An advanced web API for isochrones calculation using OpenStreetMap data

Abstract

This chapter demonstrates a software that finally makes urban reachability analysis free, open-source, and usable for non-technical urban analysts. We aim to provide researchers with a highly-parametric API (Application Programming Interface) for creating isochrones worldwide, meeting various scenario requirements with high accuracy. We start with OpenStreetMap road data that the software cleans by applying a sub-graph algorithm, removing isolated road links. This results in a fully-connected network for isochrones calculation, improving the web API stability. Then, a non-recursive breadth-first-search algorithm runs in parallel to generate isochrone links. The isochrones are then constructed using either link buffers or concave hulls to meet various accuracy requirements. The final outputs, including isochrones polygons, lines, and nodes with traverse distance attributes, can be exported in popular formats. The API supports thousands of isochrone calculations simultaneously, and is fully accessible online. The source code will also be provided for free for anyone to take and modify.