KEY WORDS: 3D visualization, information visualization, 3D city model, 3D virtual environment, 3D GIS, knowledge base ABSTRACT:Virtual 3D city models are used for different applications such as urban planning, navigation, pedestrian behaviour, historical information, and disaster management. These applications require rich information models that associate urban objects not only with their geometric properties but also with other types of information. When designing such models the choice of visualization techniques is far from trivial because the city objects must be displayed together with additional information, such as historical facts, planning projects, pollutant concentration, noise level, etc. Finding relevant techniques depends on a set of criteria such as the type of information, but also on the tasks that will be performed and the associated context. Furthermore, a technique that is relevant when used in isolation may generate visual incompatibilities when used in conjunction with another one. We have defined a model for the representation of information visualization techniques in 3D city models. We have implemented this model in the form of an ontology and a knowledge base of techniques currently used in 3D city models or 3D GIS. The goal of such an approach is to provide a knowledge repository to support the design of 3D virtual city models in which non-geometric information must be presented. In this paper we describe the model and the ontology of information visualization techniques that we designed. We also show how the associated knowledge base can be used for the selection of visualization techniques depending on different criteria including task and context, and for the detection of visual incompatibilities between techniques when used in the same scene.

Abstract. Models, which represent in 3 dimensions the geometric elements of a city, are called 3D city models. Those models are used for an intended wide range of applications beyond mere visualization. Such uses are made possible by enriching the geometrical aspects with urban or environmental data that cannot be perceptible to a user without a visual abstraction. Using such models implies interacting with them in order to perform specific tasks related to the visualized data. Those data are potentially heterogeneous in terms of types, scales, issues, etc. When creating an enriched 3D city model, the designer faces the problem of choosing the most relevant visualization techniques for those heterogeneous data that have to be displayed within the same scene. In this paper we address the problem related to the visualization of enriched 3D city models by proposing a formal representation of existing visualization techniques in the form of an ontology of 3D visualization techniques. We also show how this ontology can be used for computational reasoning and help for the selection of visualization techniques by checking if a technique is compatible with a dataset to display or to a technique already selected and used in the same scene.

No abstract

KEY WORDS: 3D visualization, information visualization, 3D city model, 3D virtual environment, 3D GIS, knowledge base ABSTRACT:Virtual 3D city models are used for different applications such as urban planning, navigation, pedestrian behaviour, historical information, and disaster management. These applications require rich information models that associate urban objects not only with their geometric properties but also with other types of information. When designing such models the choice of visualization techniques is far from trivial because the city objects must be displayed together with additional information, such as historical facts, planning projects, pollutant concentration, noise level, etc. Finding relevant techniques depends on a set of criteria such as the type of information, but also on the tasks that will be performed and the associated context. Furthermore, a technique that is relevant when used in isolation may generate visual incompatibilities when used in conjunction with another one. We have defined a model for the representation of information visualization techniques in 3D city models. We have implemented this model in the form of an ontology and a knowledge base of techniques currently used in 3D city models or 3D GIS. The goal of such an approach is to provide a knowledge repository to support the design of 3D virtual city models in which non-geometric information must be presented. In this paper we describe the model and the ontology of information visualization techniques that we designed. We also show how the associated knowledge base can be used for the selection of visualization techniques depending on different criteria including task and context, and for the detection of visual incompatibilities between techniques when used in the same scene.