Representations built from a true geographic database

The development of a system for geovisualisation under the Centre for 3D GeoInformation at Aalborg University, Denmark, has exposed the need for a rethinking of the representation of virtual environments. Now that almost everything is possible (due to technological advances in computer graphics) within the creation of Virtual Environments, what will be the next challenge within Urban simulation and modelling to overcome? It will certainly not be to create the models as real as possible or refine details in the texturing. The challenge will be to do a proper object-orientation and thereby secure a representation based on geographic and geospatial principles. The system GRIFINOR, developed at 3DGI, Aalborg University, DK, is capable of creating this object-orientation and furthermore does this on top of a true Geographic database. A true Geographic database can be characterized as a database that can cover the whole world in 3d and with a spatial reference given by geographic coordinates. Built on top of this is a customised viewer, based on the Xith(Java) scenegraph. The viewer reads the objects directly from the database and solves the question about Level-Of-Detail on buildings, orientation in relation to terrain and rendering of the model. All this is done in something very close to real-time. GRIFINOR is at the moment working within a limited edition of the world. Only a few classes have been selected for representation in GRIFINOR. These are buildings, cadastre, trees, grass, roads. This paper will discuss different possibilities for representation of the objects from a geovizualisation aspect