Method and system for representing pedestrian crosswalks in a geographic database used by a navigation system

1. A geographic database that represents a road network in a geographic area, comprising:

data entities that represent road segments;

data entities that represent nodes located at both endpoints of the road segments, wherein a location of an intersection of at least two roads represented by the road segments is represented by a single node;

data representing corners located at the intersection;

data identifying whether a crosswalk connects two of the corners located at the intersection; and

data identifying a code representing an appearance type of the crosswalk connecting two corners of the intersection, wherein a processor of a navigation system is configured to provide crosswalk type information according to the code representing the appearance type of the crosswalk connecting two corners of the intersection,

wherein the code representing the appearance type of crosswalk is based on crosswalk markings located on a road.

2. The geographic database of claim 1 , wherein the crosswalk markings are selected from the group consisting of solid, standard, continental, dashed, zebra, and ladder.

3. The geographic database of claim 1 , wherein the appearance type of crosswalk is based on presence of at least one of a pedestrian tunnel, a pedestrian bridge, a crossing light, and a crossing signal.

4. The geographic database of claim 1 , wherein the data representing the corners located at the intersection is associated with the data entities that represent the road segments.

5. The geographic database of claim 1 , wherein the data representing the corners located at the intersection includes a reference to an identifier of a road segment located closest to the corner in a circular manner.

6. The geographic database of claim 1 , wherein the data identifying whether a crosswalk connects two corners located at the intersection includes a pair of corner labels associated with the two corners connected by the crosswalk.

7. The geographic database of claim 6 , wherein the pair of corner labels includes data associated with the road segments that form the intersection.

8. A navigation system comprising:

a geographic database that represents a road network in a geographic area, the geographic database comprising:

data entities that represent road segments;

data entities that represent nodes located at both endpoints of the road segments, wherein a location of an intersection of at least two roads represented by the road segments is represented by a single node;

data representing corners located at the intersection that includes a corner label identifying a road segment located closest to the corner in a circular manner;

when a crosswalk is located at the intersection, data representing a pair of corner labels that identifies the two corners connected by the crosswalk;

data identifying an appearance type of the crosswalk; and

a processor configured to provide a crosswalk type code to the navigation system according to the appearance type of the crosswalk based on crosswalk markings located on a road.

9. The geographic database of claim 8 , wherein the crosswalk markings are selected from the group consisting of solid, standard, continental, dashed, zebra, and ladder.

10. The geographic database of claim 8 , wherein the appearance type of crosswalk is based on presence of at least one of a pedestrian tunnel, a pedestrian bridge, a crossing light, and a crossing signal.

11. A navigation system, comprising:

a geographical database including:

an identifier for road segments associated with an intersection;

a label for each corner of the intersection, wherein the label is based on the road segment identifier associated with the road segment located closest to the corner in a circular manner;

a pair of corner labels that identify corners connected by the crosswalk; and

a code representing an appearance type of the crosswalk based on crosswalk markings located on a road; and

a processor configured to provide crosswalk type information to the navigation system according the code representing the appearance type of the crosswalk.

12. The geographic database of claim 11 , wherein the crosswalk markings are selected from the group consisting of solid, standard, continental, dashed, zebra, and ladder.

13. The geographic database of claim 11 , wherein the appearance type of crosswalk is based on presence of at least one of a pedestrian tunnel, a pedestrian bridge, a crossing sight, and a crossing signal.

14. The geographic database of claim 11 , further comprising an identifier for a node that represents the intersection, wherein the label is further based on the node identifier associated with the intersection.

15. A method for providing crosswalk guidance to an end-user of a navigation system, comprising:

as the end-user approaches an intersection, a navigation system determining whether a crosswalk is located between two corners of the intersection;

the navigation system identifying a crosswalk is located between two corners of the intersection;

the navigation system retrieving geographic data from a geographic database representing the two corners and a code for an appearance type of pedestrian crosswalk based on roadway crosswalk markings; and

the navigation system providing the end-user information regarding the crosswalk based on the retrieved geographic data representing the two corners and the appearance type of the pedestrian crosswalk.

16. The method of claim 15 , wherein the geographic data representing the two corners includes data associated with road segments that form the intersection.

17. The method of claim 15 , wherein the geographic data representing the two corners includes a pair of corner labels.

18. The method of claim 17 , wherein each of the corner labels includes a reference to an identifier of a road segment located closest to the respective corner in a circular manner.