Device and method for creating and using data on road map expressed by polygons

Abstract

An object of the present invention is to accomplish the automatic preparation of road data in which roads and intersections are expressed by polygons that show accurate agreement with the complicated road shapes on city maps. In simple polygon preparation processing 3, the respective line segments of road network data 2 in which roads are expressed as line segments are expanded in the direction of the width dimension, thus producing simple road polygon data 4 which has a width that is slightly greater than the width of the roads in the city map data 5. Next, in scissors data preparation processing 6, scissors data 7 which defines the outlines of roads is prepared from the city map data 5 by connecting shape lines in the vicinity of roads. Next, in road polygon preparation processing 9, road polygon data 9 which shows good agreement with the shapes of roads in the city map data is prepared by trimming the simple road polygons along the road outlines defined by the scissors data.

Description

technical field [0001] The present invention relates to a map image processing technique using road map data, in particular to a road data creation device and method. Background technique [0002] Electronic map technology, which uses a computer to display digital map image data on the screen, can be used in various applications, mainly for car driving guidance. In general maps, when representing roads, it is not a problem to draw roads with simple lines regardless of their width on a small-scale map such as a wide-area map. However, in large scale maps like detailed downtown maps, roads need to show areas of the correct width. Of course, in electronic maps, various road data creation methods and display methods for displaying wide roads have been developed. For example, the methods described in JP-A-62-80774, JP-A-4-303271, JP-A-4-303272 and JP-A-6-83931 are known. [0003] In the graphics processing device described in JP-A-62-80774, when making a road map with a width,...

AI Technical Summary

Problems solved by technology

However, as a result, the explored route is simply represented by a polyline connecting the center points of intersections even on a city map, and the advantages of a city map that shows the shape of roads in detail cannot be fully utilized.

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