Componentized Junction Models

Abstract

A plurality of road junction configurations are defined with a different set of road segment models corresponding to each of the plurality of road junction configurations. One of the plurality of road junction configurations are selected for a route through a physical road junction. A model of the physical road junction is generated by assembling the set of road segment models corresponding to the selected road junction configuration. The three-dimensional model of the physical road junction is rendered.

We claim: 
     
         1 . A method for constructing a componentized junction model using a lookup table, the method comprising:
 calculating, from map data, a route through a physical road junction;   selecting, from a lookup table, one of a plurality of road junction templates for the route through the physical road junction, each road junction template specifying a different set of short road segment components, wherein the selected road junction template is a closest fitting road junction configuration to the physical road junction;   generating a model of the physical road junction by assembling the set of short road segment components specified for the selected road junction template in the lookup table; and   rendering the model of the physical road junction for display to a user.   
     
     
         2 . The method of  claim 1 , wherein the lookup table is associated with the map data and identifies each of the plurality of road junction templates for modeling physical road junctions stored in the map data. 
     
     
         3 . The method of  claim 1 , wherein a fidelity of the generated model of the physical road junction is increased or decreased by varying the number and type of road segment components specified in the plurality of road junction templates. 
     
     
         4 . The method of  claim 1 , wherein generating the model comprises:
 assembling the set of short road segment components in a specific order stored in the lookup table.   
     
     
         5 . The method of  claim 4 , wherein the specific order is stored in a syntax for the plurality of road junction templates. 
     
     
         6 . The method of  claim 1 , wherein the selected one of the plurality of road junction templates is a single decision point comprising an originating link component, a decision point component, and at least one destination link component. 
     
     
         7 . The method of  claim 1 , wherein the selected one of the plurality of road junction templates is a multiple decision point comprising an originating link component, decision point components, an intermediate link component, and at least one destination link component. 
     
     
         8 . The method of  claim 1 , wherein the generated model of the road junction is a three-dimensional model. 
     
     
         9 . The method of  claim 1 , further comprising:
 displaying the rendered model of the road junction.   
     
     
         10 . The method of  claim 1 , wherein the rendered model of the road junction is a static two-dimensional rendering or an animated three-dimensional rendering. 
     
     
         11 . A method for constructing a componentized junction model, the method comprising:
 calculating, by a navigation system, a route through a physical road junction;   selecting, by the navigation system, one of a plurality of road junction templates for the route through the physical road junction, each of the plurality of road junction templates comprising a predefined syntax identifying a different set of predefined road segment components, each predefined road segment component representing a short road segment interconnectable with at least one other road segment component;   modeling, by the navigation system, the physical road junction based on the predefined syntax of the selected one of the plurality of road junction templates;   rendering, by the navigation system, the three-dimensional model of the physical road junction, and   providing, by the navigation system, navigation instructions through the physical road junction with the rendered three-dimensional model of the physical road junction.   
     
     
         12 . The method of  claim 11 , wherein calculating the route comprises:
 applying junction inclusion rules to identify the physical road junction to be associated with the one of the plurality of road junction templates.   
     
     
         13 . The method of  claim 11 , wherein the predefined syntax identifies the selected template as a single decision point junction. 
     
     
         14 . The method of  claim 13 , wherein the predefined syntax comprises lane count and lane connectivity for an originating link component, a decision point component and at least one destination link component of the single decision point junction. 
     
     
         15 . The method of  claim 11 , wherein the predefined syntax identifies the selected template as a multiple decision point junction. 
     
     
         16 . The method of  claim 15 , wherein the predefined syntax comprises lane count and lane connectivity for originating link component, decision point components, an intermediate link component, and destination link components of the multiple decision point junction. 
     
     
         17 . The method of  claim 11 , wherein the predefined road segment components comprise an overpass road segment component or an underpass road segment component. 
     
     
         18 . A navigation system for constructing a componentized junction model:
 a memory configured to store map data and a plurality of road junction templates in a lookup table;   a processor configured to:
 calculate, from the map data, a route through a physical road junction; 
 select, from the lookup table, the closest fitting one of the plurality of road junction templates for the route through the physical road junction; 
 model of the physical road junction by assembling a set of road segment components specified by the lookup table for the selected road junction template; and 
 render the model of the physical road junction; and 
   a display configured to display navigation instructions through the physical road junction with the rendered three-dimensional model of the physical road junction.   
     
     
         19 . The navigation system of  claim 18 , wherein the plurality of road junction templates are coded in the lookup table with a syntax identifying the type of road junction. 
     
     
         20 . The navigation system of  claim 19 , wherein the syntax identifies a specific order of road segment components for modeling the physical road junction.