Search

Building on a plethora of conjectured emendations for IOÏ'ΔAIAN, this article approaches the issue once again to test the viability of a quantitative tool and to establish the possibility of palaeographical confusion of IOÏ'ΔAIAN with an alternative topo- or demonym. The article starts with an experiment using Greek topo- and demonyms derived from contemporary Christian, Jewish, and Classical sources to establish a palaeographical confusion score. Next the likeliness of the "closest"alternatives in the geographical arrangement of Acts 2:9-11 is explored. The article ends with an evaluation of the possible implications for the text in Acts 2:9 as well as a critical appraisal of the method for conjectural criticism., Urban Data Science

The appearance of ουδα » αν in the table of nations (Acts 2:9-11) has troubled interpreters for centuries. Several scholars have proposed to emendate the text. The argumentations for such conjectures vary in elaboration and support. This article gives a diachronic overview of the conjectured emendations. It concludes with an evaluation of the discussion from a phenomenological perspective and a summary of the used argumentation, thereby providing input for a reversed engineering approach to the issue., 3D Geo-Information

Gedetailleerde modellen van gebouwen (BIM) worden als waardevol gezien in combinatie met geo-data. Met behulp van virtuele modellen van nieuwe gebouwen (of delen ervan) kan de impact van scenario’s worden doorgerekend op bijvoorbeeld energie, geluid of wind. Al tijdens de ontwerpfase kan rekening worden gehouden met planologische beperkingen, als deze informatie beschikbaar is. Het BIM kan na oplevering van het bouwwerk worden gebruikt als gebouwgebonden informatiedossier voor domeinen als energie, circulaire economie enzovoorts., 3D Geo-Information

Column, Urban Data Science

Software en data die iedereen vrij, open en kosteloos kan gebruiken, zijn niet weg te denken uit het geo-informatie landschap in Nederland. Denk aan de geo-basisregistraties BGT en BRT, maar ook het AHN. Veel geo-innovaties zijn hierdoor mogelijk gemaakt. Ons geo-onderwijs is er ook voor een belangrijk deel op gestoeld. Maar soms lijkt de open beschikbaarheid van data en software té vanzelfsprekend. Een goede reden om hier een column aan te wijden., Column, Urban Data Science

The Dutch Kadaster is responsible for the acquisition and maintenance of topographical data and visualisations at scale 1:10k and smaller. This is currently realised through an acquisition process by topographers who acquire 1:10k data from aerial images. In a next step, the smaller scale data and visualisations are derived by a fully automated generalisation process. Now a countrywide large-scale topographical dataset has become available, i.e. the key register large-scale topography (BGT), we have started a project to explore how to derive the Kadaster data from the BGT. This has two main objectives: to save money (i.e. collect once and use data many times) and to make the Kadaster data consistent with the BGT data. In this extended abstract we describe the project in which we define the content of the next generation Kadaster products that will be derived from BGT data., Urban Data Science

OGC CityGML is an open standard for 3D city models intended to foster interoperability and support various applications. However, through our practical experience and discussions with practitioners, we have noticed several problems related to the implementation of the standard and the use of standardized data. Nevertheless, a systematic investigation of these issues has never been carried out, and there is thus insufficient evidence for tackling the problems. The GeoBIM benchmark project is aimed at finding such evidence by involving external volunteers, reporting on various aspects of the behavior of tools (geometry, semantics, georeferencing, functionalities), analyzed and described in this article. This study explicitly pointed out the critical points embedded in the format as an evidence base for future development. A companion article (Part I) describes the results of the benchmark related to IFC, the counterpart of CityGML within building information modeling., Urban Data Science

Semantically enriched 3D city models have the potential to be powerful hubs of integrated information for computer-based urban spatial analysis. This article presents the state of the art in 3D city modelling in the context of broader developments such as smart cities and digital twins, and outlines six challenges that must be overcome before 3D data as a platform becomes a reality., Urban Data Science

