Cartographie d’aujourd’hui et de demain : rappels et perspectives

We start from the fact that each spatial object i is characterized by three coordinates: x (latitude), y (longitude) and z (by tradition elevation). The discussion proposed here turns around three axes: first, we remind some of the main problems when representing a volume (ellipsoid) on a plane (map). Second, we discuss some elementary principles of cartography in order to show the importance of the nature of z in thematic mapping. Third and last, we show how far the realistic representation of the third dimension can be improved by visualization techniques, a modern discipline close but different from cartography.