Geocode Trie for Reverse Geocoding Overlapping Polygons
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Solution Overview
Problem
Traditional reverse geocoding methods, such as QuadTree structures, face inefficiencies when dealing with overlapping geometries, leading to high latency and resource usage due to garbage collection overhead in programming languages like Java, particularly in solving the 'point-in-polygon' problem.
Innovation Solution
A geocode trie structure is constructed using variably sized tiles defined by geohash values, where each tile's size depends on the granularity of the geohash, allowing for efficient reverse geocode lookups by traversing the trie based on a geohash input value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If QuadTree structure is used for reverse geocoding, then geometry representation is achieved, but multiple geometries are returned for overlapping areas causing point-in-polygon problem
Solution Approach 1:
The patent segments the geographic space into a hierarchical tile structure where each tile represents a specific geographic area at a particular zoom level. This segmentation allows the system to divide the complex problem of reverse geocoding into manageable spatial units, eliminating the need to handle overlapping geometries by providing a clear hierarchical path from coarse to fine granularity.
Solution Approach 2:
The patent introduces a zoom level dimension to the traditional spatial index, creating a multi-dimensional tile structure. By adding this temporal/spatial dimension, the system can represent the same geographic area at different levels of detail without overlap, transforming the 2D spatial problem into a 3D hierarchical structure that naturally resolves the point-in-polygon ambiguity.
2Ease of operation
If traditional reverse geocoding methods are used, then location lookup is performed, but high latency and resource usage occur due to garbage collection overhead
Solution Approach 1:
The patent pre-computes and stores the hierarchical tile structure and associated geometry mappings during an offline indexing phase. By performing this complex computation in advance, the runtime lookup operation only needs to traverse the pre-built hierarchy, dramatically reducing latency and avoiding garbage collection overhead during critical lookup operations.
Solution Approach 2:
The patent creates a simplified copy of the geographic data in the form of a hierarchical tile index, which captures the essential spatial relationships without the full complexity of the original geometry data. This copy allows for fast lookup operations while the original data remains unchanged, separating the indexing burden from the query performance.
3Reliability
If overlapping geometries are handled with multiple solutions, then point-in-polygon matching is attempted, but substantial inefficiency and resource requirements result
Solution Approach 1:
Instead of taking a point and determining which polygon it falls into (point-in-polygon), the patent inverts the approach by organizing space into non-overlapping tiles and using the tile hierarchy to directly identify the containing geometry. This inversion eliminates the computational complexity of point-in-polygon algorithms by providing a direct hierarchical path to the answer.
Data Source
AI summary
A method and system generates a model of a geographic area for use in identifying locations of the geographic area. A set of variably sized tiles is defined for each of a set of overlapping geometries in the geographic area. Each of the variably sized tiles is defined by a geohash, where the size of the tile is dependent on a granularity of the geohash. A geocode trie structure representing the variably sized tiles can be constructed and used to map one or more provided location coordinates to at least one of the geometries represented by the tiles.