Hierarchical Map Matching for High-Speed Road Identification
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Solution Overview
Problem
Conventional map matching methods in traffic information systems are inefficient due to high processing times, especially when dealing with large areas and numerous candidate points, leading to increased maintenance workloads and errors in road position identification.
Innovation Solution
Implementing a hierarchical layer structure for road network data, where priority is given to roads with higher weights or upper-grade layers, and relaxing restrictions to broaden the matching range when necessary, allowing for rapid identification of objective roads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional map matching methods process all roads in large areas with numerous candidate points, then comprehensive road position identification is achieved, but processing time increases significantly
Solution Approach 1:
The patent segments the road network into multiple hierarchical layers based on road types and importance levels. The map matching process is divided into sequential stages, where each layer is processed in order from highest to lowest priority. This segmentation allows the system to focus computational resources on the most important roads first, significantly reducing overall processing time while maintaining identification accuracy.
Solution Approach 2:
The patent performs preliminary filtering of candidate roads by pre-classifying roads into hierarchical layers before the actual map matching operation. By organizing the road network structure in advance and establishing priority relationships, the system eliminates the need to process all candidate points equally during the matching phase, thereby reducing computational burden and processing time.
2Measurement precision
If strict matching restrictions are applied to identify objective roads, then identification accuracy is improved, but the matching range is limited and processing becomes slower
Solution Approach 1:
The patent implements dynamic matching restrictions that adapt based on the current processing layer and candidate point evaluation results. The restriction level is not fixed but adjusts during the matching process - starting with stricter restrictions for high-priority layers and relaxing them for lower-priority layers or when candidate points are insufficient. This dynamic approach balances accuracy requirements with processing efficiency.
Solution Approach 2:
Different matching restriction criteria are applied to different hierarchical layers of roads. High-priority roads (e.g., expressways, national roads) undergo more stringent matching verification, while lower-priority roads use more relaxed criteria. This local differentiation of quality standards allows the system to maintain high accuracy for critical roads while processing less important roads more quickly.
3Reliability
If all road networks are processed in detail, then complete map matching coverage is achieved, but maintenance workloads increase
Solution Approach 1:
The patent segments the road network maintenance task into hierarchical layers, where each layer corresponds to a specific road type or importance level. This segmentation allows maintenance operations to be performed selectively - updating or verifying only the necessary layers based on current needs, rather than processing the entire road network uniformly. This significantly reduces maintenance workload while maintaining overall system reliability.
Data Source
AI summary
An object of the present invention is to provide a map matching method capable of performing a process operation in a high speed. In the map matching method of the present invention, while employing road network data in which road networks are formed in a plurality of hierarchical layers “a”, “b”, “c”, and a road network of an upper-grade hierarchical layer is established by such a road network which is extracted from a road network having a lower-grade hierarchical layer lower than the road network having the upper-grade hierarchical layer, a road network of the uppermost-grade hierarchical layer “a” is matched with a shape vector indicative of a shape of a objective road in a beginning stage; and when such a candidate road which is matched with the shape vector cannot be obtained in the road network of the uppermost-grade hierarchical layer “a”, since such a road network having another hierarchical layer “b”, or “c” is matched with the shape vector, the objective road is identified. In the most cases, as to a objective road of traffic information and the like, the objective road can be identified by executing a map matching operation with employment of the road network having the uppermost-grade hierarchical layer “a”, and the map matching operation can be carried out in a high speed.