Isochrone map explained

An isochrone map in geography and urban planning is a map that depicts the area accessible from a point within a certain time threshold.^[1] An isochrone (iso = equal, chrone = time) is defined as "a line drawn on a map connecting points at which something occurs or arrives at the same time".^[2] In hydrology and transportation planning isochrone maps are commonly used to depict areas of equal travel time. The term is also used in cardiology^{[3] [4] [5]} as a tool to visually detect abnormalities using body surface distribution.^[6]

History

Early examples of Isochrone maps include the Galton's Isochronic Postal Charts and Isochronic Passage Charts of 1881 and 1882,^[7] Bartholomew's Isochronic Distance Map and Chart first published 1889,^[8] and Albrecht Penck's Isochronenkarte first published 1887.^[9] Where as Galton and the Bartholomews published maps depicting the days or weeks it took to travel long distances, Albrecht further developed the idea to not only depict long distances and world travel but also smaller areas. Penck also created a series of maps that only depict the travel times of a certain transportation mode, for example Rail transport. Isochrone maps are commonly used in the UK in connection with development control.^{[10] [11] [12] [13]} Isochrones are currently typically computed by via generating shortest-path trees on network graphs, and then generating a convex hull around the accessible nodes. Increases in computation, data storage, and improvements in algorithms have facilitated the rapid generation of isochrones.^[14] Recent techniques in visualization include linking travel times to network edges to show the paths accessible from a point rather than show the area accessible from a point.

Usage

Hydrology

Isochrone and related maps are used to show the time taken for runoff water within a drainage basin to reach a lake, reservoir or outlet, assuming constant and uniform effective rainfall.^{[15] [16] [17] [18]} An early example of this method was demonstrated by Clark in 1945.^[19]

Transport planning

Isochrone maps have been used in transportation planning since at least 1887.^{[20] [21]} Isochrone maps in the context of transport planning are essentially maps of accessibility where travel time is used as the cost metric. Isochrone maps can be created for different modes of transportation,^[22] e.g. foot, bicycle, motor vehicle. Put simply, the output of an isochrone map for transport will show how far (in distance) is reachable from a start point, including the parameter of time.

Such maps for private motor transport were widely used in a 1972 study into airport accessibility in Hampshire, South East England.^[23] At that time, their use was disadvantaged by being time-consuming to create.

The term isodapane map is used to refer to a map were the contour represent transportation cost instead of transportation time.^[24]

General public

Journey time websites have been built using mapping technologies and open data.^{[25] [26]} Isochrones can be used by house hunters wishing to evaluate residential areas.^[27] An isochrone map of the London Underground network was made available in 2007.^[28]

Services and applications

Several digital tools exist which can generate isochrone maps.

openstreetmap-based solutions:^[29]

• CommuteTimeMap - lets to build and visualize isochrones worldwide
• Geoapify Isochrone API - API service to build isochrones for drive, truck, bicycle, walk and transit modes. Worldwide.
• GraphHopper https://github.com/graphhopper/graphhopper/blob/master/docs/web/api-doc.md#isochronehttps://github.com/graphhopper/graphhopper/pull/1237 can be used to calculate a detailed time information for every point within a certain time or distance reach.
• GRASS v.net.iso module
• instaGIS^[30]
• Iso4App Public Transport Isochrone maps (Isochrones based on GTFS data)
• Mapbox Isochrone API (interactive Mapbox example)
• Mapumental
• OpenRouteService Isochrones Service - uses OSM data and map, shows isochrones worldwide (no source code available)
• OpenTripPlanner - a development branch has work on an Analytics Extension, which currently provides isochrones based on the OSM network and GTFS data (source code available)
• OSRM Isochrone Generate drivetime isochrones from OSM using OSRM.
• pgRouting The creation of journey time isochrones to airports in Finland has been explained using the GIS software QGIS and pgRouting (an extension of PostGIS).^[31]
• pysochrone is a Python script and simple web interface for computing and displaying isochrones from an OGR-supported data source (e.g. PostGIS)
• Reachability Analysis An application (built using WhereOS and OSM data) which calculates reachability (isochrone) from given set of addresses.
• Safe Routes to School Mapping Toolkit - working to create travel distance/time web app for pedestrians and bicyclists using OSM data (source code available)
• TargomoAPI - Travel times, Routing, Points of Interests, Isochrones - developer tools to build state-of-the-art geospatial analytics applications, enhance location search, and personalize user experience. (Interactive Demo)
• TravelTime API^[32] Uses some OSM Data and has a free isochrone generator tool using public transport, cycling, walking, driving and combined bike & train. Available as a plugin for QGIS and ArcGIS.
• Valhalla isochrone service
• Walkscore Travel Time API - uses GTFS and OSM data for maps of Seattle, San Francisco, and Washington DC. Built on the open source Graphserver library. (no source)
• WNYC Transit Time - public transit isochrones for NYC
• Stadia Maps Isochrone API (tutorial with an interactive JSFiddle)

