scholarly journals A PROPOSAL FOR AN IMPROVED TRANSPORTATION MODEL IN CITYGML

2018 ◽  
Vol XLII-4/W10 ◽  
pp. 89-96 ◽  
Author(s):  
A. Labetski ◽  
S. van Gerwen ◽  
G. Tamminga ◽  
H. Ledoux ◽  
J. Stoter
Keyword(s):  
Data Model ◽  
Open Data ◽  
Use Cases ◽  
Water Bodies ◽  
Government Agencies ◽  
Transportation Model ◽  
3D City Models ◽  
Transportation Applications ◽  
City Models

<p><strong>Abstract.</strong> CityGML, an OGC standard, is an open data model for virtual 3D city models and includes buildings, roads, terrain, water bodies, etc. While many modules are well-developed (eg buildings, bridges, tunnels), the transportation model is, based on our consultations with various government agencies and municipalities, not sufficient for most transportation applications. We propose in this paper several improvements to the CityGML v2.0 Transportation module, and to the previous efforts for improving it. Our additions are based on the consultations we had, and on the use-cases that were identified. We argue that the following changes are necessary: A) multi-LoD modelling of roads, B) carriageway representation, C) detailed intersection modelling and, D) introducing waterways as a new sub-class.</p>

scholarly journals A PROPOSAL FOR GENERALIZATION OF 3D MODELS

2017 ◽  
Vol IV-4/W4 ◽  
pp. 389-392 ◽  
Author(s):  
A. Uyar ◽  
N. N. Ulugtekin
Keyword(s):  
Data Model ◽  
3D Model ◽  
Open Data ◽  
3D Models ◽  
3D Modelling ◽  
3D City Models ◽  
Model Generalization ◽  
Level Of Details ◽  
Future Work ◽  
City Models

In recent years, 3D models have been created of many cities around the world. Most of the 3D city models have been introduced as completely graphic or geometric models, and the semantic and topographic aspects of the models have been neglected. In order to use 3D city models beyond the task, a generalization is necessary. CityGML is an open data model and XML-based format for the storage and exchange of virtual 3D city models. Level of Details (LoD) which is an important concept for 3D modelling, can be defined as outlined degree or prior representation of real-world objects. The paper aim is first describes some requirements of 3D model generalization, then presents problems and approaches that have been developed in recent years. In conclude the paper will be a summary and outlook on problems and future work.

scholarly journals INVESTIGATING INTEROPERABILITY CAPABILITIES BETWEEN IFC AND CITYGML LOD 4 – RETAINING SEMANTIC INFORMATION

2018 ◽  
Vol XLII-4/W10 ◽  
pp. 33-40 ◽  
Author(s):  
G. S. Floros ◽  
C. Ellul ◽  
E. Dimopoulou
Keyword(s):  
Semantic Information ◽  
Open Data ◽  
3D Models ◽  
Solar Panels ◽  
3D City Models ◽  
Information Models ◽  
Building Information ◽  
Consistent Manner ◽  
3D Information ◽  
City Models

<p><strong>Abstract.</strong> Applications of 3D City Models range from assessing the potential output of solar panels across a city to determining the best location for 5G mobile phone masts. While in the past these models were not readily available, the rapid increase of available data from sources such as Open Data (e.g. OpenStreetMap), National Mapping and Cadastral Agencies and increasingly Building Information Models facilitates the implementation of increasingly detailed 3D Models. However, these sources also generate integration challenges relating to heterogeneity, storage and efficient management and visualization. CityGML and IFC (Industry Foundation Classes) are two standards that serve different application domains (GIS and BIM) and are commonly used to store and share 3D information. The ability to convert data from IFC to CityGML in a consistent manner could generate 3D City Models able to represent an entire city, but that also include detailed geometric and semantic information regarding its elements. However, CityGML and IFC present major differences in their schemas, rendering interoperability a challenging task, particularly when details of a building’s internal structure are considered (Level of Detail 4 in CityGML). The aim of this paper is to investigate interoperability options between the aforementioned standards, by converting IFC models to CityGML LoD 4 Models. The CityGML Models are then semantically enriched and the proposed methodology is assessed in terms of model’s geometric validity and capability to preserve semantics.</p>

