Cadastral Agencies Research Articles

GEOMETRIC PROCESSING OF VERY HIGH-RESOLUTION SATELLITE IMAGERY: QUALITY ASSESSMENT FOR 3D MAPPING NEEDS

Abstract. In recent decades, the geospatial domain has benefitted from technological advances in sensors, methodologies, and processing tools to expand capabilities in mapping applications. Airborne techniques (LiDAR and aerial photogrammetry) generally provide most of the data used for this purpose. However, despite the relevant accuracy of these technologies and the high spatial resolution of airborne data, updates are not sufficiently regular due to significant flight costs and logistics. New possibilities to fill this information gap have emerged with the advent of Very High Resolution (VHR) optical satellite images in the early 2000s. In addition to the high temporal resolution of the cost-effective datasets and their sub-meter geometric resolutions, the synoptic coverage is an unprecedented opportunity for mapping remote areas, multi-temporal analyses, updating datasets and disaster management. For all these reasons, VHR satellite imagery is clearly a relevant study for National Mapping and Cadastral Agencies (NMCAs). This work, supported by EuroSDR, summarises a series of experimental analyses carried out over diverse landscapes to explore the potential of VHR imagery for large-scale mapping.

Uvajanje tehnologije Linked Data v geodetskih upravah: sistematični pregled literature

This research focuses on a systematic literature review of the geospatial Linked Data (LD) publication at National Mapping and Cadastral Agencies in Europe (NMCA) responsible for land administration. We analysed scientific studies published from 2014 to 2023. Our research aimed to find out the reasons for the relatively slow adoption of geospatial data publication as LD. Therefore, we searched for the most common problems, solutions, and challenges for publishing prioritised data themes in NMCAs. Applied research methodology relies on well-established approaches such as analysing Population Problems, Intervention, Comparison, Outcomes, and Circumstances (PICOC) and backward snowballing. The eligibility process is presented by Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. We analysed nineteen extracted papers and identified twelve key issues from full-text reading. Frequency analyses resulted in the overview of the most frequently published geospatial themes as LD in several European countries. We addressed five research questions and concluded that in addition to systematic support for developing vocabularies and ontologies, trust, awareness, and knowledge about best practices could influence the success of LD publication at NMCAs.

Design of methodology for estimation of parcel investment attractiveness using spatially adjusted predictive modelling

Determining investment attractiveness is an important task, in the meaning of economic and administration operation. The investment attractiveness of a land parcel can be assessed quantitatively as a value of dynamics in its sale price. In addition, spatial parameters can be accounted when estimating the investment attractiveness. To ensure prediction of land parcel sale prices and their dynamics we implemented ensemble regression analysis. Methodology was tested on publically accessible data of Russian cadastral agency. To elaborate an investment attractiveness clustering of cadastral units depending on price and spatial parameters, we conducted k-means clustering with Silhouette metric control.

LOCATION-ENABLED DIGITAL TWINS – UNDERSTANDING THE ROLE OF NMCAS IN A EUROPEAN CONTEXT

Abstract. Digital Twins are realistic digital representation of physical objects and are differentiated from traditional models by the live connection between the digital and the physical worlds, often enabled by sensors. They provide insights into the physical world for decision makers, for example via simulation, and can be used to directly alter the physical world without manual intervention. While they have their origins in manufacturing, they are increasingly being used within the built environment, by both public and private sectors. Increasingly city-wide and National Digital Twins are also being considered, to underpin local, municipal and central government decision making. For these emerging Digital Twins, location data such as that provided by National Mapping and Cadastral Agencies (NMCAs) has the potential to underpin Digital Twin modelling. It thus becomes important for NMCAs to better understand Digital Twins in order to determine whether current data offerings can meet this new demand and how best to support the various activities. As a first stage investigation under the auspices of EuroSDR, this paper explores challenges and opportunities for NMCAs and others working in the location sector, presenting the result of an international survey and workshop on these topics. We conclude that there is significant overlap with existing challenges within the geospatial community and those required to better support Digital Twins - e.g. interoperability and data management and governance. Additionally, the opportunity for a broader understanding and uptake of location data offered by Digital Twins should not be ignored.

