Had some trouble with the server that hosts the blog. There was some downtime, and I hope that you didn’t turn away from the blog annoyed… Back now!
New blog on MFA diagrams
A new blog dedicated to Material Flow Analysis (MFA) diagrams is available over at blogspot.
Material Flow Analysis (also refered to as Material Flow Accounting) is a research topic that focuses on specific substances or material flows on a macro level. Typically the system boundaries are a region or a country. Urban metabolism studies also use MFA diagrams. A key feature is the representation of stocks (storage or accumulation of material) within the system.
I have previously presented MFA diagram samples here on the blog that have Sankey diagram characteristics (i.e. arrow magnitudes proportional to flow quantities, directional arrows).
Here are two examples of MFA diagrams from the new blog for you to enjoy:
Platinum Flows in Europe. Source: Saurat, M., Bringezu, S., 2008. Platinum Group Metal Flows of Europe, Part 1 (via MFA diagram blog)
Phosphorus Flows. Source: Paul H. Brunner, 2007. MFA of regional lead flows and stocks [t/y] (via MFA diagram blog)
Make sure you visit the MFA diagram blog from time to time (I have put the link in the blogroll on the right), to see new interesting diagrams. I will also try to present some of them here…
Find the error…
Just back from a short break. A few nice Sankey diagrams and links to interesting diagrams in my inbox. To get into regular blogging mode again, here is one from my bookmark folder. Enjoy. More to come soon…
A simple percentage breakdown of mass inputs and outputs. Even though it only has 5 arrows (2 in, 3 out) there is an error in this Sankey diagram. Who can spot it? First commenter to tell the answer will get a honorable mention.
VisualizeGreen.com Free Sankey Template
Premnath Sundharam from the Visualize Green blog contacted me to draw attention to a Sankey diagram template he has made and that is available for download on his site.
The diagram is for predicted energy intensity for buildings. An Excel template is provided that allows entering the data. You can use this with the free trial version of e!Sankey (registering required). All elements of the diagram and the entry sheet is explained in detail by Premnath. In regard to the unit (KBtu per square foot per year) he says:
Last but not least, kBtu/sf/yr is becoming the universal (US) unit of communicating building energy consumption. This unit is called the EUI – Energy Use Intensity and since it is a simulation of how your building will perform, it is called PEUI – Predicted Energy Use Intenisty.
Good stuff, Premnath! Thanks for making this available to everyone.
Note November 2011: Also look at Premnath’s Energy Story here.
Misc Sankey Diagrams Uncommented 04
Found these two Sankey diagram on Wikiversity. I think it was somewhere on one of the sub-pages on the small solar vehicle… They show energy losses at the different components of the vehicle, such as at the solar panels or through rolling resistance. Percentage values.
These diagrams are made up from rectangles and simple arrows. Only straight arrows, no curves. The blue color of the border of some of the thinner arrows adds a strange effect…
Making Of an Infographic
A notice on scoop.it/visualdata led me to this fascinating video on visualnews. It shows the making of an infographic in two minutes or 3657 frames and is by Jess Bachmann for mint.com.
The central element of the infographic is a Sankey diagram on the trade flows between the United States and China (and to/from other countries).
it is interesting to see how Jess did every weighted arrow as a brush line with rounded head (the heads are neatly hidden behind the country maps, or capped at the other end). Each horizontal, vertical and curved segment is done individually.
In the YouTube comments of the long version of this video the author replied to one commenter: “After determining a metric, i.e 1 pixel width = $1M, I then stroked a line with the corresponding size brush. A $34M item would have a 34px width line. At one point you can even see a calculator popping up (0:55 into the video).
The long (7 minute) version has a lot more details on how the infographic comes to life. You can even see that Jess keeps saving his work from time to time…
Wow, what a hell lot of work – but the result sure looks gorgeous.
I calculated that Jess took more than 10h to complete this: 3657 frames, ten seconds between each frame = 36570 sec, 3600 seconds to an hour, makes 10.16 hours! I am just glad I have my Sankey diagramming software, so at least I don’t have to bother about brush sizes.
Sankey Diagrams in Python
I am impressed by the Sankey diagrams produced with ‘sankeypython’, a new open source project. I first came across this in a discussion forum, where Yannick Copin from France presented his work using matprotlib. The project is now at Sourceforge. This sourceforge link not working any more, check Matplotlib project instead (thanks to commenter Johannes for pointing out the broken link), and several Sankey Diagrams in Python samples can be seen there.
The most important functionality is available, such as labels for flows and units. Diagrams have a basic left-to-right orientation, with vertical arrows branching out on both sides. Color changes seem to be realized by combining several systems. There are apparently no node objects where the flows directly hook to (as is common in other tools), but by interlacing differently colored Sankey arrows a process step becomes kind of implicit.
This has only been up on Sourceforge since June 2011, so it will be interesting to follow further development on ‘Sankey Diagrams in Python’. I have added the project to the list of Sankey diagram software.
Engine Combined Cycle Power Plant Sankey
At the Technical University of Munich a project on Engine Combined Cycle (ECC) Power Plants aims at “improving the electrical efficiency of an engine combined cycle plant by using the exhaust gas heat in a steam cycle”.
The following Sankey diagram is shown to illustrate where heat can be recovered.
No absolute values are given, but the Sankey arrows represent the percentage of the primary energy. Four percent of the energy in the steam process can be recovered to add a total of 47.8% efficiency output of electrical power to grid. Losses branch out to the right side and are primarily via the cooling water and condensate at the steam process. The whole Sankey diagram is presented in a simple single-color design.