Utilities of Virtual 3D City Models Based on CityGML: Various Use Cases

2018 ◽  
Vol 46 (6) ◽  
pp. 957-972 ◽  
Author(s):  
Sameer Saran ◽  
Kapil Oberai ◽  
Parag Wate ◽  
Amol Konde ◽  
Arnab Dutta ◽  
...  
Keyword(s):  
Use Cases ◽  
3D City Models ◽  
City Models

scholarly journals Incorporating Topological Representation in 3D City Models

2019 ◽  
Vol 8 (8) ◽  
pp. 347 ◽  
Author(s):  
Stelios Vitalis ◽  
Ken Ohori ◽  
Jantien Stoter
Keyword(s):  
Data Structure ◽  
Data Model ◽  
Semantic Information ◽  
Semantic Representation ◽  
Geometric Analysis ◽  
Computationally Efficient ◽  
Real World Data ◽  
3D City Models ◽  
Map Data ◽  
City Models

3D city models are being extensively used in applications such as evacuation scenarios and energy consumption estimation. The main standard for 3D city models is the CityGML data model which can be encoded through the CityJSON data format. CityGML and CityJSON use polygonal modelling in order to represent geometries. True topological data structures have proven to be more computationally efficient for geometric analysis compared to polygonal modelling. In a previous study, we have introduced a method to topologically reconstruct CityGML models while maintaining the semantic information of the dataset, based solely on the combinatorial map (C-Map) data structure. As a result of the limitations of C-Map’s semantic representation mechanism, the resulting datasets could suffer either from semantic information loss or the redundant repetition of them. In this article, we propose a solution for a more efficient representation of geometry, topology and semantics by incorporating the C-Map data structure into the CityGML data model and implementing a CityJSON extension to encode the C-Map data. In addition, we provide an algorithm for the topological reconstruction of CityJSON datasets to append them according to this extension. Finally, we apply our methodology to three open datasets in order to validate our approach when applied to real-world data. Our results show that the proposed CityJSON extension can represent all geometric information of a city model in a lossless way, providing additional topological information for the objects of the model.

scholarly journals Urban remote sensing with lidar for the Smart City Concept implementation

2019 ◽  
Keyword(s):  
Remote Sensing ◽  
Data Mining ◽  
Urban Environment ◽  
Smart City ◽  
Use Cases ◽  
3D City Models ◽  
Core Node ◽  
Mining City ◽  
Urban Remote Sensing ◽  
City Models

Introduction of the problem. The paper emphasizes that the key features of the contemporary urban development have caused a number of challengers, which require the innovative technological introductions in urban studies. The research goal of this paper means representing a multifunctional approach, which combines author’s urbogeosystem (UGS) theory with the URS (Urban Remote Sensing) technique for LiDAR (Light Detection And Ranging) data processing. The key elements of the Smart City concept within a geospatial perspective. Three basic assumptions are implied due to the affiliation “a geospatial perspective ó the Smart City concept” (SCC). The five key elements of the SCC have been outlined: Innovations; Scalability; Data gathering, measuring, and mining; Addressing environmental challengers; Interlink between the smart meter information and the geo-sensor information. The urbogeosystemic approach as a tool for simulating the “smart urban environment” – a core node of the Smart City hierarchy. The urbogeosystemic ontological model has been introduced as a trinity-tripod (urban citizens, municipal infrastructure, urbanistic processes and phenomena). The “smart urban environment” is a core node of an urbogeosystem. Processing results of LiDAR surveying technique. With increasing availability of LiDAR data, 3D city models of robust topology and correct geometry have become the most prominent features of the urban environment. Three key advantages of the LiDAR surveying technique have been introduced. The flowchart of the operational URS / LiDAR / GIS workflow for the Smart City implementation has been depicted. Urban Remote Sensing for data mining / city analytics and the EOS LiDAR Tool. ELiT (EOS LiDAR Tool) software is both a separate web-based (network) generator (an engine) – ELiT Server, and an integrated component of EOS Platform-as-a-Service software – ELiT Cloud. The allied one to these two products is our desktop ElitCore software, that possesses even broader functionality. The paper outlines the whole framework of urban data mining / city analytics relevant to the mentioned applications. The ELiT software use cases for the Smart Cities. A number of use cases that can be completed with the ELiT software in the common urban planning domain have been described and illustrated. Each from five scenarios presented suggests some unique solution within the frameworks of the SCC implementation. Conclusion, future research and developments. The completed research results have been summarized. An entity of the urban geoinformation space has been introduced. A geodatabase of ELiT 3D city models has been assigned a mandatory key component of the urban decision support system.

