Data structuring & Interoperability options for optimising 3D City Modelling

Αθανασίου, Αικατερίνη; Athanasiou, Aikaterini

dc.contributor.author	Αθανασίου, Αικατερίνη	el
dc.contributor.author	Athanasiou, Aikaterini	en
dc.date.accessioned	2020-10-19T08:20:48Z
dc.date.available	2020-10-19T08:20:48Z
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/51512
dc.identifier.uri	http://dx.doi.org/10.26240/heal.ntua.19210
dc.rights	Αναφορά Δημιουργού-Όχι Παράγωγα Έργα 3.0 Ελλάδα	*
dc.subject	Τρισδιάστατη μοντελοποίηση	el
dc.subject	Σημασιολογκή διαχείριση	el
dc.subject	Προτυποποίηση	el
dc.subject	Διαλειτουργικότητα	el
dc.subject	Τρισδιάστατα μοντέλα πόλης	el
dc.subject	Interoperability	en
dc.subject	Building Information Modelling	el
dc.subject	CityGML	el
dc.subject	IFC	el
dc.subject	3D City Modelling	el
dc.title	Data structuring & Interoperability options for optimising 3D City Modelling	en
dc.contributor.department	Γεωπληροφορική	el
heal.type	masterThesis
heal.classification	ΓΕΩΠΛΗΡΟΦΟΡΙΚΗ	el
heal.classificationURI	http://data.seab.gr/concepts/0470dde7ed974578bbc4961549816f7b254efcb2
heal.language	en
heal.access	free
heal.recordProvider	ntua	el
heal.publicationDate	2018-06-29
heal.abstract	A city is decomposed into elements with clear semantics and defined spatial and thematic properties. Such elements are buildings, roads, railways, terrain, water, vegetation etc. These objects are further decomposed into different objects and even more detailed features, depending on the Level of Detail (LoD). 3D city models visually integrate the diversified geoinformation of the aforementioned elements within a single framework to provide notions of multiple resolutions and at different levels of abstraction. Various terms are used to define 3D city models, such as “Virtual City”, “Cybertown”, “Cybercity”, “Digital City”, “Smart City”. Nowadays, 3D City Models are increasingly used in different cities and countries for an intended wide range of applications beyond mere visualisation. The generation of 3D city models is a relevant and challenging task from a practical and a scientific point of view. 3D city models are of two types, design and real world models. Design models are usually used for building industry purposes and to fulfil the requirements of maximum level of detail in the Architecture, Engineering and Construction (AEC) industry. Real world models are geospatial information systems that represent spatial objects around us and are largely represented in GIS applications. Research efforts in the AEC industry resulted in Building Information Modelling (BIM), a process that supports information management throughout buildings’ lifecycle and is increasingly widely used in the AEC industry. Currently, the development of BIM and GIS shares several overlapping application areas. At the same time, the gaps between the two concepts are gradually reduced as multiple integration methods are being developed serving various reasons, aiming to solve different problems. The benefits brought by the integration of BIM and GIS are being proved by more and more research. The integration of the two systems is difficult for many reasons. Among them, data incompatibility is the most significant, as BIM and GIS data are created, managed, analyzed, stored, and visualized in different ways in terms of coordinate systems, scope of interest, and data structures. Different 3D data models have been developed and utilized within several domains. At first, the 3D data models that were developed were purely geometrical/graphical mainly used for visualisation purposes such as COLLADA (COLLAborative Design Activity), VRML (Virtual Reality Modelling Language), X3D (eXtensible 3D) etc. and neglected the semantics of objects and relationships. However, for a large portion of the applications, not only the geometrical/graphical features are important, but the semantics as well, which are lacked by purely geometrical/graphical models. In some cases the integration of 3D data becomes almost impossible. Difficulties arise while translating data from one data model to another such as loss of information, improper conversion, loss of relationships, topological and geometrical inconsistencies, etc. In such circumstances, there arises the need to develop interoperability between 3D data models to exchange data seamlessly. The ideal, successful data interoperability should be able to fully transfer information from BIM to GIS, or vice versa, in terms of both geometry and