Time-Dependent Reachability Analysis: A Data-Driven Approach

An isochrone is generally defined as a curve drawn on a map connecting points at which moving objects (e.g., cars) arrive at the same time. Their construction is an important task in many application domains. As an example, in urban planning, isochrones are essential when assessing the placement of public services like hospitals and fire departments. In this study, we formally define the isochrone and reverse isochrone problems, describe our approach to solving them and provide a fully functional system that is capable of visualizing the reachability in various ways. Unlike other studies, our approach is purely data-driven and does not depend on the underlying road network for computing the isochrone. Instead, we focus on directly processing trajectory data. Our system processes two real-world taxi datasets to visualize the reachability of the cities of Seoul and Xi'an. As our experiments show, our approach outperforms the traditional graph-theory techniques while eliminating the expensive need of preprocessing the data.