Road localisation in GrabMaps

This post details the implementation of a road localization system for GrabMaps. The core technical contribution is the use of geohashes as a proxy to approximate geographical areas and localize road segments, significantly reducing computational cost compared to direct geometric inclusion tests. The process involves precomputing geohashes for areas and then assigning roads to these geohashes. The post also discusses precision tradeoffs, exploring solutions like increasing geohash precision, calculating geohash coverage percentage, and using border shapes for geohashes near boundaries to improve accuracy.