Visual conflicts - Challenges in combining rich volumetric 3D-data in a realistic VR city model

This paper presents a work in progress on how to visualize the impact of vegetation on urban air quality in a virtual city model, explorable using virtual reality (VR). The transdisciplinary project CityAirSim - Visualizing and modelling urban air quality - influence of vegetation, building morphology and traffic emissions develops a modelling framework to simulate the effects of vegetation, buildings and traffic strategies on air pollution, in order to understand the synergies and conflicts between these factors. The resulting data will be visualized in a VR-application allowing interactive exploration. Two primary target groups for the VR-application are high school students and urban planners. We aim for the tool to be used in teaching, e.g., in environmental science, as well as in communication with the public in exhibition environments, such as science centers. This paper focuses on how we should visualize invisible air pollution in an otherwise realistic urban setting to facilitate understanding. One important aspect to consider is to create a visual balance between data visualization and the visualization of the built environment in the model. Another aspect is to define the appropriate levels of data visualization and abstraction of representation to use, without losing richness of information.