  3D city models - which represent in 3 dimensions the geometric elements of a
city - are increasingly used for an intended wide range of applications. Such
uses are made possible by using semantically enriched 3D city models and by
presenting such enriched 3D city models in a way that allows decision-making
processes to be carried out from the best choices among sets of objectives, and
across issues and scales. In order to help in such a decision-making process we
have defined a framework to find the best visualization technique(s) for a set
of potentially heterogeneous data that have to be visualized within the same 3D
city model, in order to perform a given task in a specific context. We have
chosen an ontology-based approach. This approach and the specification and use
of the resulting ontology of 3D visualization techniques are described in this
paper.
