1. A system for providing three-dimension visual navigation for a mobile unit: a location calculation unit for calculating an instantaneous position of the mobile unit; a viewpoint control unit for determining a viewing frustum based on the position of the mobile unit; a scenegraph manager in communication with at least one geo-database, the scenegraph manager obtaining geographic object data associated with the viewing frustum from the at least one geo-database and generating a scenegraph that organizes the obtained geographic object data; and a scenegraph renderer for graphically rendering the scenegraph as a three-dimensional depiction in real time.