Patent ID: 6029173
Filing Date: 2000-02-22
Classification: G01C,Y10S

Abstract:
A method of displaying physical geographic features on a computer output device using a geographic database stored on a computer readable medium for use in a computer based navigation system wherein said geographic database comprises:an indexed normalized shape array, said indexed normalized shape array comprising a plurality of entries, each of said plurality of entries comprising one or more polynomial equation coefficients and an index reference value;a plurality of road segment data entities, each of said plurality of road segment data entities comprised of shape data attributes and node data attributes wherein said shape data attributes contain a representation of a physical geographic feature in the form of an index reference value corresponding to an entry in said indexed normalized shape array and further wherein said node data attributes represent geographic location points;the method comprising the steps of:determining the selected geographic feature to display on said computer output device;locating the corresponding road segment data entity and the associated shape data and node data attributes to said selected geographic feature;reading the index reference value stored in said shape data attributes of said road segment data entity;indexing into said normalized shape array using said index reference value and reading the polynomial equation coefficients from the corresponding entry;calculating a polynomial curve based on geographic location information contained in said node data attributes and said polynomial equation coefficients; anddisplaying said polynomial curve on said computer output device.