scholarly journals GENERATION OF MULTI-LOD 3D CITY MODELS IN CITYGML WITH THE PROCEDURAL MODELLING ENGINE RANDOM3DCITY

2016 ◽  
Vol III-4/W1 ◽  
pp. 51-59 ◽  
Author(s):  
F. Biljecki ◽  
H. Ledoux ◽  
J. Stoter
Keyword(s):  
Spatial Analysis ◽  
Open Source ◽  
Use Cases ◽  
3D City Models ◽  
Alternative Approach ◽  
Multiple Levels ◽  
Synthetic Datasets ◽  
City Models

The production and dissemination of semantic 3D city models is rapidly increasing benefiting a growing number of use cases. However, their availability in multiple LODs and in the CityGML format is still problematic in practice. This hinders applications and experiments where multi-LOD datasets are required as input, for instance, to determine the performance of different LODs in a spatial analysis. An alternative approach to obtain 3D city models is to generate them with procedural modelling, which is &ndash; as we discuss in this paper &ndash; well suited as a method to source multi-LOD datasets useful for a number of applications. However, procedural modelling has not yet been employed for this purpose. Therefore, we have developed RANDOM3DCITY, an experimental procedural modelling engine for generating synthetic datasets of buildings and other urban features. The engine is designed to produce models in CityGML and does so in multiple LODs. Besides the generation of multiple geometric LODs, we implement the realisation of multiple levels of spatiosemantic coherence, geometric reference variants, and indoor representations. As a result of their permutations, each building can be generated in 392 different CityGML representations, an unprecedented number of modelling variants of the same feature. The datasets produced by RANDOM3DCITY are suited for several applications, as we show in this paper with documented uses. The developed engine is available under an open-source licence at Github at <a href=" http://github.com/tudelft3d/Random3Dcity"target="_blank">http://github.com/tudelft3d/Random3Dcity</a>.

scholarly journals SEMANTIC MODELING OF UTILITY NETWORKS IMPLEMENTATION OF USE CASES FOR DEHRADUN CITY

2018 ◽  
Vol XLII-5 ◽  
pp. 139-145 ◽  
Author(s):  
E. Vishnu ◽  
S. Saran
Keyword(s):  
Urban Space ◽  
Use Cases ◽  
Urban Systems ◽  
Subsurface Water ◽  
Network Data ◽  
Successful Implementation ◽  
3D Gis ◽  
3D City Models ◽  
Utility Network ◽  
City Models

<p><strong>Abstract.</strong> The current on-going boom in the field of Building Information Modeling (BIM) and 3D GIS is widely being explored for vast urban related applications, analyses and simulations. Large amount of 3D city models are created using various sources of data. Substantial studies are carried out for above-surface features in 3D city models. This ensures providing relevant information about various spatial analyses over the urban systems and environment. Relevant researches explored the numerous applications of 3D GIS such as disaster management, city administration, urban and environment planning, environmental studies, etc. Utility infrastructures (overhead, subsurface or on-surface) play the critical role in the urban space; still they are not considered in 3D city models. OGC CityGML is acting well behind these applications by integrating the geographic information, semantics and the various interdependencies information with the 3D city model. Moreover, comparative studies over the existing network data models make Utility Network ADE as the perfect approach for data modelling. This research proposes the methodology for 3D semantic modelling of subsurface water supply network along with its various „subsurface, overhead and on-surface‟ utility network components with the help of OGC CityGML Utility Network ADE. This study is conducted for Dehradun area. As a result, semantically modelled utility network data is utilised for successful implementation of use cases such as 1) areas affected by utility failure; 2) street space affected by utility maintenance; and; 3) visualisation. These cases are investigated along with urban space.</p>

scholarly journals GENERATION OF MULTI-LOD 3D CITY MODELS IN CITYGML WITH THE PROCEDURAL MODELLING ENGINE RANDOM3DCITY

2016 ◽  
Vol IV-4/W1 ◽  
pp. 51-59 ◽  
Author(s):  
F. Biljecki ◽  
H. Ledoux ◽  
J. Stoter
Keyword(s):  
Spatial Analysis ◽  
Open Source ◽  
Use Cases ◽  
3D City Models ◽  
Alternative Approach ◽  
Multiple Levels ◽  
Synthetic Datasets ◽  
City Models

