Exploration of the changing structure of cities: Challenges for temporal city models

International audienceThe ALARIC project (Incremental Urban Change Research Project) is dedicated to the production of geo-historical information concerning two formerly industrial cities of the Lyon-Saint-Etienne region (19 th and 20 th century). The exploration of the incremental nature of urban change implies identifying when certain historical processes took place, such as the shift from one-off to systematic construction and changes in urban planning strategies. Specifically, the case study investigates the emergence of local urban projects to compare the transformation processes of the urban fabric and to specify the pace of urban change. Historical records will be accessed through a virtual mapping environment based on the temporal reconstitution of cities in two dimensions, and sometimes for special cases in three dimensions. This paper presents methodological principles to reconstruct former cities in order to inquire urban change and requirements for effective sharing of hypotheses on the various states of the past urban landscape and associated transformation processes

Urban geo big data

The paper deals with the general presentation of the Urban GEO BIG DATA, a collaborative acentric and distributed Free and Open Source (FOS) platform consisting of several components: local data nodes for data and related service Web deploy; a visualization node for data fruition; a catalog node for data discovery; a CityGML modeler; data-rich viewers based on virtual globes; an INSPIRE metadata management system enriched with quality indicators for each dataset.Three use cases in five Italian cities (Turin, Milan, Padua, Rome, and Naples) are examined: 1) urban mobility; 2) land cover and soil consumption at different resolutions; 3) displacement time series. Besides the case studies, the architecture of the system and its components will be presented

A continuous deployment-based approach for the collaborative creation, maintenance, testing and deployment of CityGML models

Georeferenced 3D models are an increasingly common choice to store and display urban data in many application areas. CityGML is an open and standardized data model, and exchange format that provides common semantics for 3D city entities and their relations and one of the most common options for this kind of information. Currently, creating and maintaining CityGML models is costly and difficult. This is in part because both the creation of the geometries and the semantic annotation can be complex processes that require at least some manual work. In fact, many publicly available CityGML models have errors. This paper proposes a method to facilitate the regular maintenance of correct city models in CityGML. This method is based on the continuous deployment strategy and tools used in software development, but adapted to the problem of creating, maintaining and deploying CityGML models, even when several people are working on them at the same time. The method requires designing and implementing CityGML deployment pipelines. These pipelines are automatic implementations of the process of building, testing and deploying CityGML models. These pipelines must be run by the maintainers of the models when they make changes that are intended to be shared with others. The pipelines execute increasingly complex automatic tests in order to detect errors as soon as possible, and can even automate the deployment step, where the CityGML models are made available to their end users. In order to demonstrate the feasibility of this method, and as an example of its application, a CityGML deployment pipeline has been developed for an example scenario where three actors maintain the same city model. This scenario is representative of the kind of problems that this method intends to solve, and it is based on real work in progress. The main benefits of this method are the automation of model testing, every change to the model is tested in a repeatable way; the automation of the model deployment, every change to the model can reach its end users as fast as possible; the systematic approach to integrating changes made by different people working together on the models, including the possibility of keeping parallel versions with a common core; an automatic record of every change made to the models (who did what and when) and the possibility of undoing some of those changes at any time.This work was supported by the Optimised Energy Efficient Design Platform for Refurbishment at District Level (OptEEmAL) project, Grant Agreement Number 680676, 2015-2019, as part of the European Union’s Horizon 2020 research and innovation programme

