Data processing: vehicles – navigation – and relative location – Navigation – Employing position determining equipment
Reexamination Certificate
2001-10-01
2003-09-16
Cuchlinski, Jr., William A. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Navigation
Employing position determining equipment
C701S200000, C701S211000, C340S990000, C340S950000
Reexamination Certificate
active
06622085
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a map image processing technique which handles road map data, and more particularly to a device and method for preparing road map data.
BACKGROUND ART
Electronic map techniques in which a computer is used to display electronic map image data on a screen are utilized in various applications including car navigation. In cases were roads are displayed on ordinary maps, there is no problem if the roads are drawn as simple lines ignoring the width of the roads in the case of small-scale maps such as large-area maps. However, in the case of large-scale maps such as detailed city maps, roads must be expressed as regions that have an accurate width dimension. Naturally, in the case of electronic maps as well, various road data preparation methods and display methods have been developed for the purpose of expressing roads with a width dimension. For example, the methods described in Japanese Patent Application Kokai No. Sho 62-80774, Japanese Patent Application Kokai No. Hei 4-303271, Japanese Patent Application Kokai No. Hei 4-303272 and Japanese Patent Application Kokai No. Hei 6-83931, etc., are known.
In the graphic processing device described in Japanese Patent Application Kokai No. Sho 62-80774, the trouble involved in drawing roads by the manual setting one at a time of straight lines that constitute road outlines in the preparation of road maps that show a width dimension in the roads is eliminated as follows: specifically, when the drawer sets the road width at the starting point and final point of a road, a pair of parallel lines that run from the starting point to the final point while maintaining a spacing that corresponds to the road width are drawn, and in cases where a given pair of parallel lines crosses another pair of parallel line, the parallel lines at the point of intersection are automatically erased. Accordingly, road maps with a width dimension that encompasses intersections can easily be prepared.
In the device described in Japanese Patent Application Kokai No. Hei 4-303271, when a person sets the road width and draws a reference line with a cursor, a pair of parallel lines are drawn that run along this reference line while maintaining a spacing that corresponds to the road width.
In the device described in Japanese Patent Application Kokai No. Hei 4-303272, when two road s that are respectively expressed as pairs of parallel straight lines partially overlap each other at an angle, the parallel lines are amended in the overlapping area s o that a turning angle is drawn.
In the device described in Japanese Patent Application Kokai No. Hei 6-83931, when two roads that are respectively expressed by pairs of parallel lines are connected with each other, the connecting parts between the roads are drawn using pairs of parallel straight lines and arc-form lines.
Thus, in the prior art, road data is expressed by pairs of parallel lines. However, actual road shapes are extremely complex, and the accurate expression of such shapes by means of pairs of parallel lines alone is absolutely impossible. Especially in the case of extremely large-scale city maps in which center dividers, sidewalks and traffic lanes, etc., are accurately drawn, conventional road data preparation techniques using pairs of parallel lines are completely useless.
Furthermore, in the case of electronic city maps, there is a demand for a system that allows the automatic painting in of roads with colors or textures. In the case of paper-based city maps, roads may be made easily visible by coloring the roads with colors that are different from those of other regions. In electronic maps as well, roads are naturally easier to see if these roads are colored with specified colors. In order to achieve automatic painting in of roads, the roads must be expressed by open-loop polygonal data However, conventional road data is merely a collection of simple line segments such as parallel lines and arc-form lines, etc. As a result, the painting in of roads cannot be performed automatically. Accordingly, in conventional electronic city maps, buildings, etc., expressed by polygons are painted in with specified colors, while roads are merely indicated by drawing the outlines of the roads, with no special coloring being applied.
Furthermore, electronic maps can provide convenient functions such as alterations in scale and street search, etc. For example, in car navigation systems, a method of use is possible in which a street search is performed and a route is displayed on a map, with the vehicle being caused to run along this route; during this operation, a small-scale large-area map is displayed while the vehicle is running on high-speed roadways, and when the vehicle enters an urban area, the display is switched to a large-scale city map. In this case, if the route found as a result of the search runs along (for example) road A, then the route must be displayed on the same road A in both the large-area map and city map. Accordingly, it is necessary that there be a logical connection between the respective roads on the large-area map and the same roads on the city map. Generally, in the case of large-area maps, it is sufficient if roads are expressed as simple lines; accordingly, the road data in such a case is road network data in which points of intersection are expressed as nodes, and roads are expressed as vector data connecting these nodes. In the case of city maps, on the other hand, the road data is a collection of road outline line-segment data such as pairs of parallel lines and arc-form lines, etc., indicating the outlines of roads (as was described above). Conventionally, an association has been established between roads shown on city maps and roads shown on large-area maps by causing the center coordinates of intersections on city maps to correspond to the nodes of the road network data on large-area maps. As a result, however, even on city maps, routes found as a result of searching are simply expressed as zigzag lines connecting the center points of intersections; in such a case, it cannot be said that the advantages of city maps, which show road configurations in detail, are sufficiently obtained.
Accordingly, an object of the present invention is to accomplish the automatic preparation of road data which shows accurate agreement with complex road configurations.
A further object of the present invention is to accomplish the automatic preparation of road data using polygonal-shape data which paints in roads that have a width dimension.
Still a further object of the present invention is to accomplish the automatic preparation of road data which is associated with road network data used in large-area maps, and which accurately expresses the road configurations used in city maps.
Still a further object of the present invention is to solve several concrete technical problems described below, which arise in the development of practical techniques for achieving the abovementioned objects.
DISCLOSURE OF THE INVENTION
In the road data preparation device of the present invention, (1) simple road polygons which encompass roads that have a width dimension in city map data are produced from road network data in which intersections are expressed as nodes and roads are expressed as links that connect these nodes, (2) scissors data which defines the outlines of roads is prepared from city map data, and (3) road polygon data which is shaped into the shapes of roads in the city map data is prepared by trimming the simple road polygons along the outlines defined by the scissors data. As a result, the roads having complicated shapes in the city map are expressed as polygons.
In a preferred embodiment of the present invention, when a plurality of independent simple road polygons are prepared for a single link in the preparation of simple road polygons, these simple polygons are distinguished as external polygons that correspond to the external shapes of roads, and cut-out polygons that correspond to cut-out areas of roads. In this way, roads with loop shapes that have cut-o
Amita Junya
Hattori Yaheiji
Kishikawa Kiyonari
Kobayashi Hiroki
Cuchlinski Jr. William A.
Gallagher & Lathrop
Gibson Eric M
Hitachi Software Engineering Co. Ltd.
Lathrop, Esq. David N.
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