scholarly journals 3D CITY MODEL AS A FIRST STEP TOWARDS DIGITAL TWIN OF SOFIA CITY

2021 ◽  
Vol XLIII-B4-2021 ◽  
pp. 23-30
Author(s):  
H. Dimitrov ◽  
D. Petrova-Antonova
Keyword(s):  
Urban Areas ◽  
Web Application ◽  
User Interaction ◽  
Digital Twin ◽  
3D City Model ◽  
Digital Twins ◽  
Starting Point ◽  
Wide Range ◽  
City Model ◽  
The City

Abstract. Semantic 3D city models are increasingly applied for a wide range of analysis and simulations of large urban areas. Such models are used as a foundation for development of city digital twins, representing with high accuracy the landscapes and urban areas as well as dynamic of the city in terms of processes and events. In this context, this paper presents a 3D city model, which is a starting point for development of digital twin of Sofia city. The 3D model is compliant with CityGML 2.0 in LOD1, supporting integration of the buildings and terrain and enriching the buildings’ attributes with address information. District Lozenets of Sofia city is chosen as a pilot area for modelling. An approach for 3D transformation of proprietary geospatial data into CityGML schemas is presented. The integration of the buildings and terrain is an essential part of it, since the buildings often partially float over or sink into the terrain. A web application for user interaction with the 3D city model is developed. Its main features include silhouetting a single building, showing relevant overlay content, displaying shadows and styling of buildings depending on their attributes.

A 3D City Model as User Interface Connected to an Energy Model

2014 ◽  
pp. 228-246 ◽  
Author(s):  
Erik Kjems ◽  
Poul Alberg Østergaard
Keyword(s):  
Renewable Energy ◽  
Web Application ◽  
Energy Production ◽  
Energy System ◽  
Energy Model ◽  
Green Energy ◽  
Precise Calculation ◽  
3D City Model ◽  
City Model ◽  
The City

Back in 2007 the municipality of Frederikshavn in Northern Jutland in Denmark decided to use only 100% renewable energy for electricity, heat and transport by the year of 2015. Frederikshavn, the largest city in the municipality, was naturally chosen as case city. To be able to verify whether the green energy balance is possible to achieve, it was necessary to create energy scenarios for the whole city and also give the possibility to alter the current energy production and consumption. At the same time the city decided to involve as many people living in the city as possible, making it a project for the citizens of Frederikshavn. One result of this decision was an interactive Web application developed at Aalborg University. The application uses a 3D city model of the city of Frederikshavn as interface and gives the possibility to alter inputs for the energy consumption and energy production of the city using sliders and buttons as part of the interface. While the 3D model gives an immediate visual result, a connection to an underlying numerical energy model developed in earlier years at the University delivers a quite precise calculation on all vital data involved in the overall calculation of renewable energy within a closed energy system. This chapter describes the underlying theories and methods for creating such a system and presents the system, which can be understood as a case story among many.

Digital Twins for Cities: A State of the Art Review

2020 ◽  
Vol 46 (4) ◽  
pp. 547-573
Author(s):  
Bernd Ketzler ◽  
Vasilis Naserentin ◽  
Fabio Latino ◽  
Christopher Zangelidis ◽  
Liane Thuvander ◽  
...  
Keyword(s):  
Grey Literature ◽  
Physical Models ◽  
Global Perspective ◽  
Sensor Data ◽  
Dominant Term ◽  
Civic Society ◽  
Digital Twin ◽  
3D City Model ◽  
Digital Twins ◽  
City Model

During the last decades, a variety of digital tools have been developed to support both the planning and management of cities, as well as the inclusion of civic society. Here, the concept of a Digital Twin – which is rapidly emerging throughout many disciplines due to advances in technology, computational capacities and availability of large amounts of data – plays an important role. In short, a digital twin is a living virtual model, a connected digital representation of a physical system and has been a central concept in the manufacturing industry for the past decades. In this article, we review the terminology of digital twins for cities and identify commonalities and relations to the more established term 3D city models. Our findings indicate an increasing use of the term digital twin in academic literature, both in general and in the context of cities and the built environment. We find that while there is as yet no consensus on the exact definition of what constitutes a digital twin, it is increasingly being used to describe something that is more than a 3D city model (including, e.g. semantic data, real-time sensor data, physical models, and simulations). At the same time, the term has not yet replaced the term 3D city model as the most dominant term in the 3D GIS domain. By looking at grey literature we discuss how digital twins for cities are implemented in practice and present examples of digital twins in a global perspective. Further, we discuss some of the application areas and potential challenges for future development and implementation of digital twins for cities. We conclude that there are significant opportunities for up-scaling digital twins, with the potential to bring benefits to the city and its citizens and clients.

