Spatio temporal analysis of urban systems.

Isochrone and average escape velocity

the OpenTripplanner library combine the schedules of public transport (in the gtfs format) and the graph of the streets (downloaded from Openstreetmap) of a city and it is able to compute for each point of the map the isochrones. In this article we consider the isochrone at time \(t\) as the set of point of the map that are reachable within travel time \(t\) with the best combination of walk and public transports. For instance an isochrone of Paris, \(t=30min\), is shown in the figure below.