During the past decade, hundreds of research papers have been published on the challenge of registering multi-level properties in land administration and cadastral registrations. In addition, many pilots have been carried out to show potential solutions. However, fundamental and standardised solutions for 3D cadastre are still rare. In this article we analyse the reasons for few 3D cadastre solutions in practice and we propose a 3D cadastre definition framework that can distinguish between different levels of 3D cadastre implementation depending on a specific context. Based on a level of detail logic, it supports an incremental pathway for the implementation of 3D cadastre solutions. We list the scope of the framework and finish with conclusions and future work., Urban Data Science

The trend of increased usage of both BIM and 3D GIS and the similarity between the two has led to an increase in the overlap between them. A key application of such overlap is providing geospatial context data for BIM models through importing 3D GIS-data to BIM software to help in different design-related issues. However, this is currently difficult because of the lack of support in BIM software for the formats and data models of 3D Geo-information. This paper deals with this issue by developing and implementing a methodology to convert the common open 3D city model data model into the most common open BIM data format, namely CityGML (Gröger et al., 2012) to IFC (buildingsmart, 2019b). For the aim of this study, the two standards are divided into 5 comparable subparts: Semantics, Geometry, Geographical coordinates, Topology, and Encoding. The characteristics of each of these subparts are studied and a conversion method is proposed for each of them from the former standard to the latter. This is done by performing a semantic and geometrical mapping between the two standards, converting the georeferencing from global to local, converting the encoding that the two standards use from XML to STEP, and deciding which topological relations are to be retained. A prototype implementation has been created using Python to combine the above tasks. The work presented in this paper can provide a foundation for future work in converting CityGML to IFC. It provides an insight into the relationship between the two standards and a methodology for the conversion from one to the other, and the process of developing software to perform such conversion. This is done in a way that can be extended for future specific needs., Urban Data Science

As web applications become more popular, 3D city models would greatly benefit from a proper web-based solution to visualise and manage them. CityJSON was introduced as a JSON encoding of the CityGML data model and promises, among several benefits, the ability to be integrated with modern web technologies. In order to provide an implementation of a web application for CityJSON data, that can be used as a reference for other applications, we developed ninja. It is a web application that allows the user to easily load and investigate a CityJSON model through a web browser. In addition, it offers support for a complex feature of CityJSON: the experimental versioning mechanism. In this paper, we describe the motivation, requirements, technical aspects and achieved functionality of ninja. We believe that such a web application can facilitate the adoption of 3D city models by more practitioners and decision makers., Urban Data Science

Among the digitalization processes which are being raised in Europe and in the world, the building permit process is seen as one of the priorities by municipalities, governmental institutions and standardization organizations. However, in current practice, the building permit issuing as well as the integration of geoinformation with BIM (GeoBIM) suffers from a number of complex sub-issues. These issues still remain and prevent the development of successful methodologies. In this paper, the building permit use case is explored within a project in close collaboration with the municipality of Rotterdam. A very specific case study in Rotterdam was selected as a starting point, which allowed us to develop the needed methodology for the implementation of an effective tool. In this paper we highlight the interpretation and formalization of regulation for building height, overhang and tower ratio. While these rules are specific to a zoning plan in Rotterdam, we believe that the methodology and encountered issues in formalizing the rules, applying the rules on delivered models and integrating various data sources (BIM and GIS specifically) are general to most building codes., Urban Data Science

In both research and practice, data interoperability is considered essential to support a rising number of applications that need data from different domains. Therefore, standard data formats and models are developed by standardization organizations such as Open Geospatial Consortium (for the Geo domain) and buildingSMART (for the BIM domain). However, from practical experiences, problems were noticed (standards implementation and use of standardized data). Nevertheless, it was hard to discover what the most serious issues were and what was their reason. For GeoBIM (integration of geoinformation with building information models), the CityGML standard, by Open Geospatial Consortium, and Industry Foundation Classes (IFC) by buildingSMART, were considered and tested in this initiative. A sample of datasets in the two formats were provided. External volunteers were asked to import the datasets in tools supposed to support the standards, check relevant aspects for the use of data (geometry, semantics, georeferencing, functionalities), report on them, and re-export the datasets in the standard format. Other tasks were intended to describe and test georeferencing procedures for IFC models and conversion tools between CityGML and IFC. This benchmark was useful to gather best practices and data about the functioning of useful tools to manage standardized data. Common behaviors and potential problems were pointed out and the discussion about the use of standards was further pushed., Urban Data Science