EXPLORING EXISTING 3D RECONSTRUCTION TOOLS FOR THE GENERATION OF 3D CITY MODELS AT VARIOUS LOD FROM A SINGLE DATA SOURCE

Abstract. The use of three-dimensional (3D) city models has increased in a wide range of applications beyond visualisation. However, generation and maintenance of 3D data comes at a high cost, time, and workload. The purpose of the generalisation where coarser versions are obtained from a source data is of great interest for National Mapping and Cadastral Agencies (NMCA), which would benefit obtaining multiple 3D versions of an area from a single source. The main aim of the exploration presented in this paper is to study the potential of downsizing point clouds as an approach to generate 3D city models at multiple levels of detail from a single source and evaluate the steps required to ensure the output is fit for real world applications from an NMCA context. While interesting results are obtained when testing with sample data, no software managed to semi-automatically reconstruct 3D model for buildings of rather complicated geometry.

MAINTENANCE AND UPDATE NATIONAL TOPOGRAPHIC DATA BASE IN HIGH FREQENCY USING MODERN PROCEDURES AND TECHNIQUES

Abstract. The state of Israel is a small country, in terms of area, with one the higher population growth rate among all the OECD countries. Hence, each year more than 50,000 housing units built and more than 1,500 km roads constructed in average, each year along the last decade.The Survey of Israel )SOI( is a National Mapping and Cadastral agency (NMCA) that holds the responsibility to update, maintain and disseminate the National Topographic Data Base (NTDB) to all of the governmental offices and municipalities, to utilize, plan and promote the construction of the public needs.Today, the reality is dynamic and the changes occurs every day, therefore, the users expect that the existing database will portray the current reality as possible. In order to address the user's requirements for rapid updating rate, the Survey of Israel promote a new and modern initiatives, including:Promote the cooperation and working relationship with the municipalities to rapidly update the streets, address and POI’s.Data Fusion from different governmental and municipalities data sources.Developing change detection techniques to update the buildings and roads layers.Developing new frameworks for the manual inspection and QA/QC procedures.Developing automatic tools to update the height component via high resolution DSM and DTM (50cm GSD).Disseminate quarterly the NTDB products to the users.Develop a modern processes management system for the update and QA workflowIn this article, we will demonstrate the initiatives and techniques that improved our NTDB updating rate to less than a year and a half in a national average.

Revising Cadastral Data on Land Boundaries Using Deep Learning in Image-Based Mapping

One of the main concerns of land administration in developed countries is to keep the cadastral system up to date. The goal of this research was to develop an approach to detect visible land boundaries and revise existing cadastral data using deep learning. The convolutional neural network (CNN), based on a modified architecture, was trained using the Berkeley segmentation data set 500 (BSDS500) available online. This dataset is known for edge and boundary detection. The model was tested in two rural areas in Slovenia. The results were evaluated using recall, precision, and the F1 score—as a more appropriate method for unbalanced classes. In terms of detection quality, balanced recall and precision resulted in F1 scores of 0.60 and 0.54 for Ponova vas and Odranci, respectively. With lower recall (completeness), the model was able to predict the boundaries with a precision (correctness) of 0.71 and 0.61. When the cadastral data were revised, the low values were interpreted to mean that the lower the recall, the greater the need to update the existing cadastral data. In the case of Ponova vas, the recall value was less than 0.1, which means that the boundaries did not overlap. In Odranci, 21% of the predicted and cadastral boundaries overlapped. Since the direction of the lines was not a problem, the low recall value (0.21) was mainly due to overly fragmented plots. Overall, the automatic methods are faster (once the model is trained) but less accurate than the manual methods. For a rapid revision of existing cadastral boundaries, an automatic approach is certainly desirable for many national mapping and cadastral agencies, especially in developed countries.

Consideration on how to introduce gamification tools to enhance citizen engagement in crowdsourced cadastral surveys

The major objective of this research is to investigate the progress of citizen participation in cadastral surveying and to consider ways on how to introduce gamification tools for further improvement. A brief literature review is presented in the areas of the Sustainable Development Agenda 2030 related to land administration and citizen engagement, e-government and citizen participation and gamification tools for citizen engagement. This paper, also, includes an investigation of the progress in introducing volunteerism and citizen participation to the Hellenic Cadastre. A case study is held by a group of volunteers in order to assess the developed tools designed either by the private sector or by the cadastral agency.

