Blog reader Johannes send me a note and suggested to feature the below diagram. Thanks for that.

Tony Hirst from created it after seeing a map-based diagram for horse meat trade flows on the Guardian Data Blog. Tony used Mike Bostock’s D3s Sankey Plugin that allows creating this type of diagrams directly from data in Excel/CSV files. In his post he describes how he proceeded to build this Intra EU Horse Meat Trade diagram. Somewhat techie, but nevertheless makes an interesting read.

Overall trade quantity was more than 60.000 tonnes in 2012. Largest exporters are Belgium and Poland (left side), largest importers are Italy and France (right side). Data is from Eurostats.

The above is a only a static picture, but you can go here to play around with the interactive version. Data labels and quantities are available in the interactive version when you hover ths mouse over certain bands. You can also move the nodes up and down vertically and group the countries differently.

This special type of Sankey diagram is also refered to as distribution diagram and (…hate to say it in light of the current scandal) a Spaghetti diagram. Fineo and Parsets (see software list) can also be used for this type of diagrams where statistical data is grouped into categories (here: exporting and importing countries) and bands/streams/spaghettis are shown between the categories to represent the relationships between them.

Here is my May 2012 post on distribution diagrams with d3.js.

Browsing through the blogs on data visualization and infographics (check my blogroll) I often find inspiration in Nels’ MFA diagrams. From time to time I like to beef up the skinny MFA diagram skeletons a bit by converting them into Sankey diagrams. At the same time, by translating the numbers into Sankey arrows one gets a better idea what the main (mass) flows are.

This is a MFA diagram on Iron and Steel Flows in the European Union in 2000 as found in this post. Original data is from a 2008 OECD study, flows in Mt.

The description of the diagram says: “A study of iron and steel flows in 2000 in the European Union showed that an input of about 120 Mt of iron ore (of which 98 Mt was imported) yielded 98 Mt of primary crude steel (i.e. produced directly from iron ore and coke). A further 65 Mt, representing 40% of total crude steel production, were produced as secondary crude steel, produced from scrap steel.”

I did a first quick version of the flows as Sankey diagram, trying to stick very much to the layout of the original diagram. All nodes are the same size and more or less located at the position of the master. It already shows that the main steel flows: iron ore imported into the European Union, and steel scrap being recycled within the EU. Export of semi-finished steel products from the EU to the Rest of World (52 Mt) almost balanced with 47 Mt of semi-finished steel products imported into the EU.

I tried to improve the diagram by removing the three nodes ‘New Scrap’, ‘Prompt Scrap’ and ‘End of Life products’ since there is no transformation of these flows at the nodes (also no change in quantity). Further I reduced the size of some boxes and dragged the ‘Semi-finished Products’ (Rest of World) box closer to the ‘Finished Steel Products’ (European Union) box to avoid crossing streams. Wherever possible I try to avoid diagonal arrows.

The final result also has the Rest of World and European Union grouping. I am not to happy with the colors though.

Your thoughts?

Finally have I run across a European Energy Flow Sankey diagram in a post on Google Groups…

European (EU-27) Energy Usage:

European (EU-27) Energy Usage (renewable energy sources only):

These two images were posted by Herman B. (apparently linked somehow to the European Comission) in reply to an inquiry by Andrew D. I don’t know the original source or publication. Flows are in petajoule (PJ) for the year 2006.

In my optinion they could do without the background image and the photos, but nevertheless, these are fine Sankey diagram examples.