DATA INTEGRATION OF DIFFERENT DOMAINS IN GEO-INFORMATION MANAGEMENT: A RAILWAY INFRASTRUCTURE CASE STUDY

A 3D city model is a representation of an urban environment with a three-dimensional geometry of common urban objects and structures, with buildings as the most prominent feature. In the last decades, 3D city models appear to have been predominantly used for visualisation; however, nowadays they are being increasingly employed in a number of domains and for a broad range of tasks beyond visualisation. The MUIF (Modello Unico dell’Infrastruttura Fisica) project, here illustrated as a case study, refers to the implementation of a single spatial model of the infrastructure of Italy’s railway system (RFI). The authors describe preliminary results and the critical aspects of the study they are carrying out, explaining the processes and methodology to model all datasets into a single integrated spatial model as the reference base for future continuously updates. The case study refers to data collected by different sources and at various resolutions. An integrated spatial Database has been used for modelling topographic 3D objects, traditionally implemented in a 3D city model, as well as other specific 3D objects, related to the railway infrastructure that, usually, aren’t modelled in a 3D city model, following the same methodology as the first ones.</p

A continuous deployment-based approach for the collaborative creation, maintenance, testing and deployment of CityGML models

Georeferenced 3D models are an increasingly common choice to store and display urban data in many application areas. CityGML is an open and standardized data model, and exchange format that provides common semantics for 3D city entities and their relations and one of the most common options for this kind of information. Currently, creating and maintaining CityGML models is costly and difficult. This is in part because both the creation of the geometries and the semantic annotation can be complex processes that require at least some manual work. In fact, many publicly available CityGML models have errors. This paper proposes a method to facilitate the regular maintenance of correct city models in CityGML. This method is based on the continuous deployment strategy and tools used in software development, but adapted to the problem of creating, maintaining and deploying CityGML models, even when several people are working on them at the same time. The method requires designing and implementing CityGML deployment pipelines. These pipelines are automatic implementations of the process of building, testing and deploying CityGML models. These pipelines must be run by the maintainers of the models when they make changes that are intended to be shared with others. The pipelines execute increasingly complex automatic tests in order to detect errors as soon as possible, and can even automate the deployment step, where the CityGML models are made available to their end users. In order to demonstrate the feasibility of this method, and as an example of its application, a CityGML deployment pipeline has been developed for an example scenario where three actors maintain the same city model. This scenario is representative of the kind of problems that this method intends to solve, and it is based on real work in progress. The main benefits of this method are the automation of model testing, every change to the model is tested in a repeatable way; the automation of the model deployment, every change to the model can reach its end users as fast as possible; the systematic approach to integrating changes made by different people working together on the models, including the possibility of keeping parallel versions with a common core; an automatic record of every change made to the models (who did what and when) and the possibility of undoing some of those changes at any time

DBL SmartCity: An Open-Source IoT Platform for Managing Large BIM and 3D Geo-Referenced Datasets

The `smart city\u27 approach has been promoted as an effective way to manage urban environments. Information and communication technology in general, as well as `Internet of Things\u27 systems in particular, constitute an essential component of all smart city initiatives. However, many past and current smart city implementations place only an insufficient emphasis on the geo-spatial and 3D nature of data. In order to fill this gap, we present DBL SmartCity, an open-source smart city IoT platform that is based on open standards and designed from the ground-up to effectively store, manage, and present large sets of BIM and 3D geo-referenced data

Spatial ontologies for architectural heritage

Informatics and artificial intelligence have generated new requirements for digital archiving, information, and documentation. Semantic interoperability has become fundamental for the management and sharing of information. The constraints to data interpretation enable both database interoperability, for data and schemas sharing and reuse, and information retrieval in large datasets. Another challenging issue is the exploitation of automated reasoning possibilities. The solution is the use of domain ontologies as a reference for data modelling in information systems. The architectural heritage (AH) domain is considered in this thesis. The documentation in this field, particularly complex and multifaceted, is well-known to be critical for the preservation, knowledge, and promotion of the monuments. For these reasons, digital inventories, also exploiting standards and new semantic technologies, are developed by international organisations (Getty Institute, ONU, European Union). Geometric and geographic information is essential part of a monument. It is composed by a number of aspects (spatial, topological, and mereological relations; accuracy; multi-scale representation; time; etc.). Currently, geomatics permits the obtaining of very accurate and dense 3D models (possibly enriched with textures) and derived products, in both raster and vector format. Many standards were published for the geographic field or in the cultural heritage domain. However, the first ones are limited in the foreseen representation scales (the maximum is achieved by OGC CityGML), and the semantic values do not consider the full semantic richness of AH. The second ones (especially the core ontology CIDOC – CRM, the Conceptual Reference Model of the Documentation Commettee of the International Council of Museums) were employed to document museums’ objects. Even if it was recently extended to standing buildings and a spatial extension was included, the integration of complex 3D models has not yet been achieved. In this thesis, the aspects (especially spatial issues) to consider in the documentation of monuments are analysed. In the light of them, the OGC CityGML is extended for the management of AH complexity. An approach ‘from the landscape to the detail’ is used, for considering the monument in a wider system, which is essential for analysis and reasoning about such complex objects. An implementation test is conducted on a case study, preferring open source applications