The Industry Foundation Classes are a prevalent open standard to exchange Building Information Models. In such a model, geometric representations are provided for individual building elements along with semantic information, including a significant amount of properties related togeometry and explicit topological relationships. These relationships and quantities introduce redundancies and often inconsistencies as well. Moreover, they introduce complexity in down-stream processing. Combining multiple aspect models into a single model has non-trivial consequences for the connectivity graphs. Programmatic mutations are complicated because of the relationships that need to be updated as a result of changes.In order to alleviate these issues, this paper provides a theoretical frameworkand implementation for both validating and inferring semantic and topological con-structs from the geometric representations, rooted on Egenhofer spatial predicates and extended with the IFC modelling tolerance. Combining these two concepts, wall connectivity is equivalent to the intersection of the wall representation boundaries, where a boundary is not a surface, but rather a hollow solid with a thickness derived from the modelling tolerance.The algorithms presented in this paper are implemented in fully open source software based on the IfcOpenShell software library and the CGAL computational geometry library using Nef polyhedra. We provide a formalization of space boundaries, spatial containment and wall connectivity relationships. The validation and inference rules are applied to a public set of building models. We conclude that exported models have geometric flaws and that several relationships can indeed be inferred by means of generic geometric intersection logic., Urban Data Science

The integration of 3D city models with Building Information Models (BIM), coined as GeoBIM, facilitates improved data support to several applications, e.g., 3D map updates, building permits issuing, detailed city analysis, infrastructure design, context-based building design, to name a few. To solve the integration, several issues need to be tackled and solved, i.e., harmonization of features, interoperability, format conversions, integration of procedures. The GeoBIM benchmark 2019, funded by ISPRS and EuroSDR, evaluated the state of implementation of tools addressing some of those issues. In particular, in the part of the benchmark described in this paper, the application of georeferencing to Industry Foundation Classes (IFC) models and making consistent conversions between 3D city models and BIM are investigated, considering the OGC CityGML and buildingSMART IFC as reference standards. In the benchmark, sample datasets in the two reference standards were provided. External volunteers were asked to describe and test georeferencing procedures for IFC models and conversion tools between CityGML and IFC. From the analysis of the delivered answers and processed datasets, it was possible to notice that while there are tools and procedures available to support georeferencing and data conversion, comprehensive definition of the requirements, clear rules to perform such two tasks, as well as solid technological solutions implementing them, are still lacking in functionalities. Those specific issues can be a sensible starting point for planning the next GeoBIM integration agendas, Urban Data Science

As in many countries, in The Netherlands governmental organisations are acquiring 3D city models to support their public tasks. However, this is still being done within individual organisation, resulting in differences in 3D city models within one country and sometimes covering the same area: i.e. differences in data structure, height references used, update cycle, data quality, use of the 3D data etc. In addition, often only large governmental organisations can afford investing in 3D city models (and the required knowledge) and not small organisations, like small municipalities. To address this problem, the Dutch Kadaster is collaborating with the 3D Geoinformation research group at TU Delft to generate and disseminate a 3D city model covering the whole of the Netherlands and to do this in a sustainable manner, i.e. with an implementation that ensures periodical updates and that aligns with the 3D city models of other governmental organisations, such as large cities. This article describes the workflow that has been developed and implemented., Urban Data Science