GTFS-based solutions:

• Mapnificent^{[33] [34]}

Proprietary data solutions:

• Google Maps API
• PedCatch

See also

• Daily urban system
• Public transport timetable
• Traffic congestion map
• Transit map
• Walking distance measure

External links

• Further Exploration #9: Isochrone Maps (Travel Time Maps)
• Travel time between American counties: 1880 and 1900

Notes and References

1. Allen. Jeff. 2018-12-01. Using Network Segments in the Visualization of Urban Isochrones. Cartographica: The International Journal for Geographic Information and Geovisualization. 53. 4. 262–270. 10.3138/cart.53.4.2018-0013. 133986477. 0317-7173.
2. Web site: Isochrones: Analysis of Local Geographic Markets . Desai . Kiran . 17 October 2008 . Mayer Brown . 2018-05-31.
3. Web site: MFS ECG Potential Map (40ms) . . March 21, 2012.
4. Book: Optical mapping of cardiac excitation and arrhythmias . . Rosenbaum, David S. . 2001 . 251 . 0879934816 . Jalife, José.
5. Activation and repolarization of the normal human heart under complete physiological conditions . Ramanathan, Charulatha . . April 2006 . 103 . 16 . 6309–6314 . 10.1073/pnas.0601533103 . 16606830 . Jia, Ping . Ghanem, Raja . Ryu, Kyungmoo . Rudy, Yoram. 1458874 . 2006PNAS..103.6309R . free .
6. Isochrone map, its implication and clinical usefulness . Miyashita, T . Nihon Rinsho: Japanese Journal of Clinical Medicine . January 1995 . 53 . 1 . 48–55 . Okano, Y . 7897854.
7. Galton. Francis. 1881. On the Construction of Isochronic Passage Charts. Proceedings of the Royal Geographical Society. Royal Geographical Society. 657. 10.2307/1800138. 1800138.
8. Book: Bartholomew. 1889. Atlas of Commercial Geography. Edinburgh. John Bartholomew and Son. S. VI, Map 13 a.
9. Penck. Albrecht. 1887. Isochronenkarte der österreichisch-ungarischen Monarchie. Deutsche Rundschau für Geographie und Statistik. 337.
10. Web site: Planning for Town Centres; Practice guidance on need, impact and the sequential approach . . December 2009 . March 26, 2012.
11. Web site: Transport Assessment; Guidelines for Development Proposals in Northern Ireland . . November 9, 2006 . March 26, 2012.
12. Web site: Technical Guidance on Accessibility Planning in Local Transport Plans . Local Transport Planning Network . March 26, 2012 . dead . https://web.archive.org/web/20071120132057/http://www.ltpnetwork.gov.uk/Documents/Document/technical%20guidance%20on%20accessibility%20planning%20in%20LTPs.pdf . November 20, 2007 .
13. Web site: Barker Review of Land Use Planning . December 2006 . March 26, 2012 . Barker, Kate. Kate Barker .
14. Bolzoni. Paolo. Helmer. Sven. Lachish. Oded. 2016. Fast Computation of Continental-Sized Isochrones. International Conference on GIScience Short Paper Proceedings. en. 1. 1. 10.21433/B31171h533kp. free.
15. A grid-based distributed flood forecasting model for use with weather radar data: Part 1. Formulation . Bell, V. A. . Hydrology and Earth System Sciences . 1998 . 2 . 2/3 . 265–281 . 10.5194/hess-2-265-1998 . . Moore, R. J.. 1998HESS....2..265B . free .
