Road Node Map Reachable Area Calculation
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Solution Overview
Problem
Existing methods for calculating a reachable area based on a road network are inefficient and costly, failing to consider the user's movement along a road network and obstacles like landforms, resulting in slow inquiry times, such as over 500 ms in the Beijing area.
Innovation Solution
A method that acquires a user's current location and road network map, generates a road node map, and determines a reachable area by searching for boundary points along the road network within a maximum travel distance, forming a convex polygon to define the reachable area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a road network-based reachable area calculation method is used, then the accuracy and realism of the reachable area determination is improved, but the calculation efficiency deteriorates (calculation time exceeds 500 ms)
Solution Approach 1:
The patent segments the road network into discrete road nodes and edges, transforming the continuous road network map into a graph structure. This segmentation enables efficient computation by breaking down the complex reachable area calculation into discrete pathfinding operations between nodes, resolving the contradiction between accuracy and efficiency.
Solution Approach 2:
The patent performs preliminary actions by pre-processing the road network map into a road node map structure before actual reachable area queries. This pre-processing organizes the data in an optimal format for rapid calculation, allowing the system to achieve both high accuracy in reachable area determination and improved calculation efficiency.
2Productivity
If a concentric circle or rectangle is used as reachable range, then the calculation efficiency is improved, but the accuracy of reachable area determination deteriorates (ignores road network constraints and landform obstacles)
Solution Approach 1:
The patent changes the fundamental parameter representation from simple geometric shapes (circles, rectangles) to a road network graph structure with nodes and edges. This parameter transformation enables the system to respect actual road constraints and landform obstacles while maintaining calculation efficiency through graph-based pathfinding algorithms.
Solution Approach 2:
The patent replaces the mechanical geometric approximation method (concentric circles/rectangles) with a computational graph theory approach. By substituting the physical geometric construction with algorithmic pathfinding on a road node map, the system achieves both efficiency and accuracy in reachable area determination.
Data Source
AI summary
A method and apparatus for determining a reachable area based on a road network are provided. The method comprises: acquiring a current location of a user and a road network map; generating a road node map based on the road network map; searching on the road node map for a boundary point extending for a maximum travel distance starting from the current location of the user along a road; and determining a reachable area based on the searched boundary point.