Digital map data processing system

• US 20070226243A1
• Filed: 03/16/2006
• Published: 09/27/2007
• Est. Priority Date: 03/23/2005
• Status: Active Grant

• Current Assignee: Zenrin Company Limited (Zenrin)
• Original Assignee: Zenrin Company Limited (Zenrin)
• Inventors: Shibata, Osamu, Tanaka, Kenichiro, Fuki, Tetuzo, Kondoh, Kunihiro
• Granted Patent: US 7,508,400 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01C 21/3819 Road shape data, e.g. outline of a route
• CPC Class Codes: G01C 21/3867 Geometry of map features, e.g. shape points, polygons or for simplified maps

Abstract

The digital map data processing system of the invention aims to improve the appearance of a map without increasing the labor in automatic generation of road polygons required for generation of map data.

The digital map data processing system of the invention reads network data 40, which expresses multiple roads by nodes and links, and generates polygon data 50 including road polygons by processing the network data 40. The road polygon generation process includes generation of rectangular polygons of specified widths about respective links, generation of edge lines around polygons, and elimination of unnecessary edge lines. The digital map data processing system selectively applies a suitable terminal processing technique to specify terminal geometry of each object polygon, based on connection with each connection polygon and geometries and attributes of the object polygon and the connection polygon. This desirably improves the appearance at a connection of adjacent polygons.

Claims

1. A digital map data processing system that generates map data for drawing a map, said digital map data processing system comprising:

a base data input module that inputs geometric data and attributes required for specification of geometry of multiple road polygons, which are used to draw roads included in the map data; and

a polygon data generation module that selects one of multiple terminal processing techniques to be applied for specification of terminal geometry of each road polygon, based on at least part of attributes of an object road as a processing target and a connection road to be connected to the object road, geometry of the object road and the connection road determined by the input geometric data, and directions of the object road and the connection road,

said polygon data generation module applying the selected terminal processing technique to specify the terminal geometry of each road polygon according to the geometric data and generating polygon data required for drawing the road polygons.

2. A digital map data processing system in accordance with claim 1, wherein the geometric data comprises network data that represents connection of plural roads by means of nodes and links, and

said polygon data generation module defines the geometry of each road polygon about one link by the specified terminal geometry of the road polygon and side lines of the road polygon given as sets of points located at preset distances about the link.

3. A digital map data processing system in accordance with claim 1, wherein said polygon data generation module selects the terminal processing technique, based on a result of comparison between road classes of the object road and the connection road.

4. A digital map data processing system in accordance with claim 3, wherein when there are plural connection roads relative to one object road, said polygon data generation module changes over conditions for the selection of the terminal processing technique between a case where all the plural connection roads and the object road are included in an identical road class and any other case.

5. A digital map data processing system in accordance with claim 3, wherein when there are plural connection roads relative to one object road, said polygon data generation module changes over conditions for the selection of the terminal processing technique between a case where any of the plural connection roads and the object road are included in an identical road class and any other case.

6. A digital map data processing system in accordance with claim 1, wherein said polygon data generation module selects the terminal processing technique, based on at least either a result of comparison between widths of the object road and the connection road and a connection angle between the object road and the connection road.

7. A digital map data processing system in accordance with claim 1, wherein the multiple terminal processing techniques include a technique of defining the terminal geometry of a road polygon representing the object road by a line segment that interconnects cross points of side lines of the object road and side lines of the connection road.

8. A digital map data processing system in accordance with claim 1, wherein the multiple terminal processing techniques include a technique of defining the terminal geometry of a road polygon representing the object road by a polygonal line that interconnects side lines of the object road to express the object road as a convex polygon.

9. A recording medium that stores a computer program executed to generate digital map data for drawing a map,

said computer program comprising:

a subprogram of inputting geometric data and attributes required for specification of geometry of multiple road polygons, which are used to draw roads included in the map data;

a subprogram of selecting one of multiple terminal processing techniques to be applied for specification of terminal geometry of each road polygon, based on at least part of attributes of an object road as a processing target and a connection road to be connected to the object road, geometry of the object road and the connection road determined by the input geometric data, and directions of the object road and the connection road; and

a subprogram of applying the selected terminal processing technique to specify the terminal geometry of each road polygon according to the geometric data and generating polygon data required for drawing the road polygons.

10. A digital map data processing system that generates map data for drawing a map, said digital map data processing system comprising:

a base data input module that inputs geometric data and attributes required for specification of geometry of multiple road polygons, which are used to draw roads included in the map data;

a grouping module that groups at least part of the multiple road polygons according to a preset rule; and

a polygon data generation module that generates polygon data required for drawing the road polygons from the geometric data, based on a result of the grouping.

11. A digital map data processing system in accordance with claim 10, wherein the geometric data comprises network data that represents connection of plural roads by means of nodes and links, and

said polygon data generation module defines the geometry of each road polygon about one link by the specified terminal geometry of the road polygon and side lines of the road polygon given as sets of points located at preset distances about the link.

12. A digital map data processing system in accordance with claim 10, wherein said grouping module utilizes at least either of a name of each road represented by each road polygon and a traffic regulation set on the road for the grouping.

13. A digital map data processing system in accordance with claim 10, wherein the attributes include a road class of each road represented by each road polygon, and

said grouping module sets road polygons of an identical road class in one group.

14. A digital map data processing system in accordance with claim 10, wherein said grouping module utilizes connection angles of the multiple road polygons for the grouping.

15. A digital map data processing system in accordance with claim 10, wherein said polygon data generation module comprises:

an edge line processing module that adds edge line data, which represents an edge line of each road represented by each road polygon, to the road polygon,

said edge line processing module generates the edge line data such that road polygons set in one group have a continuous edge line.

16. A recording medium that stores a computer program executed to generate digital map data for drawing a map,

said computer program comprising:

a subprogram of inputting geometric data and attributes required for specification of geometry of multiple road polygons, which are used to draw roads included in the map data;

a subprogram of grouping at least part of the multiple road polygons according to a preset rule; and

a subprogram of generating polygon data required for drawing the road polygons from the geometric data, based on a result of the grouping.