Modelling Oceanographic Data with the Three-dimensional Voronoi Diagram

Managing oceanographic data with traditional geographical information systems (GIS) is a difficult task because these systems have been primarily designed for land-based applications. The main problem is that the nature of objects at sea is completely different from the nature of objects found on the land: at sea most objects are represented by unconnected points that can have threedimensional coordinates, the datasets have 'abnormal' distribution and the objects tend to change position over time. We propose in this paper using a spatial model based on the three-dimensional Voronoi diagram (VD) to handle topological relationships between objects. We present the main properties of the 3D VD, algorithms to construct and modify it, and show how some 3D GIS operations are greatly simplified when a spatial model is built upon it