3RD BIM/GIS INTEGRATION WORKSHOP AND 15TH 3DGEOINFO CONFERENCE 2020 – PREFACE

Abstract. The interest in and use of 3D models in built environments is rapidly increasing, and they are now a key component of decision-making in areas including climate change mitigation (e.g., calculating solar panel potential, flood modelling, modelling housing age for retrofitting of thermal insulation), urban planning and cadastral systems (modelling rights, restrictions and responsibilities in complex buildings, streamlining the process to issue planning permits, design of existing or new developments) and infrastructure (construction, transport, utility management and modelling, asset management). 3D models are also an integrator for the data underpinning smart cities – knowing where a sensor is in 3D space allows the data to be integrated with the surrounding context – for example, noise data could be integrated with traffic information. Reflecting this interest, national mapping and cadastral agencies (NMCA) including Ordnance Survey (GB) are now increasingly generating 3D mapping at national scale, and there is extensive research as to how this data can be integrated with another emerging source of 3D models such as building information modelling (BIM).These trends were evident during the 3rd BIM/GIS Integration Workshop and 15th 3DGeoInfo 2020 events, which were co-hosted by University College London and Ordnance Survey (GB) in September 2020. The workshop and conference brought together international researchers from academia, industry, government and national mapping and cadastral agencies in the field of 3D geoinformation, in an interdisciplinary gathering of researchers in the fields of data collection, data management, data quality, data analysis, advanced modelling approaches, applications, users, visualisation, augmented reality, artificial intelligence and many more.This year’s theme was Users and Use Cases. The workshop and conference covered a wide range of topics including 3D data acquisition and processing, 3D city modelling and related standards, visualisation and dissemination of 3D data, augmented and virtual reality, 3D and Artificial Intelligence/Machine Learning. Three sessions of the BIM/GIS Integration Workshop were dedicated to Applications of BIM/GIS Integration, and an entire day of 3DGeoInfo 2020 to Users and Use Cases within 3DGeoInfo. Additionally, two sessions were specifically aimed at NMCA participants.Although initially intended to be a face-to-face event in London, the team rapidly adjusted to the emerging COVID-19 situation, identifying an online solution that facilitated and encouraged participant interaction. This meant that the events could still provide a platform for learning, discussion, and exchange of ideas that they have been able to in previous years, as well as providing opportunities to promote international collaboration in these topics. This special issue of the ISPRS International Annals of Photogrammetry, Remote Sensing and Spatial Information Sciences contains 22 papers selected by double-blind peer review carried out by a minimum of three reviewers. It includes research on topics including data modelling, indoor 3D, standards (IndoorML, CityGML, CityJSON), cadastral systems, pedestrian navigation, infrastructure, visualisation, point cloud management, data interoperability, data quality, generating national 3D datasets and planning/permit processes amongst others.

3RD BIM/GIS INTEGRATION WORKSHOP AND 15TH 3DGEOINFO CONFERENCE 2020 – PREFACE

Abstract. The interest in and use of 3D models in built environments is rapidly increasing, and they are now a key component of decision-making in areas including climate change mitigation (e.g., calculating solar panel potential, flood modelling, modelling housing age for retrofitting of thermal insulation), urban planning and cadastral systems (modelling rights, restrictions and responsibilities in complex buildings, streamlining the process to issue planning permits, design of existing or new developments) and infrastructure (construction, transport, utility management and modelling, asset management). 3D models are also an integrator for the data underpinning smart cities – knowing where a sensor is in 3D space allows the data to be integrated with the surrounding context – for example, noise data could be integrated with traffic information. Reflecting this interest, national mapping and cadastral agencies (NMCA) including Ordnance Survey (GB) are now increasingly generating 3D mapping at national scale, and there is extensive research as to how this data can be integrated with another emerging source of 3D models such as building information modelling (BIM).These trends were evident during the 3rd BIM/GIS Integration Workshop and 15th 3DGeoInfo 2020 events, which were co-hosted by University College London and Ordnance Survey (GB) in September 2020. The workshop and conference brought together international researchers from academia, industry, government and national mapping and cadastral agencies in the field of 3D geoinformation, in an interdisciplinary gathering of researchers in the fields of data collection, data management, data quality, data analysis, advanced modelling approaches, applications, users, visualisation, augmented reality, artificial intelligence and many more.This year’s theme was Users and Use Cases. The workshop and conference covered a wide range of topics including 3D data acquisition and processing, 3D city modelling and related standards, visualisation and dissemination of 3D data, augmented and virtual reality, 3D and Artificial Intelligence/Machine Learning. Three sessions of the BIM/GIS Integration Workshop were dedicated to Applications of BIM/GIS Integration, and an entire day of 3DGeoInfo 2020 to Users and Use Cases within 3DGeoInfo. Additionally, two sessions were specifically aimed at NMCA participants.Although initially intended to be a face-to-face event in London, the team rapidly adjusted to the emerging COVID-19 situation, identifying an online solution that facilitated and encouraged participant interaction. This meant that the events could still provide a platform for learning, discussion, and exchange of ideas that they have been able to in previous years, as well as providing opportunities to promote international collaboration in these topics. This special issue of the ISPRS International Archives of Photogrammetry, Remote Sensing and Spatial Information Sciences contains 23 papers selected by a double-blind peer review involving a minimum of two reviewers, presenting research on topics including visualisation, point cloud management, virtual reality, data interoperability, data quality, generating national 3D datasets, indoor 3D, urban planning/permits and underground data management.