16. Book: Engineering Hydrology . Tata McGraw-Hill . Subramanya, K . 2008 . 298 . 978-0070648555 .
17. Web site: EN 0705 isochrone map . . March 21, 2012 . dead . https://web.archive.org/web/20121122145250/http://webworld.unesco.org/water/ihp/db/glossary/glu/EN/GF0705EN.HTM . November 22, 2012 .
18. Web site: Isochrone map . https://archive.today/20130113224827/http://www.websters-dictionary-online.org/definitions/Isochrone+map . dead . January 13, 2013 . Webster's Online Dictionary . March 21, 2012 .
19. Web site: Unit Hydrograph (UHG) Technical Manual . . March 21, 2012.
20. Web site: October 2013. Mapping Manchester project. May 5, 2014.
21. Web site: 1911. Dissertation of Johannes Riedel. Thomas & Hubert .
22. Defining isochrones in multimodal spatial networks . March 21, 2012 . Gamper Johann . Proceedings of the 20th ACM international conference on Information and knowledge management . 2011 . . Glasgow . Böhlen, Michael . Cometti, Willi . Innerebner, Markus . 10.1145/2063576.2063972 . 9781450307178.
23. A Network Analysis of Airport Accessibility in South Hampshire . Armstrong, H. W. . Journal of Transport Economics and Policy . September 1972 . 6 . 3 . 294–307 . 0022-5258.
24. Book: Barthwal, R. R.. Industrial Economics: An Introductory Text Book. 2007. New Age International. 9788122412789. en.
25. News: Looking for the best commuter route to Salford Quays? Stefan in Berlin can help with that . . June 7, 2011 . March 22, 2012 . June 14, 2011 . https://web.archive.org/web/20110614083727/http://menmedia.co.uk/manchestereveningnews/news/s/1422955_looking-for-the-best-commuter-route-to-salford-quays-stefan-in-berlin-can-help-with-that . dead .
26. News: Greater Manchester datastore launched . . February 24, 2011 . March 22, 2012 . Hartley, Sarah.
27. News: November 25, 2009. House-hunting goes hi-tech. The Independent. March 22, 2012.
28. Web site: Getting about – Isochrone map of London Underground . howtodobusiness.com . July 25, 2007 . March 21, 2012 . DrAlanRae . https://web.archive.org/web/20120417234937/http://blog.howtodobusiness.com/2007/07/25/getting-about-isochrone-map-of-london-underground/ . April 17, 2012 . dead .
29. Web site: Isochrone - OpenStreetMap Wiki. 2021-09-09. wiki.openstreetmap.org. Text was copied from this source, which is available under a Creative Commons Attribution-ShareAlike 2.0 Unported license.
30. Web site: instaGIS: Discovering Isochrones. 1 September 2014. instaGIS.
31. Web site: Drive Time Isochrones – An Example Using Finnish Airports . February 12, 2011 . March 22, 2012 . Graser, Anita.
32. Web site: Contributor. G. I. S.. 2016-07-09. Using the TravelTime Search API to Generate an Isochrone. 2020-06-22. GIS Lounge. en-US.
33. News: N.B.. Jun 5, 2011. A time-based transit map. The Economist. London. March 22, 2012.
34. News: O'Brien, Terrence. August 5, 2011. Mapnificent visualizes public transportation travel time, is more exciting than it sounds. Engadget. March 22, 2012.