The digitalization of the process for building permit (involving the use of 3D information systems) is seen as a priority in a wide part of the world. Since it is a very multidisciplinary use case, involving a variety of stakeholders tackling complex issues and topics, some of them joined their efforts and skills in the European Network for Digital Building Permit. The initial activity of the network, after a review of on-going experiences, was a workshop to share knowledge about the topics involved and to identify the main ambitions of the network with respect to three pillars (i.e. Process - Rules and Requirements - Technology) and the related requirements. It was achieved through a collective brainstorming activity guided by digital tools, whose results were further analysed in a post-processing phase. Such results are presented in this paper and will be the base for planning the future network activity., Urban Data Science

Standardised data formats and data models are essential for data integration and interoperability, which in turn adds value to data by allowing its reuse in multiple contexts. For this reason, in recent years extensive efforts have been focused on standards development. When representing the built environment, 3D city models and Building Information Models are particularly relevant, and their integration is now required to underpin use cases that cover the full life-cycle of a built asset, including design and planning as well as operations and management, and to support legal applications such as cadastral systems. For those kinds of data, CityGML by the Open Geospatial Consortium and Industry Foundation Classes by buildingSMART are the most popular reference standards. However, many users report, often through informal channels, the difficulties of working with these formats. This paper summarizes the outcomes of the GeoBIM Benchmark 2019, a scientific initiative funded by ISPRS and EuroSDR to collect insights into the most relevant issues encountered in the management of CityGML and IFC within existing software. Alongside data management (import, visualisation, analysis, export) problems, issues of particular consequence in terms of integration relate to georeferencing IFC files and the conversions among the two kinds of formats and models. Thus, the benchmark was designed to explore these tasks in available software. Following analysis of the benchmark results, a key outcome is the impossibility to find clear patterns in the behaviour of tools, which consequently means there is no consistency in the implementation of standards. Although the results could seem disappointing, the criticality in managing these standards as they are was described and this awareness can be the starting point for further research or further standards development. Finally, this project was useful to gather a wide community around this topic, and the discussion about the GeoBIM-relat, Urban Data Science

When QGIS 3.0 was released in 2018, it added support for 3D visualisation. At the same time, CityJSON has been developing as an easy‐to‐use JavaScript Object Notation (JSON) encoding for 3D city models using the CityGML 2.0 data model. Together, this opened the possibility to support semantic 3D city models in the popular open‐source GIS software for the first time. In order to add support for 3D city models in QGIS, we have developed a plugin that enables CityJSON datasets to be loaded. The plugin parses a CityJSON file and analyses its tree structure to identify all city objects. Then, the geometry and attributes of every city object are transformed into QGIS features and divided into layers according to user preferences. CityJSON parsing was proven to be straightforward and consistent when tested against several open datasets. One of the biggest challenges we faced, though, was mapping CityJSON’s hierarchical data structure to the relational model of QGIS. We undertook this issue by providing various methods on how geometries from the model are loaded as QGIS features. We intend to use the plugin for educational purposes in our university and we believe it can be proven a worthy tool for researchers and practitioners., Urban Data Science

A bottom-up building energy modelling at the urban scale based on Geographic Information System and semantic 3D city models can provide quantitative insights to tackle critical urban energy challenges. Nevertheless, incomplete information is a common obstacle to produce reliable modelling results. The residential building heating demand simulation performance gap caused by input uncertainties is discussed in this study. We present a data-driven urban scale energy modelling framework from open-source data harmonization, sensitivity analysis, heating demand simulation at the postcode level to Bayesian calibration with six years of training data and two years of validation data. Comparing the baseline and the calibrated simulation results, the averaged absolute percentage errors of energy use intensity in the study area have significantly improved from 25.0% to 8.3% and from 19.9% to 7.7% in two validation years, while CVRMSE2016=11.5% and CVRMSE2017=13.2%. The overall methodology is extendable to other urban contexts., Intelligent Electrical Power Grids, Urban Data Science