scholarly journals 3D BUILDING CHANGE DETECTION BETWEEN CURRENT VHR IMAGES AND PAST LIDAR DATA

2018 ◽  
Vol XLII-2 ◽  
pp. 1229-1235 ◽  
Author(s):  
K. Zhou ◽  
B. Gorte ◽  
R. Lindenbergh ◽  
E. Widyaningrum
Keyword(s):  
Change Detection ◽  
Urban Areas ◽  
Color Difference ◽  
False Alarms ◽  
Lidar Data ◽  
Stereo Pair ◽  
3D City Model ◽  
Sharp Edges ◽  
City Model ◽  
The City

Change detection is an essential step to locate the area where an old model should be updated. With high density and accuracy, LiDAR data is often used to create a 3D city model. However, updating LiDAR data at state or nation level often takes years. Very high resolution (VHR) images with high updating rate is therefore an option for change detection. This paper provides a novel and efficient approach to derive pixel-based building change detection between past LiDAR and new VHR images. The proposed approach aims notably at reducing false alarms of changes near edges. For this purpose, LiDAR data is used to supervise the process of finding stereo pairs and derive the changes directly. This paper proposes to derive three possible heights (so three DSMs) by exploiting planar segments from LiDAR data. Near edges, the up to three possible heights are transformed into discrete disparities. A optimal disparity is selected from a reasonable and computational efficient range centered on them. If the optimal disparity is selected, but still the stereo pair found is wrong, a change has been found. A Markov random field (MRF) with built-in edge awareness from images is designed to find optimal disparity. By segmenting the pixels into plane and edge segments, the global optimization problem is split into many local ones which makes the optimization very efficient. Using an optimization and a consecutive occlusion consistency check, the changes are derived from stereo pairs having high color difference. The algorithm is tested to find changes in an urban areas in the city of Amersfoort, the Netherlands. The two different test cases show that the algorithm is indeed efficient. The optimized disparity images have sharp edges along those of images and false alarms of changes near or on edges and occlusions are largely reduced.

scholarly journals Smart city dvelopment with digital twin technology

2020 ◽  
Author(s):  
Mervi Hämäläinen
Keyword(s):  
Urban Development ◽  
Smart City ◽  
Urban Areas ◽  
Raw Materials ◽  
Sustainable Urban Development ◽  
City Development ◽  
Digital Twin ◽  
Digital Twins ◽  
Overall Performance ◽  
The City

Growing urban areas are major consumers of natural resources, energy and raw materials. Understanding cities´ urban metabolism is salient when developing sustainable and resilient cities. This paper addresses concepts of smart city and digital twin technology as means to foster more sustainable urban development. Smart city has globally been well adopted concept in urban development. With smart city development cities aim to optimize overall performance of the city, its infrastructures, processes and services, but also to improve socio-economic wellbeing. Dynamic digital twins are constituted to form real-time connectivity between virtual and physical objects. Digital twin combines virtual objects to its physical counterparts. This conceptual paper provides additionally examples from dynamic digital twin platforms and digital twin of Helsinki, Finland.

scholarly journals FIRST STEPS TOWARDS AN INTEGRATED CITYGML-BASED 3D MODEL OF VIENNA

2016 ◽  
Vol III-4 ◽  
pp. 139-146 ◽  
Author(s):  
G. Agugiaro
Keyword(s):  
Energy Use ◽  
Smart Cities ◽  
Three Dimensional ◽  
3D City Model ◽  
First Results ◽  
Sustainable Energy Systems ◽  
City Model ◽  
Set Up ◽  
The City ◽  
City Models

This paper presents and discusses the results regarding the initial steps (selection, analysis, preparation and eventual integration of a number of datasets) for the creation of an integrated, semantic, three-dimensional, and CityGML-based virtual model of the city of Vienna. CityGML is an international standard conceived specifically as information and data model for semantic city models at urban and territorial scale. It is being adopted by more and more cities all over the world. <br><br> The work described in this paper is embedded within the European Marie-Curie ITN project “Ci-nergy, Smart cities with sustainable energy systems”, which aims, among the rest, at developing urban decision making and operational optimisation software tools to minimise non-renewable energy use in cities. Given the scope and scale of the project, it is therefore vital to set up a common, unique and spatio-semantically coherent urban model to be used as information hub for all applications being developed. This paper reports about the experiences done so far, it describes the test area and the available data sources, it shows and exemplifies the data integration issues, the strategies developed to solve them in order to obtain the integrated 3D city model. The first results as well as some comments about their quality and limitations are presented, together with the discussion regarding the next steps and some planned improvements.

