Graph Object Mapping via Closure Graphs and Anchor Nodes
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Solution Overview
Problem
Existing navigation systems face challenges in mapping objects from one graph to another, particularly when transitioning between different map versions or formats, as the link or roadway identifying information may not directly match, leading to inconsistencies and errors in navigation.
Innovation Solution
The method involves defining a closure graph around an identified object in the source graph, building closure sets, and identifying anchor nodes with unique junction identifiers to map objects efficiently between source and target graphs, using techniques like Dijkstra's algorithm to compute target offsets and quality descriptors for accurate mapping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If direct matching of link or roadway identifying information is used to map objects between different map versions or formats, then the mapping process is simple and fast, but the mapping accuracy deteriorates when identifying information changes (e.g., US 23 vs Claremont Ave)
Solution Approach 1:
The patent introduces closure graphs and anchor nodes as intermediary structures to facilitate mapping between source and target graphs. Instead of directly matching link identifiers, the system builds closure graphs around source objects, identifies anchor nodes (junctions with consistent identifiers across map versions), and uses these anchors to establish accurate correspondences. This intermediary approach resolves the contradiction by enabling accurate mapping without requiring direct identifier matching.
Solution Approach 2:
The patent segments the mapping process into distinct phases: building closure graphs around source objects, identifying anchor nodes within these closure graphs, and using the anchor nodes to establish correspondences. This segmentation allows the system to handle complex mapping scenarios by breaking them down into manageable steps, maintaining both accuracy and efficiency.
2Reliability
If closure graphs and anchor nodes are used to improve mapping accuracy between different graph formats, then mapping robustness improves, but the computational complexity and processing time increase
Solution Approach 1:
The patent performs preliminary actions by pre-building closure graphs around source objects and pre-identifying anchor nodes before the actual mapping operation. This preliminary preparation enables the mapping process to proceed efficiently by leveraging pre-computed structures, thus reducing the computational burden during runtime while maintaining high robustness.
Solution Approach 2:
The patent changes the parameter representation by transforming the mapping problem from direct identifier matching to a graph-based approach using closure graphs and anchor nodes. This parameter transformation enables the system to handle variations in link identifiers across map versions by focusing on the topological relationships and consistent anchor points, thereby improving robustness without proportionally increasing complexity.
3Reliability
If closure graphs are built around source objects with multiple closure sets and anchor node identification, then mapping error tolerance improves, but the processing time and computational resources increase
Solution Approach 1:
The patent implements feedback mechanisms by using consistency checks that verify whether mapped objects maintain their spatial and topological relationships. This feedback loop allows the system to detect and correct mapping errors, improving error tolerance. The feedback is integrated into the mapping process in a way that validates results without requiring excessive computational resources or time.
Data Source
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AI summary
Methods, apparatus, and computer program products are provided. An example method comprises identifying an object in a source graph; defining a closure graph around the object in the source graph; building a closure set around the object based on the closure graph; identifying the anchor nodes of the closure set on the target graph; and deflating the closure set on the target graph to identify a target object in the target graph that corresponds to the object in the source graph. The object is identified by a directed way and an offset there along. An anchor node is a junction that is tagged with a junction identifier configured to uniquely identify the junction in both the source graph and a target graph.