable WPS that enables both, the full reusability of algorithms and the possibility to develop business models. A small scaled WPS, the AbstractKeyProcesses like Algorithm, Transformer and Inquirer are introduced for the publication of open accessible, atomic and reusable services. Further aggregated and more advanced analysis can be published by the use of KnowledgeBasedChainedProcesses that may be published either as open access or represent already business models. In a last step even complete projects may be implemented as so called ProblemSolvers. Being aware not to present a fully elaborated standard, we give information about the components, transfer values and communication in a conceptual way. Further, we discuss the benefits of this approach along an example of relevance in the field of urban analysis.
Marc-O. Löwner, Thomas Becker

Usability Assessment of a Virtual Globe-Based 4D Archaeological GIS

Acquired using 3D technologies, archaeological data is increasingly represented via 3D visualizations. For analysing, interpreting and exchanging, these data are unfortunately mostly reduced to two dimensions. Therefore, a 4D archaeological GIS that integrates 3D representations and analytical functionalities will contribute to different parts of the archaeological workflow from fieldwork preparation over analysis to reporting. Such a 4D approach will facilitate better and more integrated insights and allow more complex analyses and interpretations. Incorporating such a 4D archaeological GIS in a web-based environment will even increase the benefits as this could function as a virtual workspace. Since virtual globes have proven their capabilities to manage and visualize 3D data in non-expert applications, a prototypical 4D archaeological GIS was developed based on the virtual globe Cesium. This paper demonstrates by means of a usability test with employees of a Flemish archaeological organization that the concept of such a low-threshold application is supported by the intended end-users. Although some usability problems were encountered and the functionalities of the prototype are rather limited, extending and further developing the system could result in a valuable research tool for archaeology.
Berdien De Roo, Jean Bourgeois, Philippe De Maeyer

Temporal and Spatial Database Support for Geothermal Sub-surface Applications

Geothermal energy production from the deep subsurface requires a detailed knowledge of the relevant static and transient parameter distribution in the reservoir and host rock. In reservoir exploration, engineering and operation phases, both temporal and spatial subsurface parameters are acquired, evaluated and monitored in order to improve the reservoir performance. To support temporal and spatial data access to geothermal data sources, an efficient 3D/4D GIS is proposed in this study. We discuss theoretical and first practical approaches for the management of such temporal and spatial geothermal data. A first practical example is provided using the data acquired in the Soultz-sous-Forets geothermal project (France). A distributed software architecture, database design, and the concept for advanced query component with embedded simulations are presented. Finally, we give an outlook on the planned future research in 3D data management of subsurface, near-surface, and above-surface installations in other projects.
M. Jahn, M. Breunig, E. Butwilowski, P. V. Kuper, A. Thomsen, M. Al-Doori, E. Schill

Automatic Semantic and Geometric Enrichment of CityGML Building Models Using HOG-Based Template Matching

Semantically rich 3D building models give the potential for a wealth of rich geo-spatially-enabled applications such as cultural heritage augmented reality, urban planning, radio network planning and personal navigation. However, the majority of existing building models lack much if any semantic detail. This work demonstrates a novel method for automatically locating subclasses of windows and doors, using computer vision techniques including the histogram of oriented gradient (HOG) template matching, and automatically creating enriched CityGML content for the matched windows and doors. Good results were achieved for class identification with potential for further refinement of subclasses of windows and doors and other architectural features. It is part of a wider project to bring even richer semantic content to 3D geo-spatial building models.
Jon Slade, Christopher B. Jones, Paul L. Rosin

Stochastic Buildings Generation to Assist in the Design of Right to Build Plans

The design of documents impacting potential new constructions, such as Right to Build plans, is a complex issue. New tools need to be proposed in order to systematically assess the impact of regulations on the building potential of the concerned areas. Furthermore, it is often not directly the morphology of new constructions that administrations and citizens would like to regulate but their properties with regard to other phenomena (solar energy potential, etc.). In order to tackle these issues, we propose in this article to explore building configurations and regulations using a stochastic building generator and a workflow engine. The workflow we propose for such an exploration will produce important amounts of data that we intend to release as OpenData in order for administrations, urban planners and citizens to be able to freely visualize and collectively choose the regulations that best suit their territory. Such amount of 3D geographical data also suggests new issues in geovisualization.
Mickaël Brasebin, Julien Perret, Romain Reuillon