This paper presents our implementation of a harmonized data model for noise simulations in the European Union (EU). Different noise assessment methods are used by different EU member states (MS) for estimating noise at local, regional, and national scales. These methods, along with the input data extracted from the national registers and databases, as well as other open and/or commercially available data, differ in several aspects and it is difficult to obtain comparable results across the EU. To address this issue, a common framework for noise assessment methods (CNOSSOS-EU) was developed by the European Commission’s (EC) Joint Research Centre (JRC). However, apart from the software implementations for CNOSSOS, very little has been done for the practical guidelines outlining the specifications for the required input data, metadata, and the schema design to test the real-world situations with CNOSSOS. We describe our approach for modeling input and output data for noise simulations and also generate a real world dataset of an area in the Netherlands based on our data model for simulating urban noise using CNOSSOS., Urban Data Science

Noise is one of the main problems in urban areas. To monitor and manage noise problems, governmental organisations at all levels are obliged to regularly carry out noise studies. The simulation of noise is an important part of these studies. Currently, different organisations collect their own 3D input data as required in noise simulation in a semi-automated way, even if areas overlap. This is not efficient, but also differences in input data may lead to differences in the results of noise simulation which has a negative impact on the reliability of noise studies. To address this problem, this paper presents a methodology to automatically generate 3D input data as required in noise simulations (i.e. buildings, terrain, land coverage, bridges and noise barriers) from current 2D topographic data and point clouds. The generated data can directly be used in existing noise simulation software. A test with the generated data shows that the results of noise simulation obtained from our generated data are comparable to results obtained in a current noise study from practice. Automatically generated input data for noise simulation, as achieved in this paper, can be considered as a major step in noise studies. It does not only significantly improve the efficiency of noise studies, thus reducing their costs, but also assures consistency between different studies and therefore it improves the reliability and reproducibility. In addition, the availability of countrywide, standardised input data can help to advance noise simulation methods since the calculation method can be adopted to improved ways of 3D data acquisition and reconstruction., Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public., Urban Data Science

Although the use of location-based data (location coupled with semantic information) within Geographical Information Systems (GIS) and from Earth Observation (e.g. satellite) sources has been long established for decision makers, this has only recently been reflected in the construction sector with a more recent move from Computer Aided Design (CAD) to Building Information Modelling. BIM has opened up an additional source of valuable location-based data, with particular focus on the architecture, structural and engineering detail of both buildings and infrastructure projects. As with most if not all location data, while BIM can be used on its own, major benefits are to be derived from integration with other data sources. When this is done with GIS, the result is known as GeoBIM and although there are some similarities between the two, challenges to integration are both technical and non technical, in particular the need for clear case studies to motivate both developers and senior management. There are synergies to be gained from a multi-national, coordinated approach when addressing these challenges, where participants can benefit from each-others' experience and where the needs of users and the National Mapping and Cadastral Agency (NMCA) perspective underpin the research. This paper summarises final outcomes and findings of the EuroSDR GeoBIM research project, which was set up to provide the required multi-national, user-centric collaborative framework, which had as its overall aim the development of best practice guidelines for GeoBIM, and due to its situation within EuroSDR has an NMCA focus. The paper updates information with regard to GeoBIM projects and maturity in the participant countries, and provides an overview of the two case studies developed., Urban Data Science

De term ‘digital twin’ hoor je steeds vaker als belangrijke ontwikkeling in relatie tot 3D-geo-informatie. Is dit een nieuw buzzwoord voor geo-informatie? Of gaat het hier echt om een nieuw concept? Met (3D) geo-informatie leggen we actuele data over onze omgeving vast met als doel om deze werkelijkheid te begrijpen en om via scenario’s te kunnen voorspellen wat ingrijpen in deze werkelijkheid voor impact heeft., Column, Urban Data Science

The Level of Detail (LOD) concept in CityGML 2.0 is meant to differentiate the multiple representations of semantic 3D city models. Despite the popularity and general acceptance of the concept by the practitioners and stakeholders in 3D city modelling, there are still some limitations. While the CityGML LOD concept is well defined for buildings, bridges, tunnels, and to some extent for roads, there is no clear definition of LODs for terrain/relief, vegetation, land use, water bodies, and generic city objects in CityGML. In addition, extensive research has been done to refine the LOD concept of CityGML for buildings but little is known on requirements and possibilities to model city object types as terrain at different LODs. To address this gap, we focus in this paper on the terrain of a 3D city model and propose a framework for modelling terrains at different LODs in CityGML. As a proof of concept of our framework, we implemented a software prototype to generate terrain models with other city features integrated (e.g. buildings) at different LODs in CityGML., Urban Data Science

