3D City Model Visualization with Cartography-Oriented Design

This paper investigates and discusses concepts and techniques to enhance spatial knowledge transmission of 3D city model representations based on cartography-oriented design. 3D city models have evolved to important tools for urban decision processes and information systems, especially in planning, simulation, networks, and navigation. For example, planning tools analyze visibility characteristics of inner urban areas and allow planers to estimate whether a minimum amount of light is needed in intensely covered areas to avoid “Gotham city effect“, i.e., when these areas become too dark due to shadowing. For radio network planning, 3D city models are required to configure wireless network services, i.e., to calculate and analyze network coverage and connectivity features. 3D city model visualization often lacks effectiveness and expressiveness. For example, if we analyze common 3D views, large areas of the graphical presentations contain useless or even “misused” pixels with respect to information content and transfer (e.g., pixels that represent several hundreds of buildings at once or pixels that show sky). Typical avatar perspectives frequently show too many details at once and do not distinguish between areas in focus and surrounding areas. In this case the perceptual and cognitive quality of visualized virtual 3D city model could be enhanced by cartographic models and semiotic adaptations. For example, we can integrate strongly perceivable landmarks as referencing marks to the real world, which establish more effective presentations and improve efficient interaction. The referencing aspect in depictions of 3D city models is essential: Only correctly perceived elements can fulfill referencing tasks. With misleading perception, the same elements may cause false understanding. This circumstance leads to media-dependent semiotic models that aim at supporting effective transmission of spatial contents. This contribution compares different dynamic 3D visualization approaches for virtual 3D city models and demonstrates applied cartographic techniques to enhance information transfer. The underlying concept is based on a model for 3D semiotics, includes a number of pragmatic components, and presents examples of visualizations of adapted 3D city model visualizations.