THE EUROSDR GEOBIM PROJECT – DEVELOPING CASE STUDIES FOR THE USE OF GEOBIM IN PRACTICE

Abstract. 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.

THE CHANGING NATURE OF GEOSPATIAL DATA – CHALLENGES FOR A NATIONAL MAPPING AGENCY

Abstract. National Mapping and Cadastral Agencies have been creating geospatial products for customers for many decades and, in some cases, for over two centuries. During that time the nature of the products largely remained the same, consisting of cartographic representations of the world, usually generalized and projected in a two-dimensional form. Even when mapping agencies began to convert their mapping from paper to digital form, the products created were largely based on their paper map counterparts. In recent times, the general public has become far more aware of geospatial data due to global initiatives from Google, Bing, Apple, OpenStreetMap and others. While some users of geospatial data still require the same products as before, many other users need different kinds of geospatial data and products, ones which will provide new challenges to National Mapping and Cadastral Agencies. In this paper we discuss some of these new geospatial data users and illustrate some the challenges using an example from Ordnance Survey’s recent experience of a project in the connected autonomous vehicle domain.

EUROSDR GEOBIM PROJECT A STUDY IN EUROPE ON HOW TO USE THE POTENTIALS OF BIM AND GEO DATA IN PRACTICE

Abstract. In both the Geo and BIM domains, it is widely acknowledged that the integration of geo-data and BIM-data is beneficial and a crucial step in facing the multi-disciplinary challenges of our built environment. The result of this integration – broadly termed as GeoBIM – has a range of potential uses from district study to road safety. However, from the data perspective, this integration raises the question of how to integrate very detailed design and construction data from the BIM domain with contextual geospatial data (both 2D and 3D) that model a very diverse range of aspects of the wider built and natural environment.This paper reports work carried out during the second phase of the EuroSDR GeoBIM project, which sets out to understand the general status of GeoBIM across Europe with particular focus from a National Mapping and Cadastral Agency perspective. The first phase of the project reviewed the current status of GeoBIM in participating countries and identified the need for specific detailed use cases to overcome both the lack of awareness and the lack of understanding of the potential of GeoBIM. We present both an update on the current status of GeoBIM, and additional details of one of the selected use cases relating to planning/development permits. For the latter, we have been able to develop a detailed workflow highlighting specific data exchange points within the process to issue a development permit, allowing a more in-depth identification of both the roles and data needs at each stage.

