Tag: Japan

Sankey Diagrams with matplotlib

The matplotlib.sankey module doesn’t get much attention, at least that is my impression when browsing the web for new Sankey diagrams. Maybe this is due to the fact that it primarily targets a tech audience, or at least people able to code in Python.

I have reported on this package back in 2011.

Here are two new examples from a Japanese blog.

And a top-down oriented Sankey diagram with arrows branching out to the right.

The project is on sourcefourge: API documentation, demos

Japan Material Flow 2003

Another wild like-to-be Sankey diagram. Found this on a resources and links list related to ‘material flow’ hosted at Hiroshima University.

The diagram is from a white paper on a ‘Recycling Society’ published 2006 by the Japanese Environment Ministry (HTML version). Data is for the year Heisei 15 (=2003), the book was published in 2006.

The title 平成15年度における我が国の循環資源フロー can be translated as ‘The resource flow cycle in Japan in 2003’ (any other suggestion from a native Japanese speaker out there?).

Flows are in million tons (百万t) per year as indicated in the top right. Values in square brackets relate to the previous year (2002). Flows are not to scale and their width seems to be chosen almost deliberately.

The diagram itself is a very interesting depiction of national material flows. Starting out from the 582 million tons of material (green box lower left), a large portion (220 million tons) is recycled, either directly as rejects from production (96 million tons) or after product use (124 million tons). 3 million tons are reused.

Still trying to figure out some more translations… three more thoughts:
(1) Could this general diagram setup serve as a role model to visualize reuse and recycling in a country. What are the common standards in national MFA accounts for this?
(2) Can I do this more nicely with a modern Sankey diagram software? Would be a nice challenge (mostly for the Kanji characters!)
(3) What would be the picture for Japan in 2015 in comparison to 2003?

Retrofit for a Maritime Vessel Engine

From what seems to be a 1998 abstract on retrofitting the main engine of the Japanese vessel Fukaemaru come these two Sankey diagrams. Found this on the website of the Kobe University Martime Faculty. Both nice plain black&white.

The first one shows energy efficiency of the original gas turbine equipped machine room. The base seems to be 100% energy (the label actually says ‘fuel exergy’) and the useful energy (arrow going straight up, labeled 出力) is 15.48% only. Losses branch out as arrows to the left and to the right.

The other Sankey diagram shows the energy flows for a diesel powered main engine. Efficiency is up to 37.38%

Read the full abstract here (in Japanese).

On a side note: funny to see that in the description of the figure at the bottom the author actually turned “Sankey Diagram” into a “Keysan Diagram”…

Exergy and Enthalpy Sankey Diagrams

Found the two Sankey diagrams on the website of the Exergy Design Joint Research Lab of Osaka University in Japan. The diagrams are for enthalpy and exergy in a Solid Oxide Fuel Cell (SOFC). Can’t fully understand what it means, but both are simple breakout Sankey diagrams that could also be presented as a pie chart.

The first one is titled “Enthalpy Sankey Diagram”:

The second one is a “Exergy Sankey Diagram”:

Anybody care to explain more?
Looking at the choice of color one could be led to believe that enthalpy is female, while exergy is male.

Energy Sankey Diagram for Japan

Some of you might have noticed that I tend to get somewhat excited when I discover Sankey diagrams in other languages.

Here is one I dug out on this webpage of the Tsuji Labs at Osaka University in Japan, and it has the honor to be the first one presented on this blog in Japanese!

The diagram shows the “energy flows” (エネルギーフロー) as relative values for the year 1993 only. On the left side we can see that more than 80% of the energy consumed in Japan were produced from imported fuels (輸入), while only 17.8% came from domestic production (国内生産). The quantities are broken down into the different types of fuels, such as crude oil (原油, 46,1%) , natural gas (天然ガス, 10,5%) or hard coal (石炭, 16,4%). The right side of the diagram shows the consumption sectors, with industry (31%), residential (16,9%) and transport (15,6%).

Losses are at 29% which seems relatively low, if you compare to similar Sankey diagrams from the U.S. But then I am not sure if they accounted for the losses in the same way for this diagram.

There are these two other similar Sankey diagram thumbnails on that site, and my guess is that they represent different energy scenarios, considering renewable energy sources, as an option to reduce dependency from imports. Maybe someone who can read and understand more Japanese than I do wants to comment?

Lying with Sankey diagrams (2)

The below Sankey diagram of the ‘Material Flows of Japan in the FY 2000’ has been published by the Japanese Ministry of Environment (環境大臣) and has been reproduced in a number of publications and presentations (sample PPT). Similar charts, representing the inputs into the Japanese economy and the outputs are available for subsequent years.

When I copied the values of the Sankey diagram and re-designed it (see pic 1 below), it quickly became obvious that the inputs (2130 Mio. tons) don’t match the Outputs (2386 Mio. tons). After some research I finally detected the reason for the mismatch in a footnote to the diagram in a press release by the ministry. It said that, “due to intake of moisture, etc., total output shall be larger than total material input.” This footnote might have been dropped unintentionally when using the diagram in other publications. I wouldn’t really call this “lying” (as the title of the post implies), but maybe negligence. I wonder if anyboy doubted the numbers when looking at the diagram?

In the second diagram below I adjusted this difference of 256 Mio. tons on the input side.


Another rather surprising thing in this Sankey diagram is the fact that the domestic food consumption within Japan (127 Mio. tons/year in 2000) was almost as high as the total quantity of material being exported (132 Mio. tons). Taking into account, for example, the number of cars being exported from Japan, and their weight, this sounds a little unlikely. However, I think that many of the produced goods might be hidden in the “Net Addition to Stock”.

And for the readers who study Japanese … Sankey diagram : サンキーダイアグラム