3D vectorization and rasterization of CityGML standard in wind simulation

Abstract

Wind flow is one of the elements that influence the dispersion of pollutants in air pollution events. The wind flow can be observed using the Computational Fluid Dynamics (CFD) technique. Attachment of the building model is required to monitor the wind flow of the urban area as the building's existence manipulates the movement of the wind throughout the urban area. In the meantime, prior research used building models with no specific modelling standard incorporated into the simulation environment. However, this research employs the building standard of City Geographic Markup Language (CityGML) to model the building involved. As referred to in the earlier research, the present level of detail 3.1 (LoD3.1) model is the least detail LoD suitable to visualize the wind simulation, this model is used as the original model to be compared with the newly generated model in 3D raster type. The vector data type is the model in the specified LoD of the CityGML standard. This study investigates the amalgamation of the raster model in the simulation environment by comparing the edge length, the simulation result, and the computational time of the rasterized model with the vectorized model. A slight edge length difference of approximately 14.5 cm is shown by the raster model. However, its simulation environment yields acceptable error values for wind velocity and pressure difference of 0.089 and 0.096, respectively, and outperforms the vector environment with a 50.4% shorter computational time. The investigation concludes that the 3D rasterized model is compatible with the wind simulation environment.