Method and apparatus for generation of real-time graphical descriptions in navigational systems

Abstract

A method and apparatus for generating real-time, symbolic descriptions for a navigational system is provided. The method may be employed within a variety of devices, including in-vehicle navigation systems, cellular telephones and PDAs. The method takes geographical coordinates corresponding to an oncoming maneuver, like a right-hand turn at a four-way intersection for example, and transforms them into a set of two-dimensional, planar coordinates. The method then maps these planar coordinates atop a pie-shaped, radial grid, and allocates points to subdivisions of the grid by counting the number of points that fall within the grid. The method then generates a symbolic description of the maneuver to be performed by drawing an arrow running from the beginning of the maneuver to the end of the maneuver atop a predetermined, generic description of the intersection. This real-time, graphical maneuver description is then displayed on a screen to a user. The use of the radial grid eliminates the need of performing complex, angular calculations with a local processor, and further eliminates the need of storing large image files in local memory.