3D Marine Administration System Based on LADM

Oceans cover almost two-thirds of the Earth’s surface. They are the primary regulator of the global climate and sustain a huge variety of plant and animal life. Maritime environment needs to be organized and precisely determined, in order to be sustainable. The registration of marine legal boundaries is a necessary condition for the protection of a living organism, which flows, changes, reverses itself, but is not limitless. Research has confirmed that the common pattern of people-land relationship also exists in the marine environment. Moreover, the marine Cadastre concept suggests that the complexity of interests in marine space is similarly encountered in land. The extension of Cadastre functions from land to marine space is considered reasonable. An inventory of interests that exist in the marine environment is important. At the same time, laws that are the basis of these interests need to be identified and their effect qualified and visualized. The administration of the marine space remains partial and complex, mainly deriving from political interests and strategic benefits. This could be overcome by designing a marine administration system, in accordance with the international practices. A conceptual model may be considered as the base of such system. This model should clearly depict the relevant entities of the system and the relationships between them. Modeling and standardizing systems and processes at an international level, requires the harmonization with international standards and specifically with the ISO 19152—Land Administration Domain Model (LADM), which so far remains a challenge. The aim of this paper is to present how rights, restrictions and responsibilities (RRRs) relating to marine space may be organized, in order to develop a marine administration model based on LADM, followed by the database implementation, to support effective and efficient decision making in marine governance.
Aikaterini Athanasiou, Ioannis Pispidikis, Efi Dimopoulou

Assessing the Suitability of Using Google Glass in Designing 3D Geographic Information for Navigation

No longer are we bound by traditional 2D physical representations; there is a steady shift towards three-dimensional (3D) data. Existing research recognises landmarks to be important navigationally but specific requirements for geometric and semantic attributes in 3D have not been identified. This study assesses the suitability of using Google Glass in real-world experiments investigating the saliency of environmental objects which facilitate pedestrian navigation. From the experiment carried out with fourteen participants, initial results show geometric and semantic detail for navigation are most pertinent between 1.65–7.5 m for buildings. Visual characteristics such as colour, shape and texture are more relevant than function and use.
Kelvin Wong, Claire Ellul

Review and Assessment of Current Cadastral Data Models for 3D Cadastral Applications

Three-dimensional (3D) cadastres are often described as the 3D digital representation of real property rights, restrictions, and responsibilities (legal objects). They can also contain physical counterparts (physical objects) of legal objects such as buildings and utility networks, on, above or under the surface. Implementation of 3D cadastres requires many elements such as existing 3D property registration laws, appropriate 3D data acquisition methods, 3D spatial database management systems, and functional 3D visualisation platforms. In addition, an appropriate 3D cadastral data model can also play a key role to ensure successful development of the 3D cadastre. Many jurisdictions have defined their own cadastral data models. However, none of them can fully support the requirements of 3D cadastres. This paper aims to explore the theories and concepts of the most common existing cadastral data models and investigate how they manage 3D legal and physical data. The result of this research can be used by cadastral data modellers to improve existing or develop new cadastral data models to support the requirements of 3D cadastres.
Ali Aien, Abbas Rajabifard, Mohsen Kalantari, Ian Williamson

The Hierarchical Three-Dimensional (3D) Dynamic Water Infiltration on Multi-layers of Soil According to Voronoi Sequence Nodes Based on the Three-Dimensional Triangular Irregular Network (3D TIN)

Understanding soil water infiltration movement has been birthed from extensive interest and concern in the last few decades. The arrangement of particles (i.e. structures and sizes) and the interaction between both the soil and soil water have a profound effect on the soil water infiltration. The challenging task in the soil fluid modelling is the indeterminate spatial extent that has no specific boundaries and the fact that it is difficult to sense. Plenty of investigations and studies have been conducted to measure the water movement. However, less focus has been given on the movement of the dynamic soil water infiltration. This paper will focus on modelling the three-dimensional (3D) soil water infiltrations that flow downward due to the gravitational factor and gradient pressure. The 3D hierarchical soil water infiltration model proposes the integration of techniques which includes the Tree-map to isolate the depth of the soil that acts as a route of the soil water flow from the surface of the terrain to the subsurface flow. Moreover, the 3D Gosper curve is used to represent the soil water flow pattern that is based on the law of gravity and Horton equation, which control the flow of the soil water in the model. The curves that consist of a series of nodes adopt the Three-Dimensional Triangular Irregular Network (3D TIN) which creates a network of flow direction that allows the water to pass through the nodes according to a predetermined sequence. The study area has an average of 8.5 mm total rain and −5 m water level. The soil is divided into a few layers to represent the flow of the soil water according to the sequence of nodes. The soil depth (40, 80, 120, 160 and 200 cm) isolation in the form of Voronoi-shaped polygon nodes allows the soil water to flow down where the depth is chosen based on the soil wetting range of the subsurface soil.
Siti Nurbaidzuri Reli, Izham Mohamad Yusoff, Habibah Lateh, Uznir Ujang

