Wednesday, May 28, 2014

Minard Flow Maps

There are numerous ways of visualizing data on maps. Heat maps, scatterplots, dot maps and scaled map markers are all popular methods of geographically visualizing data volumes. One method that seems far less popular is the flow map, as popularized by the British economic cartographer Charles Joseph Minard.

I have seen a number of attempts to recreate Minard's famous flow map of Napolean's March on Moscow. However I can't remember seeing flow maps being used in many other contexts in the world of interactive maps.

This Esri Story Map of Minard's March on Moscow is a neat narrated map of the important events during Napolean's military campaign. Unfortunately there seems to be a bug in the map that prevents the map tiles being shown when the map is zoomed out. This means that you have to keep zooming in on the map to view the map tiles.

If you want to see a zoomed out mapped visualization of Minards' flow chart you can check out Napoleon's March. This Leaflet reworking of Minard's flow map is a good attempt at an interactive map visualization of Napoleon's army movements and dwindling size. Unfortunately this map lacks Minard's temperature chart that visualized the freezing temperatures faced by Napoleon's army as they pushed eastwards.

Charles Joseph Minard also created a flow map of British coal exports in the year 1864. This Esri map is a faithful interactive reproduction of this lesser known Minard flow map. English Coal Exports 1864 shows the countries where Britain exported coal to and the quantities exported to each country. The width of the lines on the map represent the quantities of coal exports for each part of the route.

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