Text: Cornelia Freund
The work of geoinformaticians serves science, business and administration as a basis for sustainable, innovative urban planning. Analyzing life cycles of buildings, deriving key figures - the digital model or a digital drill cloned from it makes it possible to represent these what-if scenarios. "Standardizations that make scientific results transferable to other cities are important," says Kolbe, explaining his approach: "After all, we don't conduct research as an end in itself, but rather support stakeholders from companies, urban development and civil society with our fund of methods and tools."
In 2003, he initiated the CityGML standard and set standards in the international environment. Many megacities such as Tokyo, Singapore, or New York and metropolises such as Helsinki, Rotterdam, Vienna, Hamburg, or Munich now use the format. But also national geodata on the total inventory of all buildings in Germany or the Netherlands are recorded and structured according to the CityGML standard. The standard allows to model urban objects with their 3D geometry and topology, semantics and appearance in different versions and details. In the most recently released version 3.0, highly dynamic information, such as solar radiation during the course of the day, water levels of floods, traffic densities in individual streets can also be represented and any sensors can be linked to 3D models.
In the Engine Room of 3D City Model Development
Within the TUM School of Engineering and Design, there is a lively exchange between researchers. "We are the engine room for colleagues who use semantic 3D city models for their respective specialist topics," emphasizes Kolbe. Digital models are already in use in various use cases and across research disciplines.
"A team at the Chair of Traffic Engineering is simulating traffic in the Bavarian metropolis in the "Digital Twin Munich" project and converting mobility scenarios into 3D visualizations using game engines," recounts project manager Dr. Andreas Donaubauer. Simulators and virtual reality glasses make it possible to experience what it feels like to ride a cargo bike or a wheelchair on Munich's streets. The aim is to identify and prevent potentially dangerous situations at an early stage in traffic planning.
Munich citizens have already been able to experience the vivid digital 3D city model, for instance, in a public discussion on bike paths on the Boschetsrieder Street. Here, the mobility department of the Bavarian state capital used virtual reality to illustrate developments and enable citizen participation.
Chair member Christof Beil developed a playful approach to a digital participation process by calculating a Minecraft model of the Olympic Stadium. The model, with its computer game look, is intended to encourage younger citizens to engage creatively with the development of their living space and to create spaces for innovation.
How interdisciplinary science uses city models from Kolbe's team is also shown by the example of Dr.-Ing. Hannes Michael Harter, who examined the life cycles of large residential buildings on the basis of semantic 3D city models in his dissertation at the Chair for Energy Efficient and Sustainable Planning and Building, calculating the cities of Munich and New York City. The results of his work show that despite ambitious development scenarios for large building stocks, considerable energy requirements and resulting high CO2 emissions and costs are incurred.
The cataloging of the City
Whether it's energy, noise or particulate matter: To ensure that life in metropolitan areas remains livable, municipalities must plan reliably. The "Smart District Data Infrastructure" (SDDI) concept provides planners with the necessary, flexible tool. Developed at the Chair of Geoinformatics at TUM, the catalog can be used to map cities or individual districts as virtual 3D city models and link them to dynamic data - city climate measuring points, weather radar, consumption meters/smart meters and video cameras. In this way, future developments can be vividly simulated and approaches to solutions can be developed at an early stage across disciplines. What makes the SDDI framework unique is that the semantic 3D city model is the hub for all data, on the basis of which information systems are intelligently networked.
Citizens, the city administration, utilities, transportation companies and the real estate industry can use it to calculate energy requirements or the solar energy potential for buildings, for instance, or to simulate traffic density and pedestrian flows, noise propagation or flooding. The SDDI, which is based on open standards, considers the effects of planned construction projects on the environment, mobility, energy and social issues simultaneously.
Continuing Education Program for interdisciplinary Solutions
The TUM Institute for Life Long Learning offers a certificate course "Digital Twins for Cities". The part-time continuing education program was designed at TUM's Leonhard-Obermeyer-Center, with Thomas H. Kolbe (Chair of Geoinformatics), Prof. André Borrmann (Chair of Computational Modeling and Simulation), and Prof. Frank Petzold (Chair of Architectural Informatics) responsible for the scientific design. In its cross-thematic approach, the program combines the fields of digital building (BIM) and digital urban modeling (CityGML) with innovative analysis and simulation methods for the design of smart urban spaces.
Further Information and Links
Monitoring of the Digital Twin Munich project by the Chair of Geoinformatics:
https://www.asg.ed.tum.de/en/gis/news/article/scientific-support-of-the-city-of-munich-in-the-creation-of-the-citys-digital-twin/
Geobased Digital Twin Bavaria and SDDI
https://wiki.tum.de/display/dzb/Geobasierter+Digitaler+Zwilling
Interactive 3D city models online demos: https://wiki.tum.de/display/gisproject/Online+Demo+Collection
Open source geodatabase system for the management of 3D city models (developed under the leadership of the Chair of Geoinformatics; in professional use worldwide):
https://www.3dcitydb.org/
International CityGML standard:
https://www.ogc.org/standards/citygml