A method and drawing device for decomposing ring-covered polygons

Abstract

Embodiments of the present invention provide a method and drawing device for decomposing a ring polygon. There is at least one simple polygon inside the ring polygon; all boundary points outside the ring polygon form an outer ring, and all boundary points of each simple polygon form an inner ring. ; The method includes: calculating each maximum value coordinate of the outer ring; obtaining the intersection points formed on the boundary of the inner ring after the cutting line cuts the inner ring, and calculating the inner points of each inner ring according to each intersection point, and the inner points are two adjacent intersection points The center point; based on the inner point and the most value coordinates, create a cutting polygon by adding auxiliary points, and the cutting polygon runs through all inner rings; perform Boolean operations on the cutting polygon and the surrounding polygon to decompose the surrounding polygon to obtain a simple polygon. The algorithm is used to decompose the ring polygon without manual participation. The whole process is automatically processed, so the operation is simple. The Boolean operation is used to decompose, which greatly reduces the number of simple polygons formed after cutting the ring polygon.

Description

technical field [0001] The invention relates to digital drawing technology, in particular to a method and drawing device for decomposing encircled polygons. Background technique [0002] In navigation electronic map drawing technology, encircled polygons are used to represent road surfaces, rivers, oceans and islands, but the physical format of electronic maps cannot support encircled polygons. [0003] In the prior art, some functions of a third-party program are used to finally decompose the ring polygon into several triangles through a combination of several steps. [0004] The existing technology has the following problems: the functions of third-party programs are difficult to integrate into the NDS compilation tool system, and the PDH compilation process, as a part of the NDS compilation tool system, requires manual intervention, and the complex operation leads to slow conversion speed; too many simple polygons are generated, which cannot Verify that it is correct. ...

AI Technical Summary

Problems solved by technology

[0005] The technical problem to be solved by the present invention is to provide a method and a drawing device for decomposing ring-covered polygons, which solve the defects that manual intervention is required in the existing compilation process, and the conversion speed is slow due to complicated operation

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