A Data Model for the Interactive Construction and Correction of 3D Building Geometry Based on Planar Half-Spaces

3D city models of large areas can only be efficiently (re-)constructed using automatic approaches. But since there is always a certain number of buildings where the automation fails, there is a need for interactive construction and correction tools. These tools should ideally use the reconstruction results as input, so that the amount of manual labor is minimized. However, automatic 3D building reconstruction approaches make use of different solid modeling techniques that are not all suitable for interactive modeling purposes. One such representation is half-space modeling that exhibits several advantages for the automatic (re-)construction of 3D building models (from segmented point clouds). Because planar half-spaces are infinite entities that are usually represented as mathematical inequality equations, it is difficult to design an interactive modeling system that allows their direct manipulation. In this paper, we propose an interactive modeling concept specifically for 3D building geometry based on a half-space kernel. Following from it, a special-purpose object-oriented data model is developed that hides the kernel under a layer of parameterized primitives and boundary representation (B-rep) that give semantic meaning to building elements and is thus better comprehensible to human users.
Martin Kada, Andreas Wichmann, Nina Manzke, Yevgeniya Filippovska

The Potential of the 3D Dual Half-Edge (DHE) Data Structure for Integrated 2D-Space and Scale Modelling: A Review

Scaling factor is one of the most crucial aspect in 2D and 3D models especially in computer graphics, CAD, GIS, and games. Different user or/and application need different scale models during various stages of the use of data, including visualization and interaction. There are some arisen issues on 3D data model especially to meet GIS requirements while minimize the redundancy of the datasets. In GIS modelling, various data structures and data models have been proposed to support variety of applications and dimensionalities, but only a few in scale dimension. Some of them have succeeded in modelling scale such as in Space-Scale Cube (SSC) model. The recently implemented Dual Half-Edge (DHE) data structure within the PostgreSQL database is suitable for any valid 3D spatial model; not yet being explored for other dimensional such as scale environment. Using the same vario-scale approach, the DHE data model is also capable to implement a variable Level of Detail (LoD) representation such as SSC model. Some advantages of the DHE are described in this paper such as the dynamic property (valid updates based on Euler operations) and topology approach in comparison with other existing data structures. The last section of this paper describes capability of the DHE data structure to provide a better platform for GIS integrated space-scale data model.
Hairi Karim, Alias Abdul Rahman, Pawel Boguslawski, Martijn Meijers, Peter van Oosterom

Towards Integrating BIM and GIS—An End-to-End Example from Point Cloud to Analysis

Building Information Modelling (BIM) is becoming increasingly important within the UK, not least because of a UK Government directive that mandates Level 2 BIM for companies tendering for Government work, with the aim of reducing the cost of construction of public assets by 20–30 %. While this is aimed at new construction, it can be foreseen that a wider introduction of BIM could also result in savings during large refurbishment projects, which form a significant part of construction work in the UK, as well as during the occupancy phase of the building. However, unlike new projects, where the model for the BIM can be obtained from CAD drawings, deriving a detailed BIM for pre-existing structures requires some form of scan-to-BIM operation using laser scanning. To contribute to sustainability in construction, an underlying driver for BIM, the BIM must also be integrated with other data sources. Therefore, once the scan is complete, the resulting point cloud must be converted into geometry objects and geo-referenced for integration with Geographical data such as air quality or noise information. This paper presents an end-to-end example of this process, focusing in particular on the challenges of integrating BIM and GIS into one framework, and highlighting preliminary steps to be carried out during BIM creation in order to enable this to take place.
Claire Ellul, Gareth Boyes, Charles Thomson, Dietmar Backes
Weitere Informationen

Premium Partner

BranchenIndex Online

Die B2B-Firmensuche für Industrie und Wirtschaft: Kostenfrei in Firmenprofilen nach Lieferanten, Herstellern, Dienstleistern und Händlern recherchieren.

Whitepaper

- ANZEIGE -

Best Practices für die Mitarbeiter-Partizipation in der Produktentwicklung

Unternehmen haben das Innovationspotenzial der eigenen Mitarbeiter auch außerhalb der F&E-Abteilung erkannt. Viele Initiativen zur Partizipation scheitern in der Praxis jedoch häufig. Lesen Sie hier  - basierend auf einer qualitativ-explorativen Expertenstudie - mehr über die wesentlichen Problemfelder der mitarbeiterzentrierten Produktentwicklung und profitieren Sie von konkreten Handlungsempfehlungen aus der Praxis.
Jetzt gratis downloaden!

Bildnachweise