Smart City and Digital Twins

2021 ◽  
pp. 243-264
Author(s):  
Sara Giaveno
Keyword(s):  
Smart City ◽  
Building Information Modeling ◽  
Information Modeling ◽  
3D City Models ◽  
3D City Model ◽  
Digital Twins ◽  
Building Information ◽  
City Model ◽  
Technical Features

The chapter proposed aims at facing the various implications underlying the smart city concept based on digital twins. The structure of the text is articulated in three main themes: the use of the term “smart city” and the role that technologies had in its definition; the “3D city model” meaning and the integration procedures between BIM (building information modeling) and GIS (geographic information system); the classification of 3D city models by use cases. The chapter can provide researchers with a detailed dissertation aimed at clarifying both the theoretical and technical features belonging to smart city and its related innovative technologies.

scholarly journals Peri-Urban Dynamics in Murcia Region (SE Spain): The Successful Case of the Altorreal Complex

Urban Science ◽  
2018 ◽  
Vol 2 (3) ◽  
pp. 60
Author(s):  
Rubén Giménez García ◽  
Ramón García Marín ◽  
José Serrano Martínez ◽  
Manuel Pulido Fernández
Keyword(s):  
Urban Development ◽  
Spatial Pattern ◽  
Urban Areas ◽  
Local Population ◽  
Se Spain ◽  
Functional Changes ◽  
Urban Dynamics ◽  
Successful Case ◽  
City Model ◽  
The City

The spatial pattern of the urban development recently experienced by large urban areas is significantly changing the traditional city model based on its compactness. It is generating new forms of urban organization that imply morphological, territorial, social, and functional changes. We analyzed the spatial impact generated by the construction of the Altorreal resort in the Murcia region and its effects on the local population (e.g. number of inhabitants). The results obtained highlight the importance of this resort in terms of space and population compared with other neighborhoods of the city.

scholarly journals Building Virtual 3D City Model for Smart Cities Applications: A Case Study on Campus Area of the University of Novi Sad

2020 ◽  
Vol 9 (8) ◽  
pp. 476 ◽  
Author(s):  
Dušan Jovanović ◽  
Stevan Milovanov ◽  
Igor Ruskovski ◽  
Miro Govedarica ◽  
Dubravka Sladić ◽  
...  
Keyword(s):  
Smart Cities ◽  
Airborne Lidar ◽  
3D City Models ◽  
3D City Model ◽  
City Model ◽  
Novi Sad ◽  
The University ◽  
The City ◽  
City Models

The Smart Cities data and applications need to replicate, as faithfully as possible, the state of the city and to simulate possible alternative futures. In order to do this, the modelling of the city should cover all aspects of the city that are relevant to the problems that require smart solutions. In this context, 2D and 3D spatial data play a key role, in particular 3D city models. One of the methods for collecting data that can be used for developing such 3D city models is Light Detection and Ranging (LiDAR), a technology that has provided opportunities to generate large-scale 3D city models at relatively low cost. The collected data is further processed to obtain fully developed photorealistic virtual 3D city models. The goal of this research is to develop virtual 3D city model based on airborne LiDAR surveying and to analyze its applicability toward Smart Cities applications. It this paper, we present workflow that goes from data collection by LiDAR, through extract, transform, load (ETL) transformations and data processing to developing 3D virtual city model and finally discuss its future potential usage scenarios in various fields of application such as modern ICT-based urban planning and 3D cadaster. The results are presented on the case study of campus area of the University of Novi Sad.

Virtual 3D City Model for Navigation in Urban Areas

2011 ◽  
Vol 66 (3) ◽  
pp. 377-399 ◽  
Author(s):  
Cindy Cappelle ◽  
Maan E. El Najjar ◽  
François Charpillet ◽  
Denis Pomorski
Keyword(s):  
Urban Areas ◽  
3D City Model ◽  
City Model
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