GIS has become an important part of many disciplines and supports a vast range of applications. It is used everywhere, from agriculture to public health care. Furthermore, with the advances in technologies, the availability of GIS data and software support has grown exponentially. In this paper, we present the results of our international survey to investigate the adoption of geospatial data, standards, and software by the practitioners in different application domains. The results demonstrate a clear trend towards the increased use of GIS in a number of application domains including architecture, geosciences, hydrology, and so on. We also explore the expectations of the users from the GIS technologies and provide some insight into the current status of 3D GIS data and its applications., Urban Data Science

A significant number of studies has been carried out to establish 3D cadastre solutions to improve the registration of multi-level property. Since the inception of research on 3D cadastres (about 20 years ago), the world around us has changed significantly and this also partly changes the context regarding 3D cadastre: technology (e.g. visualisation of 3D information), acquisition techniques and BIM data availability, and policy and organisational structures. This paper aims to explore the implications of these changes on 3D cadastre research with a view to discussing considerations for a contemporary 3D cadastre for our times. The paper draws on social and technical trends, challenges, and gaps around 3D cadastre practices from three jurisdictions: the Australian state of Victoria, the Netherlands, and Singapore. The cases have been selected as examples of well-functioning and highly trusted cadastres and land registries committed to innovation in this area, and whose practitioners and researchers are leading the research in this domain. This set provides a breadth of insight that informs our discussion. However, we acknowledge the limitations of the findings as the research undertaken in these jurisdictions is not complicated by other issues with registration or cadastres as they may occur in other countries., Urban Data Science

In this paper we present an open and flexible approach for the standardisation of 3D geographical data, describing our physical environment in such a way that it can serve different applications. The aim of our approach is to keep the standard as simple as possible so that implementation in different software is straightforward and the reuse of once collected 3D data in different domains is optimally supported. Therefore, we propose to model the semantics of real-world objects independent from their application and we distinguish between the conceptual model and encoding. The result is a 3-layer approach, in which the first layer contains the conceptual model: the object types with their definitions and properties. This layer reuses definitions of various existing models (national and international) as much as possible. The second layer contains the modelling constraints: the set of rules that define how the objects from the conceptual model are represented in 3D as needed for a specific context or application. This second layer contains additional (3D) requirements to standardise the 3D representations of the objects. The third layer contains encoding profiles, thus specifying how different formats can best be encoded; these formats could be JSON or XML/GML. In this paper we motivate and describe our approach. For a small area we have developed a prototype that implements the 3 different layers. The prototype shows how the approach can be implemented for one specific application and additionally it provides insight into further development., Urban Data Science

The 3D representation of buildings with roof shapes (also called LoD2) is popular in the 3D city modelling domain since it provides a realistic view of 3D city models. However, for many application block models of buildings are sufficient or even more suitable. These so called LoD1 models can be reconstructed relatively easily from building footprints and point clouds. But LoD1 representations for the same building can be rather different because of differences in height references used to reconstruct the block models and differences in underlying statistical calculation methods. Users are often not aware of these differences, while these differences may have an impact on the outcome of spatial analyses. To standardise possible variances of LoD1 models and let the users choose the best one for their application, we have developed a LoD1 reconstruction service that generates several heights per building (both for the ground surface and the extrusion height). The building models are generated for all ~10 million buildings in The Netherlands based on footprints of buildings and LiDAR point clouds. The 3D dataset is updated every month automatically. In addition, for each building quality parameters are calculated and made available. This article describes the development of the LoD1 building service and we report on the spatial analysis that we performed on the generated height values., Urban Data Science