semantics without data loss. This must first be a reality before integration of BIM and GIS at application level can be achieved. Many data formats could be used to store 3D geometry, such as 3D Studio Max (.3ds), SketchUp (.skp), VRML and GeoVRML (.wrl), Openflight (.flt), and Collada (.dae). However, the most relevant 3D data formats involved in BIM/GIS integration are Industry Foundation Classes (IFC), City Geography Markup Language (CityGML). IFC is the primary open data schema used for information exchange within AEC/FM domains, which is EXPRESS-based and developed by buildingSMART. There are three ways for IFC to represent 3D geometry—boundary-representation (b-rep), constructive solid geometry (CSG), and sweep volumes. B-rep represents a 3D object using its bounding surfaces.. IFC classifies BIM models into five groups according to the details they contain by Levels of Development (LODt), from LOD 100 to LOD 500. Apart from the EXPRESS-based IFC file, buildingSMART also introduced a XML-based IFC standard, ifcXML. However, an ifcXML file is normally 3–4 times larger for storing the same information and is not as widely used as the EXPRESS-based file. CityGML is an open standard data model and exchange format to store 3D models of cities and landscapes based on Geography Markup Language defined by the Open Geospatial Consortium (OGC) in Extensible Markup Language (XML) format. It is an application schema for GML 3.1.1 (GML3) that is a standard for sharing or exchanging 2D and 3D geospatial information over the internet. It defines the basic entities, attributes, and relations of a city, which is essential for cost-effective sustainable 3D city model maintenance. Similarly, for most XML-based data models, there are two parts to CityGML—the schema that describes the document and the instance document that contains the actual data. As with IFC, CityGML has definitions for different Levels of Detail (LoDs) from LoD0 to LoD4 to reflect the amount of detail included in a model. LoD0 model is just the footprint of the building (in 2D), while LoD1 models are the basic block model with flat roofs. In LoD3 and LoD4, the models incorporate doors and windows and have close exterior views, while their internal components are quite different. LoD4 contains interior spaces (rooms) and internal walls, while the model in LoD3 does not. However, the building model in CityGML is less complete and mature as in BIM, even in LoD4. Currently, IFC and CityGML are representative data formats for BIM and GIS, respectively. Even though there are other formats involved, they are the most studied and accepted exchange formats. Apart from that, they are also complete ontologies for building and city models that could contribute to the construction of the semantic web. Therefore the integration of the two domains in data level is focused on the integration of these two formats. In the integration of IFC and CityGML building models, substantial difficulties may arise in translating information from one to the other. Professionals from both domains have made significant attempts to integrate CityGML and IFC models to produce useful common applications. This research aims to contribute from the very first step towards this integration and proposes a framework to better organise the elements during the design process in order to achieve semantically enhanced 3D information models according to IFC and CityGML standards. This is accomplished through the investigation of various options regarding the organisation of 2D architectural floor plans as input data, as well as through the exploration of CityEditor potentials in terms of this integration. A set of rules are proposed to redraw architectural floor plans from real life. These rules mainly focus on reorganising information contained in floor plans, taking advantages of the layering and blocking functions supported by CAD application, in order to easily produce 3D models, through other applications, which can be easily extracted to IFC and CityGML formats, since the structure of the data is based on these models. The research presented in this thesis can be used for future work on the interoperability between AEC/FM and Geomatics.	en
heal.advisorName	Δημοπούλου, Έφη	el
heal.committeeMemberName	Κάβουρας, Μαρίνος	el
heal.committeeMemberName	Κόκλα, Μαργαρίτα	el
heal.academicPublisher	Σχολή Αγρονόμων και Τοπογράφων Μηχανικών	el
heal.academicPublisherID	ntua
heal.numberOfPages	142
heal.fullTextAvailability	true