South China Sea has recently garnered increased media attention due to China reclaiming land and building an airfield on Fiery Cross Reef. The territorial dispute regarding Spratly Islands has been simmering since the 1970ies when oil was discovered in the region. South China Sea is also “one of the busiest shipping lanes in the world” with “more than half of the world’s supertanker traffic, by tonnage, pass[ing] through the region’s waters every year” (Wikipedia).

The Department of Energy has two interesting maps on their beta website showing LNG and crude oil transport for 2011.

Transport of liquefied natual gas (LNG) in trillions of cubic feet in the South China Sea:

Transport of petroleum in millions of barrels per day in the South China Sea in 2011:


(both maps from eia.gov website)

These are ‘Sankey-inspired maps’ rather than exact Sankey diagrams. Arrow widths are not maintained where the shipping routes pass through narrow straits. Nevertheless, transport volumes are generally on a correct scale.

Martin Grandjean digitized and vectorized Charles Joseph Minard’s World Map of Migration from 1862. His recent post reminds us that no too long ago migrants were also moving from Europe to other places of the world.

via martingrandjean.ch – full vectorized image 2 MB here

The map, based on data for the year 1858, “shows migration flows that contrast with the maps of the twenty-first century. That year, 86.000 Englishmen left their country, as 45.300 Germans, 20.000 French and 11.600 Portuguese.”

Read this interesting post from the Cartographia blog for additional detail on the map.

From a technical point of view, the only criticism I have of Minard’s map is that the direction of the arrows is not indicated. It requires the reader to know about origins or destinations of migration.

You can see the original Minard migration map (“Carte figurative et approximative représentant pour l’année 1858 les émigrants du globe, les pays dóu ils partent et ceux oú ils arrivent”) in this 2009 post and at Wiki Commons or directly at the Library of Congress.

You might want to check out another related June 2015 article by Martin Grandjean, where he points out some shortcomings of migration maps.

The 2012 GEA Global Energy Assessment report (GEA Global Energy Assessment – Toward a Sustainable Future, Cambridge University Press, Cambridge UK and New York, NY, USA and the International Institute for Applied Systems Analysis, Laxenburg, Austria) features five maps showing energy trade in the world on pages 128/129.

These can almost be considered Sankey diagrams, so I am featuring them here on the blog.

This one is for embodied energy in trade goods.

And this one is a classic oil and oil product trade flows map:

Flows lead from a specific color-coded region to another. The quantities are clustered in arrows with three different widths as shown in the legend (1, 5, 10 Exajoule)

Blog reader Panalion sent me a photo taken in Amsterdam’s Botanical Garden. It is of a map showing coffee and tea flows from producing countries to mainly Europe and North America. Panalion writes “I thought you might like this Sankey map I found attached to a cable between two palm trees. There were chairs set up to accomodate school classes”.

This map is for didactic purposes and features no absolute figures and no year. In addition to the export flows of coffee and tea shown as arrows the map also has circles of three different sizes representing percentage of world production of coffee, tea and cocoa in the originating country.

Infographers might have better ways of showing this information. But in this case I think it is sufficient to get the message across to the target audience, the school kids.

Actually not a Sankey diagram, but a map with Internet sea cable bandwidth. Eight differently coloured widths each of the “bands” representing max capacities in gigabits. No oriented arrows obviously as packages travel in both directions.


via whiteafrican

Original SVG file is creative commons, access here.

As promised in this post on U.S. 2010 Energy Flows here are some other Sankey diagrams from a July 2012 publication by Eric Shuster, NETL/DOE. These diagrams show world trade flows for coal.

The first one features the top coal exporters and their 2010 exports of coal to the regions America, Europe and Asia. This does not include domestic production, but just export. Indonesia and Australia are clearly the main exporters. Unit is in Mio short tons.

The other coal Sankey diagram is for U.S. coal imports and exports in 2010. Here the unit is in 1,000s of short tons, hence the two must not be directly compared. Also, the inset of the yellow arrow for domestic production in comparison to U.S. import/export is not to scale with the other flows shown on the flow map. In fact, all the blue Sankey arrows appear as a small export flow (81,716) in the yellow Sankey miniature, and all red flows on the world map are summarized as the tiny import flows (19,353).

The U.S. is primarily using its domestic coal and still able to export the surplus.

Stay tuned to see the world’s natural gas flows from the same publication

I am back after a few weeks of holiday. To get into posting again, here is a quick one I found at Graphic Design Forum in a discussion thread on software for creating trade flows (in this case oil flows) on a world map.

Flows in million tonnes (per year?). Scale element at the bottom left. No visible arrow direction, but instead a blue to green gradient on each band (blue for export, green for import). Middle East region being the largest exporter remains a problem with a very wide Sankey arrow leaving through the Indian Ocean.

John Cochran blogs about his coursework at University of Virgina. His project on ‘Urban Metabolisms’ has this Sankey diagram of food being transported to New York City. Data is from The Federal Highway Administration (USDOT) Freight Analysis Framework.

The first Sankey diagram shows transports to New York (excluding the Northeastern States and transports within NY). The food supplied by other US states becomes relatively insignificant:


The second one includes food transports within NY state (still excluding the Northeastern States):


John, however has not been satisified with the results of his work. He writes (scroll down to his September 21, 2011 notes):

“Neither produced effective graphics, but what they did demonstrate was the inability of the information to be able to represent food going to New York. (…) As a result, the data “revealed” that we already have a very local food system, when in reality this is not the case; instead, it does indicate how many extra miles are traveled for food around the location of purchase. (…) The images below demonstrate just how disproportionate the amount of miles traveled in New York are to the miles traveled bring food to New York from the rest of the country.”

It remains unclear whether the flows displayed in the diagram are for payload (e.g tonnes of food) or payload distance (e.g. tonne-kilometres). Also, it is not mentioned, whether, for example, water and drinks (typically sourced locally) are included.

I think the idea of thie Sankey map overlay is great, but the issue of spatial representation of (dense) data points has not been adequately adressed. A zoomed NY state would maybe help.