All 10 million buildings in the Netherlands available as 3D models
Wind turbulence in an office district, noise nuisance from an industrial park, horizon-polluting windmills near a residential area, blinding light in classrooms. Often unexpected, such things can range from being a nuisance to highly annoying after a construction has been completed. We can now more easily simulate these effects on the living environment before construction, as detailed 3D data is now available for all 10 million buildings in the Netherlands.
The planning and development of urban areas requires careful weighing of the pros and cons of many aspects like noise, wind, light ingress, and sustainability, to mention just a few. The 3D building models, also called urban digital twin, can be used to simulate what-if scenarios. Simulations enable us to determine the impact of different design options on the living environment during the design phase. The design can be adapted in accordance to the outcome, and thus better-informed and evidence-based decisions can be made that lead to the optimal design.
Virtual 3D models have been used for some time within such domains as solar energy, wind and ventilation, noise and air quality, but until recently it took a lot of effort to generate suitable 3D building models for a specific application. This virtual model of our environment means a 3D dataset is available that all domains can use directly and freely.
The data and underlying technology have been made available as open data and open source software to stimulate the numerous potential innovations as much as possible.
Point clouds and laser beams
Using a new reconstruction method for buildings, the 3D models of all 10 million buildings in the Netherlands have been generated fully automatically. Until recently, this required semi-automated processing which made it difficult to reconstruct large areas. The method uses 2D building footprints from the National Key Register of Addresses and Buildings (BAG) as input and the developed service is therefore called 3D BAG. A point cloud (Actueel Hoogtemodel Nederland) is used to derive the height information. This point cloud data is collected using laser altimetry: a laser beam is sent from an airplane or helicopter to the earth and the response time used to determine the height at that location. The AHN has a point density of approximately 10 points per square meter and is available as open data for the whole of the Netherlands.
The main challenge was to develop algorithms that are flexible enough to automatically generate a simple and accurate 3D model for any kind of building, regardless of the roof shape. In addition, the algorithms must be able to robustly process all kinds of source data with varying qualities. This requires algorithms that can take the technical limitations into account, such as height data with varying quality obtained from an airplane or helicopter via laser scanning. For example, heights of buildings in dense urban areas cannot always be detected due to occlusion by other buildings and therefore height points are sometimes missing in the input point cloud data. For such cases, the algorithm cannot always reconstruct a correct 3D model. In future research we will further address these kinds of technical limitations, for example by using artificial intelligence to fill the gaps in the point cloud.
The stable version of these 3D BAG developments at TU Delft is forwarded to the 3D base-data facility of the Netherlands’ Cadastre, Land Registry and Mapping Agency (Kadaster, www.pdok.nl/3d-basisvoorziening). The models can be used as 3D-basis in the digital information infrastructure of the new Environment and Planning Act.
We are studying in projects with various partners how to optimally connect the 3D data to urban applications in practice. An important application is noise simulation. For this domain, a national dataset was recently generated in collaboration with the Kadaster and RIVM.
Maintaining our own version of the 3D BAG service in Delft allows us to continuously improve and extend every part of the workflow: from input data preprocessing to reconstruction, 3D visualisation and use in urban applications.
The technology behind the 3D BAG service was developed by the 3D Geoinformation research group, Department of Urbanism, in various research projects, with funding from the European Commission (ERC), the Netherlands Organization for Scientific Research (NWO), and the Amsterdam Institute of Advanced Metropolitan Solutions (AMS). We improved the algorithms further in collaboration with partners such as RIVM, Rijkswaterstaat and the Kadaster.
More information about the applications and possibilities of 3D Geoinformation can be found here.
Contact: Jantien Stoter