The Venetian Ghetto : Semantic Modelling for an Integrated Analysis

In the digital era, historians are embracing information technology as a research tool. New technologies offer investigation and interpretation, synthesis and communication tools that are more effective than the more traditional study methods, as they guarantee a multidisciplinary approach and analyses integration. Among the available technologies the best suited for the study or urban phenomena are databases (DB), the Geographic Information System (GIS), the Building Information Modelling (BIM) and the multimedia tools (Video, APP) for the dissemination of results. The case study described here concerns the analysis of part of Venice that changed its appearance from 1516 onwards, with the creation of the Jewish Ghetto. This was an event that would have repercussions throughout Europe, changing the course of history. Our research confirms that the exclusive use of one of the systems mentioned above (DB, GIS, BIM) makes it possible to manage the complexity of the subject matter only partially. Consequently, it became necessary to analyse the possible interactions between such tools, so as to create a link between an alphanumeric DB and a geographical DB. The use of only GIS and BIM that provide for a 4D time management of objects turned out to be able to manage information and geometry in an effective and scalable way, providing a starting point for the mapping in depth of the historical analysis. Software products for digital modelling have changed in nature over time, going from simple viewing tools to simulation tools. The reconstruction of the time phases of the three Ghettos (Nuovo, Vecchio, and Nuovissimo) and their visualisation through digital narratives of the history of that specific area of the city, for instance through videos, is making it possible for an increasing number of scholars and the general public to access the results of the study