Connecting users to trusted geospatial information for Europe

Abstract. In recent years, we have seen an explosion in location-based services. Whether it is maps, cadastral data or land registration, geospatial information is driving applications to realise social, economic and environmental benefits for us all. Yet in the age of ‘Big Data’ and the ‘Internet of Things’, how can we know which data sources are reliable and how easy is it to find accurate, high-quality and detailed information that we can trust? Knowing that reliable sources exist, and where to obtain them, is essential for governments and those making critical decisions that affect all our lives. As the official bodies responsible for national cadastre, land registration, geodetic surveying and mapping activities in Europe, European national mapping and cadastral agencies (NMCAs) fulfil an essential role providing definitive and detailed geospatial information. In an ever-changing world, NMCAs play an important and often critical role in helping to address the key global and regional issues that affect society, such as climate change, sustainable development, a digital economy, migration, security and health. With these challenges extending beyond national borders, society now expects a borderless digital economy and property market, as well as fully connected national databases for stronger cross-border emergency planning and environmental monitoring. As their membership association, EuroGeographics is committed to supporting European NMCAs as they improve access to their rich source of trusted, authoritative geospatial information. EuroGeographics is an independent international not-for-profit organisation representing Europe’s National Mapping, Cadastral and Land Registration Authorities. We believe in a society empowered by the use of trusted geospatial services from these official national sources. EuroGeographics strength lies in our extensive membership and we are proud to represent more than 60 organisations from 46 countries covering the whole of geographical Europe. We deliver benefits for each regardless of the geographical, technical, political, organisational, linguistic and business parameters in which they work. We support the public good by representing our members’ interests, maintaining networks that help our members improve their capabilities and role, and by facilitating access to and use of our members’ geospatial data and services. EuroGeographics’ has the strategic objective of facilitating access to our members’ authoritative data for international users of harmonised, pan-European, geospatial information and services. It coordinates the compilation and production of pan-European datasets, and has been active in exploring the development of online services. The Open European Location Services (Open ELS) project has developed services to demonstrate and test the level of interest in pan-European authoritative geospatial information. EuroGeographics has coordinated this two-year project which was co-financed by the European Union’s Connecting Europe Facility working with partners from member organisations in Finland, Germany, Great Britain, Norway, Poland, Spain, Sweden and The Netherlands. The Project has focused on facilitating access to, and encouraging the take up and use of this information, and is strongly user orientated with a programme of activities to support the digital economy. As well as test services, an Open ELS data policy has been developed which applies only to the geospatial pan-European data and services developed and maintained by EuroGeographics and its members through the Open ELS Project. The Policy was drafted using research which revealed the scope of open geospatial data from official national sources across Europe, and revealed the diversity of policy, business and legal approaches across Europe to what is ‘open’ data. Additional research, carried out by Deloitte and EuroGeographics, found that small and medium sized enterprises (SMEs) in Europe have a strong appetite for more cross-border authoritative data which could help them improve their product and service offerings, save money and become more competitive. The research highlighted four potential benefits from providing harmonised single access to pan-European geospatial information: The possibility to improve existing products and services offering; the possibility to develop new products and services; the reduced time and costs of dealing with different national mapping and cadastral agencies; and the reduced time and costs for acquiring and accessing data. Key findings from these research activities will be presented, along with an outline of the project, and what it has achieved.

INVESTIGATION INTO THE POTENTIAL OF SINGLE PHOTON AIRBORNE LASER SCANNING TECHNOLOGY

Abstract. Following several years of incremental technological developments in airborne laser scanning, the field is currently witnessing potentially revolutionary change through the introduction of new technologies, namely Single Photon (SP) and Geiger-Mode (GM) lidar. These new sensors potentially provide more efficient approaches to perform high-resolution 3D mapping, but seemingly to the detriment of accuracy and noise. Despite concerns, the technology is perceived to offer higher efficiency with respect to conventional airborne laser scanning and additional 3D mapping capability in terms of swath width, spatial resolution, acquisition time and density of range returns. These developments have led to some European National Mapping and Cadastral Agencies (NMCAs) to consider a potential change in their production pipelines, while some mapping companies are contemplating upgrading their existing airborne sensor systems. However, few open datasets and experiences are available to inform such decisions, and the community is keen to learn more about the technology and its deployment for 3D territorial mapping. These facts and considerations motivated EuroSDR Commission 1 to launch a new initiative in 2018 to better understand, explore and report to its NMCA membership the developments in SP and GM technologies. This paper describes the activities that have thus far been conducted as part of this EuroSDR initiative, comprising: a global on-line questionnaire into awareness of the technology; a preliminary investigation into a Leica SPL100 dataset of Easton, USA; and a community workshop at which a proposal to run an international benchmarking exercise was discussed.

