Geographic Polygon Overlap Detection via Spatial Indexing
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Solution Overview
Problem
Navigation and mapping service providers face challenges in efficiently determining overlapping polygons in geographic databases due to resource-intensive traditional methods that rely on evaluating a large number of stored polygons, leading to high computational costs and time consumption.
Innovation Solution
A method that identifies proximate polygon points within a distance threshold of a candidate polygon or point, retrieves corresponding polygons, and determines intersections to select overlapping polygons, reducing the number of polygons to process and minimizing resource usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional methods are used to evaluate all stored polygons for overlaps, then completeness of overlap detection is improved, but computational resource consumption and time increase significantly
Solution Approach 1:
The patent segments the evaluation process into two stages: first identifying candidate polygons using spatial indexing based on bounding boxes, then performing detailed overlap evaluation only on these candidates. This segmentation reduces the number of polygons requiring full evaluation while maintaining detection completeness.
Solution Approach 2:
The patent performs preliminary filtering by comparing bounding boxes before conducting full overlap evaluation. By pre-identifying candidate polygons that might overlap based on their bounding box positions, the system avoids unnecessary detailed evaluations of polygons that cannot possibly overlap, thus improving computational efficiency.
2Measurement precision
If all stored polygons are evaluated for overlap, then accuracy of overlap detection is improved, but processing time increases
Solution Approach 1:
The evaluation process is divided into candidate identification and precise overlap detection phases. Spatial indexing structures organize polygons to enable rapid candidate identification, after which accurate overlap detection is performed only on the reduced candidate set, maintaining precision while reducing time.
Solution Approach 2:
Bounding box comparisons are performed as a preliminary step to identify candidate polygons before conducting accurate overlap detection. This preliminary action filters out polygons that cannot overlap, ensuring accurate detection is performed only where necessary, thus reducing overall processing time without compromising accuracy.
3Reliability
If a large number of stored polygons are processed, then completeness of geographic database coverage is improved, but resource consumption increases
Solution Approach 1:
The patent segments the polygon set into all stored polygons and candidate polygons identified through spatial indexing. By processing only the candidate subset for detailed overlap evaluation, the system maintains complete database coverage while significantly reducing computational resource consumption.
Solution Approach 2:
Spatial indexing structures are built as a preliminary action to enable efficient candidate identification. This preliminary organization allows the system to cover the entire database while consuming fewer resources by evaluating only those polygons that are candidates for overlap, not all polygons in the database.
Data Source
AI summary
An approach is provided for determining a polygon of a geographic database that overlaps a candidate polygon or candidate point. The geographic database represents stored polygons as respective polygon points with zero area. The approach involves determining proximate polygon points from among the respective polygon points with zero area that are within a distance threshold of the candidate polygon or the candidate point. The approach also involves retrieving one or more proximate polygons from the geographic database that correspond to the one or more proximate polygon points. The approach further involves determining an intersection between the one or more proximate polygons and the candidate polygon or the candidate point. The approach then involves selecting the polygon that overlaps the candidate polygon or the candidate point based on the determined intersection.