Navigation system

Abstract

When a display area for map information is reduced to a specified scale for a wide area display, items of congestion information are extracted which have a congestion level of “congested or busy”, and an overlap determination area is created for a congestion link of each item of the extracted congestion information. The overlap determination area extends both transversely and longitudinally for a specified distance from the congestion link. Also, for each group of congestion information items having overlapping determination areas, an equal congestion level area is created by connecting the overlap determination areas. The equal congestion level area is displayed on a liquid crystal display in a color that corresponds to the congestion level of the equal congestion level area. The equal congestion level areas are also created in the same manner for the congestion information items with congestion levels of “congested” and “not congested”, and they are also displayed on the liquid crystal display in different colors that correspond to their respective congestion levels. Roads are then displayed if of a type allowed by the scale of reduction.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a navigation system according to one embodiment of the present invention; and FIG. 1(A) is a functional block diagram of the CPU in FIG. 1(A);

FIG. 2 is a diagram illustrating communication between the navigation system and a road traffic information center (VICS®);

FIG. 3 is a main flowchart of a congestion information display routine (program) that the navigation system executes for display of congestion information when the map display area is a wide area display reduced to a specified scale or smaller;

FIG. 4 is a flowchart of a sub-routine for area information display in the routine of FIG. 3;

FIG. 5 is a continuation of the flowchart of FIG. 3;

FIG. 6 is a diagram illustrating transition from step S115 directly to step S116 in FIG. 5;

FIG. 7 is a diagram illustrating transition from step S116 directly to step S117 in FIG. 5;

FIG. 8 is a diagram illustrating transition from step S115 directly to step S117 in FIG. 5; and

FIG. 9 is a diagram that shows an example of a congestion information display and a wide area display (1:160,000 scale diagram) at a reduced scale of 1/160,000 that is implemented at step S126.

Claims

1. A navigation system, comprising: a receiving section that receives traffic information including congestion information;a congestion information acquisition section that obtains from the traffic information, items of congestion information related to a map information display;a congestion information extraction section that extracts, from the items of congestion information obtained by the congestion information acquisition section, a congestion information group with a specified congestion level;an overlap determination area creation section that, based on road links related to the items of congestion information within the congestion information group, creates an overlap determination area that extends both transversely and longitudinally for a specified distance from the road link;a grouping section that groups the items of congestion information having overlapping determination areas;an equal congestion level area creation section that creates an equal congestion level area by connecting the overlapping determination areas of the grouped items of congestion information; anda display control section that displays the equal congestion level area superimposed on the map information display.

2. The navigation system according to claim 1, wherein the congestion information extraction section extracts the congestion information groups for a plurality of different congestion levels in sequence;the equal congestion level area creation section creates a plurality of different equal congestion level areas that respectively correspond to the congestion information groups extracted by the congestion information extraction section; andthe display control section displays the plurality of equal congestion level areas superimposed on the map information display such that the different equal congestion level areas can be distinguished from one another.

3. The navigation system according to claim 2, wherein the display control section displays mutually differentiated display colors for the plurality of types of the equal congestion level areas superimposed on the map information.

4. The navigation system according to claim 1, wherein the equal congestion level area creation section comprises:a virtual link creation section that, where the road links have overlap determination areas which do not overlap and are directly connected in a road network, creates a virtual link that joins the road links; anda joining overlap determination area creation section that, based on the virtual link, creates a joining overlap determination area that extends both transversely and longitudinally for a specified distance from the virtual link; and whereinthe equal congestion level area creation section creates an equal congestion level area by joining the joining overlap determination area with the overlap determination areas that overlap the joining overlap determination area.

5. The navigation system according to claim 2, wherein the equal congestion level area creation section comprises:a virtual link creation section that, where the road links have overlap determination areas which do not overlap and are directly connected in a road network, creates a virtual link that joins the road links; anda joining overlap determination area creation section that, based on the virtual link, creates a joining overlap determination area that extends both transversely and longitudinally for a specified distance from the virtual link; and whereinthe equal congestion level area creation section creates an equal congestion level area by joining the joining overlap determination area with the overlap determination areas that overlap the joining overlap determination area.

6. The navigation system according to claim 3, wherein the equal congestion level area creation section comprises:a virtual link creation section that, where the road links have overlap determination areas which do not overlap and are directly connected in a road network, creates a virtual link that joins the road links; anda joining overlap determination area creation section that, based on the virtual link, creates a joining overlap determination area that extends both transversely and longitudinally for a specified distance from the virtual link; and whereinthe equal congestion level area creation section creates an equal congestion level area by joining the joining overlap determination area with the overlap determination areas that overlap the joining overlap determination area.

7. The navigation system according to claim 1, wherein the display control section, when the map information display is reduced to a scale predetermined for a wide area display, superimposes the equal congestion level area on the map information display.

8. The navigation system according to claim 2, wherein the display control section, when the map information display is reduced to a scale predetermined for a wide area display, superimposes the equal congestion level area on the map information display.

9. The navigation system according to claim 3, wherein the display control section, when the map information display is reduced to a scale predetermined for a wide area display, superimposes the equal congestion level area on the map information display.

10. The navigation system according to claim 4, wherein the display control section, when the map information display is reduced to a scale predetermined for a wide area display, superimposes the equal congestion level area on the map information display.