Mapping Long-Term Dynamics of Population and Dwellings Based on a Multi-Temporal Analysis of Urban Morphologies

Information on the distribution and dynamics of dwellings and their inhabitants is essential to support decision-making in various fields such as energy provision, land use planning, risk assessment and disaster management. However, as various different of approaches to estimate the current distribution of population and dwellings exists, further evidence on past dynamics is needed for a better understanding of urban processes. This article therefore addresses the question of whether and how accurately historical distributions of dwellings and inhabitants can be reconstructed with commonly available geodata from national mapping and cadastral agencies. For this purpose, an approach for the automatic derivation of such information is presented. The data basis is constituted by a current digital landscape model and a 3D building model combined with historical land use information automatically extracted from historical topographic maps. For this purpose, methods of image processing, machine learning, change detection and dasymetric mapping are applied. The results for a study area in Germany show that it is possible to automatically derive decadal historical patterns of population and dwellings from 1950 to 2011 at the level of a 100 m grid with slight underestimations and acceptable standard deviations. By a differentiated analysis we were able to quantify the errors for different urban structure types.

APPROACHES TO DISTINGUISH ‘REAL’ CHANGES FROM ‘UNREAL’ CHANGES BASED ON MULTI-TEMPORAL 2D BUILDING FOOTPRINT DATA

Abstract. Building footprint data from National Mapping and Cadastral Agencies are available in Germany for 7 years as a uniform, nation-wide geospatial data set and are updated annually. These multi-temporal building data sets can form the basis for the application of change detection techniques to derive national figures on dynamics in the building stock. Since these building data sets have only been built up in recent years, it is necessary to distinguish real changes from false changes. This is done by applying vector geometry-based operations and statistical analyses, which are presented in this article. Furthermore, by the additional use of the raster dataset Copernicus – European Settlement Map (classified, resolution 2.5 m) it is approximately possible to estimate whether it is a correct change or not. The advantage of this approach is that large-scale comparable results can be derived simply and quickly based on uniform basic data.

USER REQUIREMENTS GATHERING FOR A NATIONAL 3D MAPPING PRODUCT IN THE UNITED KINGDOM

Abstract. One of the main barriers to the uptake of 3D GI is the lack of understanding of what the user requirements are. From the data acquisition and creation perspective – in particular, that of a National Mapping and Cadastral Agency who may need to prepare datasets with national coverage – this is an issue as each new 3D feature type and element within a feature added (such as doors, windows, chimneys, street lights) requires additional processing and cost to create. This paper reports the results of a user requirements gathering exercise for a national 3D mapping product in the United Kingdom. The study focuses on the user perception of ‘usefulness’ of different 3D geometry and semantic features. A web-based questionnaire with Likert-type items was selected as the primary data collection method and was conducted in May 2017. A total of 121 completed responses were from the UK. Descriptive analysis showed that ‘Air quality engineering’, ‘Infrastructure & transport’ and ‘Environmental services’ presented the most positive outlook on the usefulness of 3D. Correlation analysis showed that potential 3D product groups that could be formed in a multi-product approach. Cluster analysis showed that appetite for 3D information not only varies between sectors, but also within sectors between different practitioners. The results from exploratory factor analysis showed that users were more interested in additional information on non-building features rather than additional detail to building geometry. Further continued work is required to incorporate both non-GIS users and 3D users outside the GIS domain.

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

Abstract. 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.

USER REQUIREMENTS GATHERING FOR 3D GEOGRAPHIC INFORMATION IN THE UNITED KINGDOM

Abstract. Despite significant developments, 3D technologies are still not fully exploited in practice due to the lack of awareness as well as the lack of understanding of who the users of 3D will be and what the user requirements are. From a National Mapping & Cadastral Agency and data acquisition perspective, each new 3D feature type and element within a feature added (such as doors, windows, chimneys, street lights) requires additional processing and cost to create. There is therefore a need to understand the importance of different 3D features and components for different applications. This will allow the direction of capture effort towards items that will be relevant to a wide range of users, as well as to understand the current status of, and interest in, 3D at a national level. This paper reports the results of an initial requirements gathering exercise for 3D geographic information in the United Kingdom (UK). It describes a user-centred design approach where usability and user needs are given extensive attention at each stage of the design process. Web-based questionnaires and semi-structured face-to-face interviews were used as complementary data collection methods to understand the user needs. The results from this initial study showed that while some applications lead the field with a high adoption of 3D, others are laggards, predominantly from organisational inertia. While individuals may be positive about the use of 3D, many struggle to justify the value and business case for 3D GI. Further work is required to identify the specific geometric and semantic requirements for different applications and to repeat the study with a larger sample.