Self-intersection mode identification and processing method for multi-ring polygon

Abstract

The invention discloses a self-intersection mode identification and processing method for a multi-ring polygon. The method comprises the steps of obtaining nodes and line segments, forming the multi-ring polygon, in the multi-ring polygon, carrying out identification in the anticlockwise direction, and obtaining an outer ring and an inner ring of the multi-ring polygon; and calculating a minimum bounding rectangle of each line segment, establishing an R tree index, identifying all minimum bounding rectangles which are intersected with the minimum bounding rectangle of a certain line segment, forming a plurality of minimum bounding rectangle pairs, putting the minimum bounding rectangle pairs into a to-be-processed candidate set of the line segment. The method has the advantages that the types of self-intersection modes of the multi-ring polygon are refined according to a spatial relationship among elements forming the self-intersection modes, and topology and distance relationships among the elements are utilized to realize automatic identification of different types of self-intersection modes; and various self-intersection modes of the multi-ring polygon are processed by using shift and retraction algorithms considering conflict areas and minimum visual distance constraints, so that a processing result is ensured to meet topology, shape consistency and visual distinguishability at the same time.

Description

technical field [0001] The invention relates to the technical field of cartography, in particular to a multi-ring polygon self-intersecting pattern recognition and processing method. Background technique [0002] Polygon self-intersection is a special form of intersection calculation, and it is also a key factor affecting data quality. Usually, polygon self-intersections occur in data operations that significantly change the shape of polygons, such as space superposition operations, map comprehensive transformations, etc. Although the number of polygon self-intersections is very small in one calculation, it will cause obvious topological errors. And directly make subsequent map operations down, so it is very important to efficiently and accurately detect polygon self-intersections and process them into simple polygons. [0003] In computational geometry, a polygon refers to a closed connected area surrounded by a group of nodes (more than 2) connected sequentially in a cert...

AI Technical Summary

Problems solved by technology

In fact, multi-ring polygon self-intersection and boundary line segment self-intersection are two completely different situations. Polygon self-intersection processing based on line segment self-intersection cannot take into account the spatial relationship between inner and outer rings and visually distinguishable features, resulting in identifiable The type of self-intersection is very limited, and there are still obvious topological errors and space occupancy conflicts in the processing results

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