The production and dissemination of semantic 3D city models is rapidly increasing benefiting a growing number of use cases. However, their availability in multiple LODs and in the CityGML format is still problematic in practice. This hinders applications and experiments where multi-LOD datasets are required as input, for instance, to determine the performance of different LODs in a spatial analysis. An alternative approach to obtain 3D city models is to generate them with procedural modelling, which is – as we discuss in this paper – well suited as a method to source multi-LOD datasets useful for a number of applications. However, procedural modelling has not yet been employed for this purpose. Therefore, we have developed RANDOM3DCITY, an experimental procedural modelling engine for generating synthetic datasets of buildings and other urban features. The engine is designed to produce models in CityGML and does so in multiple LODs. Besides the generation of multiple geometric LODs, we implement the realisation of multiple levels of spatiosemantic coherence, geometric reference variants, and indoor representations. As a result of their permutations, each building can be generated in 392 different CityGML representations, an unprecedented number of modelling variants of the same feature. The datasets produced by RANDOM3DCITY are suited for several applications, as we show in this paper with documented uses. The developed engine is available under an open-source licence at Github at <a href="http://github.com/tudelft3d/Random3Dcity"target="_blank">http://github.com/tudelft3d/Random3Dcity</a>.

scholarly journals INTEGRATION OF SEMANTIC 3D CITY MODELS AND 3D MESH MODELS FOR ACCURACY IMPROVEMENTS OF SOLAR POTENTIAL ANALYSES

2018 ◽  
Vol XLII-4/W10 ◽  
pp. 223-230 ◽  
Author(s):  
B. Willenborg ◽  
M. Pültz ◽  
T. H. Kolbe
Keyword(s):  
Open Data ◽  
Region Growing ◽  
3D Models ◽  
Distance Measures ◽  
Data Set ◽  
3D Mesh ◽  
3D City Models ◽  
The Impact ◽  
Mesh Models ◽  
City Models

<p><strong>Abstract.</strong> High-resolution 3D mesh models are an inexpensive and increasingly available data source for 3D models of cities and landscapes of high visual quality and rich geometric detail. However, because of their simple data structure, their analytic capabilites are limited. Semantic 3D city model contain rich thematic information and are well suited for analytics due to their deeply structured semantic data model. In this work an approach for the integration of semantic 3D city models with 3D mesh models is presented. The method is based on geometric distance measures between mesh triangles and semantic surfaces and a region growing approach using plane fitting. The resulting semantic segmentation of mesh triangles is stored in a CityGML data set, to enrich the semantic model with an additional detailed geometric representation of its surfaces and a broad range of unrepresented features like technical building installations, balconies, dormers, chimneys, and vegetation. The potential of the approach is demonstrated on the example of a solar potential analysis, which estimation quality is significantly improved due to the mesh integration. The impact of the method is quantified on a case study using open data from the city of Helsinki.</p>

scholarly journals Incorporating Topological Representation in 3D City Models

2019 ◽  
Author(s):  
Stelios Vitalis ◽  
Ken Arroyo Ohori ◽  
Jantien Stoter
Keyword(s):  
Data Structure ◽  
Data Model ◽  
Semantic Information ◽  
Semantic Representation ◽  
Geometric Analysis ◽  
Computationally Efficient ◽  
Real World Data ◽  
3D City Models ◽  
Map Data ◽  
City Models

3D city models are being extensively used in applications such as evacuation scenarios and energy consumption estimation. The main standard for 3D city models is the CityGML data model which can be encoded through the CityJSON data format. CityGML and CityJSON use polygonal modelling in order to represent geometries. True topological data structures have proven to be more computationally efficient for geometric analysis compared to polygonal modelling. In a previous study, we have introduced a method to topologically reconstruct CityGML models while maintaining the semantic information of the dataset, based solely on the combinatorial map (C-Map) data structure. As a result of the limitations of C-Map's semantic representation mechanism, the resulting datasets could suffer either from semantic information loss or the redundant repetition of them. In this article, we propose a solution for a more efficient representation of both geometry, topology and semantics by incorporating the C-Map data structure in the CityGML data model and implementing a CityJSON extension to encode the C-Map data. In addition, we provide an algorithm for the topological reconstruction of CityJSON datasets to append them according to this extension. Finally, we apply our methodology to three open datasets in order to validate our approach when applied to real-world data. Our results show that the proposed CityJSON extension can represent all geometric information of a city model in a lossless way, providing additional topological information for the objects of the model.

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