Scale aware modeling and monitoring of the urban energy chain

With energy modeling at different complexity levels for smart cities and the concurrent data availability revolution from connected devices, a steady surge in demand for spatial knowledge has been observed in the energy sector. This transformation occurs in population centers focused on efficient energy use and quality of life. Energy-related services play an essential role in this mix, as they facilitate or interact with all other city services. This trend is primarily driven by the current age of the Ger.: Energiewende or energy transition, a worldwide push towards renewable energy sources, increased energy use efficiency, and local energy production that requires precise estimates of local energy demand and production. This shift in the energy market occurs as the world becomes aware of human-induced climate change, to which the building stock has a significant contribution (40% in the European Union). At the current rate of refurbishment and building replacement, of the buildings existing in 2050 in the European Union, 75% would not be classified as energy-efficient. That means that substantial structural change in the built environment and the energy chain is required to achieve EU-wide goals concerning environmental and energy policy. These objectives provide strong motivation for this thesis work and are generally made possible by energy monitoring and modeling activities that estimate the urban energy needs and quantify the impact of refurbishment measures. To this end, a modeling library called aEneAs was developed in the scope of this thesis that can perform city-wide building energy modeling. The library performs its tasks at the level of a single building and was a first in its field, using standardized spatial energy data structures that allow for portability from one city to another. For data input, extensive use was made of digital twins provided from CAD, BIM, GIS, architectural models, and a plethora of energy data sources. The library first quantifies primary thermal energy demand and then the impact of refurbishment measures. Lastly, it estimates the potential of renewable energy production from solar radiation. aEneAs also includes network modeling components that consider energy distribution in the given context, showing a path toward data modeling and simulation required for distributed energy production at the neighborhood and district level. In order to validate modeling activities in solar radiation and green façade and roof installations, six spatial models were coupled with sensor installations. These digital twins are included in three experiments that highlight this monitoring side of the energy chain and portray energy-related use cases that utilize the spatially enabled web services SOS-SES-WNS, SensorThingsAPI, and FIWARE. To this author\u27s knowledge, this is the first work that surveys the capabilities of these three solutions in a unifying context, each having its specific design mindset. The modeling and monitoring activity and their corresponding literature review indicated gaps in scientific knowledge concerning data science in urban energy modeling. First, a lack of standardization regarding the spatial scales at which data is stored and used in urban energy modeling was observed. In order to identify the appropriate spatial levels for modeling and data aggregation, scale is explored in-depth in the given context and defined as a byproduct of resolution and extent, with ranges provided for both parameters. To that end, a survey of the encountered spatial scales and actors in six different geographical and cultural settings was performed. The information from this survey was used to put forth a standardized spatial scales definition and create a scale-dependent ontology for use in urban energy modeling. The ontology also provides spatially enabled persistent identifiers that resolve issues encountered with object relationships in modeling for inheritance, dependency, and association. The same survey also reveals two significant issues with data in urban energy modeling. These are data consistency across spatial scales and urban fabric contiguity. The impact of these issues and different solutions such as data generalization are explored in the thesis. Further advancement of scientific knowledge is provided specifically with spatial standards and spatial data infrastructure in urban energy modeling. A review of use cases in the urban energy chain and a taxonomy of the standards were carried out. These provide fundamental input for another piece of this thesis: inclusive software architecture methods that promote data integration and allow for external connectivity to modern and legacy systems. In order to reduce time-costly extraction, transformation, and load processes, databases and web services to ferry data to and from separate data sources were used. As a result, the spatial models become central linking elements of the different types of energy-related data in a novel perspective that differs from the traditional one, where spatial data tends to be non-interoperable / not linked with other data types. These distinct data fusion approaches provide flexibility in an energy chain environment with inconsistent data structures and software. Furthermore, the knowledge gathered from the experiments presented in this thesis is provided as a synopsis of good practices

Interconnection between Scales for Friendly and Affordable Sustainable Urban Districts Retrofitting

The EU FP7 project FASUDIR (Friendly and Affordable Sustainable Urban Districts Retrofitting) supports the mobilization of the building retrofitting market towards 2020-2050 EU-targets through an Integrated Decision Support Tool (IDST), a software based on a new methodology that will help decision makers identify the best energy retrofitting strategy to increase the sustainability of the whole district. Improving the sustainability of urban environments is a interscalar problem, addressed through a multiscalar and multidirectional approach. A comprehensive urban scale strategy considers the working scale, but the measures at building scale have to be coherent with the global objectives at district and city scale. The FASUDIR IDST and methodology interconnect and visualize information across scales, ensuring comprehensive diagnoses and proper implementation of strategies. Due to the complexity of urban sustainability, interscalarity and multiscalarity, first it has been necessary to identify the possible scales of analysis, to capture various themes and to highlight the horizontal and vertical interconnections between different components. Multiscalarity and Interscalarity affect the three phases of the sustainable retrofitting cycle: diagnosis, decision making and management. The identification of the impact of district solutions on buildings (and vice versa) and their compatibility across scales has been addressed through interconnected building and district Key Performance Iindicators (KPIs). The intervention phases at building level generate new information about specific buildings, enabling more accurate decision making at district level. The methodology articulates the structure of the new information and the feedback generated during the process. To allow information interconnection a strategic information management is key. A multiscale information model based on CityGML, a standard data model issued by the OGC (Open Geospatial Consortium), will be the baseline structure for all the district-scale information (geometric and semantic) that is necessary for decision making and management, organized into a single interoperable data model that will integrate information from different fields and at different levels of detail.European Commission's FP