Pattern-Based Map Matching for Ambiguous Road Links
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Solution Overview
Problem
Current map-matching technologies face challenges in accurately matching probe points to road links when links are close together and have similar geographies, leading to ambiguity and incorrect route calculations due to the inability to account for road width and geometry.
Innovation Solution
A pattern-based map matching system that queries a digital map for road links within a threshold distance of a probe point, determines a match starting point by extending a normal line from the probe point to the road link, and generates patterns such as probe heading, distance, and area patterns to select the correct road link, thereby improving accuracy by accounting for road width and geometry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional point-based map matchers are used, then the map matching process is simple and fast, but the matching accuracy deteriorates when links are close together and have similar geographies
Solution Approach 1:
The patent segments the probe trace into multiple sampled probe points and generates multiple patterns (heading pattern, distance pattern, area pattern) for each point. This segmentation allows the system to analyze different spatial characteristics separately and combine them for more accurate matching, resolving the contradiction by breaking down the complex matching task into manageable pattern comparisons.
Solution Approach 2:
The patent transitions from traditional 2D point-to-link matching to 3D spatial pattern matching by incorporating road width and geometry into the matching process. The area pattern specifically uses the third dimension (road width) to distinguish between closely spaced links, adding a new dimension of discrimination that improves accuracy without excessive complexity.
2Reliability
If traditional point-based map matchers are used, then the computational process is fast, but the ability to distinguish between similar road links deteriorates
Solution Approach 1:
The patent applies partial action by selecting a subset of sampled probe points rather than processing every single point. This selective sampling maintains processing efficiency while generating sufficient pattern data to reliably distinguish between similar road links, balancing reliability and productivity.
Solution Approach 2:
The patent introduces patterns (heading pattern, distance pattern, area pattern) as intermediary representations between the raw probe points and the final link selection. These patterns serve as mediators that transform complex spatial relationships into comparable formats, improving reliability while maintaining processing speed through efficient pattern matching.
3Measurement precision
If road width and geometry are not considered, then the map matching process remains simple, but the ability to account for spatial relationships deteriorates
Solution Approach 1:
The patent applies local quality by making each pattern (heading, distance, area) specialized for capturing specific spatial characteristics. The area pattern specifically addresses road width locally at each probe point, while the heading pattern captures directional information. This localized approach to spatial analysis improves measurement precision without requiring a complete overhaul of the matching system.
Data Source
AI summary
An approach is provided for pattern-based map matching of a probe trace to a digital map. The approach involves querying the digital map for a set of road links within a threshold distance of a probe point. The approach also involves determining a match starting point for each road link of a set of road links. The approach further involves selecting a sampled probe point from the probe trace. The approach also involves generating one or more patterns for said each road link based on the match starting point, the sampled probe point, the topology polyline, or a combination thereof. The approach further involves selecting a matched road link from among the set of road links based on the one or more patterns. The probe point is then snapped to the matched road link.