Methods for storing simulation output in semantic 3D city models

English. Currently, there is no direct support for storing simulation output within semantic 3D city models (CityGML). This master thesis explores a potential methodology for this purpose, with a focus on using appearances of 3D geometries instead of creating generic city objects and attributes or adding an Application Domain Extension (ADE). The caveat with the last two methods is that they require additional changes or extensions to the CityGML schema and introduce interoperability issues. It means that 3D models and simulation output cannot be processed and/or visualized in one software simultaneously, instead this has to be done utilizing different software. This workaround increases the processing time of the simulation output. To address these challenges, this thesis proposes a third option: utilizing the 3DCityDB appearance module, which can store surface-related visualization, including non-visible specifications like daylight and sunlight simulation outputs. This method leverages existing CityGML and 3DCityDB structures to integrate simulation outputs without extending the schema, thereby simplifying the process for urban planners or other decision makers while maintaining model efficiency. The thesis aims to bridge the gap between utilizing extensive simulation data—specifically sunlight and daylight simulation outputs—and the capacity of 3D city models to effectively incorporate this information. By implementing and testing the use of the appearance module, the proposed methodology demonstrates its feasibility for storing, querying (SQL), and visualizing simulation outputs. The thesis work concludes that the appearance module of CityGML can be used to store sunlight and daylight simulation data in 3DCityDB successfully. The integration process has been validated, ensuring accurate implementation within the CityGML schema. Additionally, the thesis work confirms that querying and retrieving appearance data may simplify established work practices related to the urban planning process, further promoting the utilization of CityGML models in this branch. This advancement provides a valuable tool for decision-makers, particularly in assessing compliance to daylight regulations at different stages of the urban planning process.

English. 3D city models are powerful tools used for urban planning and analysis, but they currently lack direct support for storing detailed simulation data, like sunlight and daylight simulations. This master thesis explores a new method for incorporating such simulation data into 3D city models, specifically focusing on CityGML, a common standard for 3D city models. Problem Traditionally, storing simulation output within CityGML requires modifying the standard structure, which creates issues. First, modifying CityGML to include simulation data requires extra extensions, making the process more complex. Second, different software is needed to process and visualize these modified models, which slows down the workflow. Proposed Solution The thesis proposes using the existing 3DCityDB appearance module to store simulation data. This module is typically used for visual details on 3D models, but it can also handle data like sunlight and daylight simulations without changing the CityGML structure. Method Instead of adding new objects or attributes to CityGML, the thesis uses the appearance module to include simulation data. The appearance module can store surface-related data and allows querying and visualizing this data within the same software, making the process more efficient. Results The research demonstrates that the appearance module can store and manage modified simulation data. This method allows querying and visualizing simulation outputs, making it easier for urban planners to use this data. Furthermore, it supports compliance checks for daylight regulations in urban planning. Conclusion Using the 3DCityDB appearance module to store simulation data in CityGML is a practical and efficient solution. It helps urban planners and decision-makers better integrate and utilize simulation outputs in their 3D city models.