Graph Data Stitching for Offline Route Computation
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Solution Overview
Problem
Navigation systems face difficulties in determining routes between geographic regions with different data versions, as incompatible preprocessing of travel segment network data can hinder offline route calculations using fast search algorithms like contraction hierarchies.
Innovation Solution
The method involves accessing and stitching graph data from different geographic regions, preserving nodes associated with boundary segments using reach values, and preprocessing graph data to ensure visitation of relevant nodes during a search, allowing for efficient route computation even between regions with different data versions without requiring network connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If graph data from different geographic regions with different data versions is used for routing, then route computation can be performed offline without network connectivity, but incompatible preprocessing of the graph data can hinder the effectiveness of fast search algorithms like contraction hierarchies
Solution Approach 1:
The patent segments the graph data into multiple versions and introduces version identifiers to track and manage different data versions. This segmentation allows the routing system to handle multiple data versions independently while maintaining compatibility through the version tracking mechanism, resolving the conflict between offline computation capability and data version compatibility.
Solution Approach 2:
The patent changes the parameter of graph node representation by adding version identifiers and reach values as new attributes. These parameter changes enable the routing algorithm to distinguish between different data versions and apply appropriate preprocessing, allowing fast search algorithms to work effectively across multiple data versions without requiring network connectivity for updates.
2Loss of time
If contraction hierarchies preprocessing is applied to speed up route calculation, then routing computation becomes faster, but the preprocessing must be compatible across different data versions which is difficult to maintain
Solution Approach 1:
The patent performs preliminary action by precomputing and storing reach values for nodes during the contraction hierarchies preprocessing phase. These precomputed reach values are stored with version identifiers, allowing the system to quickly determine compatibility without re-preprocessing. This preliminary computation enables fast route calculation while maintaining compatibility across data versions through version-aware reach value comparison.
3Productivity
If boundary segments are preserved in graph data based on reach values, then the number of nodes to visit during search is reduced, but ensuring visitation of relevant nodes across different data versions becomes more complex
Solution Approach 1:
The patent introduces version identifiers as an intermediary mechanism that mediates between boundary segment preservation and data version compatibility. The version identifiers act as a bridge that allows the system to track which boundary segments are valid in which data versions, enabling efficient search by preserving only relevant boundary segments while managing version complexity through the intermediary version tracking system.
Data Source
AI summary
Systems and methods are provided for the determination of routes from, for instance, travel segment network data associated with different data versions. More particularly, a request can be received for a route from an origin to a destination. Graph data modeling a travel segment network for a geographic region associated with the origin and for a geographic region associated the destination can be accessed. The graph data can preserve boundary nodes for visiting during a search (e.g. a contraction hierarchies style search) for a shortest path through the graph data. The reach value of a boundary segment can be considered in identifying boundary segments to be visited during the shortest path search through the graph data. The route can be determined based at least in part on the shortest path.