Building on the third dimension

Building on the third dimension

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As urbanisation prompts land administrators to look into the third dimension, an Australian university takes up a research project to incorporate 3D property information into land administration systems

Fig 1: 3D Land & property information management dimensions

More than half the world’s 7 billion people live in cities today. As urbanisation continues like never before, managing the growth of our existing cities and optimising the design of the future ones is critical for core city management applications such as urban planning, emergency response, asset management, navigation and intelligent transport systems.

Traditionally land and property information, which includes geometric, visual and legal data for each property unit, has been two-dimensional, based on 2D land parcels. However, over the past decade, urbanisation, high-rise apartments and the advent of complex building structures has prompted land administrators to incorporate the third dimension into the land development cycle, with the aim of enabling effective management and registration of 3D rights, restrictions and responsibilities.

To look into the challenges and the way forward towards a 3D land and property management system, the Centre for Spatial Data Infrastructures and Land Administration (CSDILA) of the Melbourne University has undertaken a research project, ‘Land and Property Information in 3D’. The research is supported by the Australian Research Council in close collaboration with government departments, surveying companies, architectural firms, body corporate and the Intergovernmental Committee on Surveying and Mapping (ICSM). The project also involves extensive international collaboration with a number of practitioners and researchers from countries around the world.

The core of this research lies in the culmination of the legal and physical components of our cities in a 3D environment (as illustrated in Figure 1) to enable a more complete and effective land and property information registration system, which will in turn help our governing bodies better manage our societies and future cities. Incorporating a 3D land and property information system becomes imperative since 2D survey plans are no longer able to represent the reality of inter-related titles and land uses with their complexities. Multiple page 2D plans cannot be easily understood or visualised outside the domain of the highly specialised professional surveyors. Additionally, 3D architectural drawings do not deliver legal authority in land and property registration. Modelling the 3D legal world and linking this to the physical world could facilitate a 3D land development process.

Objectives and methods

Specific objectives of the project are to deliver (a) an improved understanding of the problems and issues associated with incorporating 3D property information into land administration systems; (b) a specification of the technical, policy, legal and institutional aspects of a 3D property information and representation system; (c) a 3D data model and database management system; (d) a visualisation model for 3D information in land registration; and (e) a prototype 3D property information and building visualisation system.

Following an initial research scoping exercise, with a wide range of stakeholders and practitioners, the project has been classified into work packages.

Major developments & on-going research

The major outcomes from the first year of the project include the development of a 3D data model and visualisation prototype system which forms the first stage of a 3D land and property information platform.

3D data modelling

The project has extensively investigated data modelling for 3D land and property information and proposed a 3D cadastral data model (3DCDM) that provides a practical framework to model layered legal objects of survey plans and their physical counterparts using architectural and engineering plans. The data model is based on the requirements of 3D cadastre and provides a resilient starting point for developing a 3D cadastral database. The requirements of the 3D cadastre was gathered from the second International Workshop on 3D Cadastres, held in Delft, The Netherlands, and from a number of surveys conducted by the members of the ICSM as well as from discussions at a collaborative research workshop on ‘Land and Property Management in 3D’ held at the University of Melbourne, Australia. The 3DCDM consists of seven packages which collectively model both legal and physical entities of land and property information. As existing cadastral data models are defined purely as legal models, the 3DCSDM advances current systems by integrating the ‘real world’, or physical counterparts, inside the model. The inclusion of a representation of the actual construction of a building surpasses the representation of only the ownership boundaries by also including the physical information of a building which could greatly benefit applications such as real estate management.

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Further research is required to validate the model and examine approaches to implementation. Also, it is required to consider the role of building information modelling (BIM) and IFC in 3D cadastral data modelling. This would enable utilisation of the concept and terminologies of the existing related standards such as Land Administration Domain Model (LADM) to categorise the level of requirements (general and specific requirements).

 

3D data visualisation

Visualisations of current land and property information systems are generally paper based and in digital documents (PDF). Ownership boundaries are commonly drawn on floor plans with cross-sections or isometric diagrams used to represent the 3D property rights. This project proposes a set of requirements for interactive 3D cadastral visualisation systems. Similar to the data model, the visualisation system represents not only the physical objects, but also their legal counterparts. The results of the research form a prototype Web-based 3D visualisation system developed using WebGL. The prototype consists of an integration of different layers which enables different semantically rich visualisations based on the application requirements. There are options for 2D paper plans as well as fully interactive 3D virtual environments. Based on client-server architecture, the system uses PostgreSQL which is an open-source database to store 3D models in an XML based format. Using the Google Earth API, the platform provides a ‘city view’ with georeferencing functionality. A ‘building view’ enables detailed visualisation of individual buildings.

3D data sourcing

Over the past decade, significant developments in 3D data acquisition techniques, visualisation, image processing algorithms and computer power, as well as trends such as volunteered geographic information (VGI) and BIM have facilitated the creation of 3D models of buildings and cities around the world. The application of these models for 3D land and property registration gives rise to unique opportunities and novel research challenges. The aim of this part of the research is to assess the advancements in data sourcing by examining 3D acquisition methods, visualisation platforms, image processing algorithms and future trends with a focus on improving current practice in land and property information registration.

An integral part is to investigate the integration of 3D data from a number of sources, including close-range photogrammetry, aerial imagery, mobile mapping and UAVs together with architectural and survey plans. The results aim for a complete and detailed interactive model of buildings that integrates both indoor mapping with photorealistic, accurate building reconstructions.

Institutional challenges

The implementation and transition to a 3D land and property information system is not simply a technical challenge. A crucial aspect is to examine the institutional structures around the current land development process to determine how, and where, 3D systems could be most critically adopted. An empirical understanding of the institutional influences and their mechanisms is likely to lead to the use of 3D digital building information technologies, ultimately facilitating productivity of the land development process for urban landscapes and complex building structures.

Future direction

The completion of the first year of research has seen a number of notable achievements, including the development of a 3D cadastral data model and 3D visualisation prototype system, which form the foundation of the project. Over the next few months, the research team will investigate 3D data sourcing methods with a particular focus on UAVs. The research team will also conduct a widespread survey to clearly define requirements for 3D visualisation gathering data from key players in the land development lifecycle, including surveyors, land developers, architects, government and the private sector. Integration with BIM is also integral to this project.

The authors would like to acknowledge and thank the Australian Research Council Linkage Program, project partner organisations and members of the 3D research team at the Centre for Spatial Data Infrastructures and Land Administration, the University of Melbourne.)