Eerder publiceerden we in Geo-Info over onze methode om 3D-data zoals nodig in geluidsimulaties automatisch te genereren uit landsdekkende gegevens zoals BAG, BGT en hoogtepunten [1]. Deze geluidsimulaties zijn gebaseerd op gestandaardiseerde rekenvoorschriften voor geluids- belasting. Ook het berekenen van de luchtkwaliteit ten gevolge van binnenstedelijk verkeer kent een Standaard Rekenmethode, beheerd door het RIVM. Deze methode is onder andere gebaseerd op de afstand tussen gebouwen en de weg en hoogtes van deze gebouwen, met andere woorden: een mooi 3D-geo informatievraagstuk. Daarom hebben we met een groep Geomatics-studenten gekeken of we deze informatie automatisch kunnen genereren, zodat de luchtverontreiniging ten gevolge van verkeer op landelijke schaal kan worden berekend., 3D Geo-Information

LandInfra is a relatively new open standard for modelling and representing land and infrastructure features. As it overlaps with other open standards in BIM (IFC) and 3D GIS (CityGML), it has been recognised as a potential candidate to bridge the gap between the two domains. However, the knowledge of this standard in both communities is low, and there are still no publications which fully explore LandInfra and its possibilities for integrated BIM-GIS applications. In this paper, we review the LandInfra conceptual model and its GML encoding InfraGML, provide a detailed comparison of it with respect to CityGML and IFC, and investigate a few potential use cases where LandInfra and InfraGML are useful for BIM-GIS applications., Urban Data Science

Laser scanning is an effective tool for acquiring geometric attributes of trees and vegetation, which lays a solid foundation for 3-dimensional tree modelling. Existing studies on tree modelling from laser scanning data are vast. However, some works cannot guarantee sufficient modelling accuracy, while some other works are mainly rule-based and therefore highly depend on user inputs. In this paper, we propose a novel method to accurately and automatically reconstruct detailed 3D tree models from laser scans. We first extract an initial tree skeleton from the input point cloud by establishing a minimum spanning tree using the Dijkstra shortest-path algorithm. Then, the initial tree skeleton is pruned by iteratively removing redundant components. After that, an optimization-based approach is performed to fit a sequence of cylinders to approximate the geometry of the tree branches. Experiments on various types of trees from different data sources demonstrate the effectiveness and robustness of our method. The overall fitting error (i.e., the distance between the input points and the output model) is less than 10 cm. The reconstructed tree models can be further applied in the precise estimation of tree attributes, urban landscape visualization, etc. The source code of this work is freely available at https://github.com/tudelft3d/adtree, Optical and Laser Remote Sensing, Urban Data Science

GeoBIM, the integration of 3D geoinformation (Geo) with building information models (BIM), is a subject of increasing attention in both domains. A well-known practical challenge for this integration is the mixed state of software support for open standards in each domain that would ease the integration. This is often known by practitioners but poorly documented. In order to solve this problem, we devised the GeoBIM benchmark, in which we compile the experiences of volunteering participants, who perform a guided study to test the software they are most familiar with against a few provided datasets structured in open standards. The aim of the tests is to improve the knowledge of the state of the art in the software support for GeoBIM open standards and to identify points for improvement. In this paper, we present the design of the benchmark, especially explaining and discussing the chosen data to be used with their connected issues to be tested, and some initial results., Urban Data Science

Before the interpretation of any text can start, the original wording of the text itself must be critically established. Conventionally, this is done following qualitative criteria. This article, however, explores the application of spatial analyses to New Testament textual criticism by demonstrating how the Levenshtein edit distance could be adapted to calculate confusion distances for variant readings in New Testament manuscripts, i.e. the possibility that a (combination of) letter(s) is confused by another (combination of) letter(s). Subsequently the outcomes are translated to Euclidian space using classical Multi-Dimensional Scaling, which enables visualisation and spatial analyses (in this case not related to geographical space). The article focuses on the data preparation and algorithm to make the data suitable for spatial analyses, thus providing the New Testament textual critic with new analytical tools., Urban Data Science

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., Urban Data Science