[Editor's note: Detailed maps help understand transportation time between point A and B. Network topology routing provided by open source software and then pushed out as a Google Maps mashup. WalkScore was previously featured here for their "walkability" maps which both help people figure out where to live.]
Republished from Google Maps Mania and Walk Score.
WalkScore have produced a Google Map mashup that can show you how far you can travel in San Francisco, Portland or Seattle on public transport in 15, 30 and 45 minutes. The map can show you how far you can travel on public transit from a given location and at any time of day.
How it Works
Transit schedules are downloaded in GTFS format and the XML street data is fetched from OpenStreetMap. These are compiled into a graph for use by the Graphserver trip planner. Street intersections are graph vertices and streets are graph edges.
Graphserver calculates the shortest path tree for a given location. The time of arrival at all street intersections is cross-referenced with a table of street intersection locations to create the contours for different travel times.