Category Archives: network viz

Stasi SNA

ProPublica published an interesting example of a hand-drawn sociogram / mind-map of the relationships of a person of interested to the former East German secret police.

The graphic shows forty-six connections, linking a target to various people (an “aunt,” “Operational Case Jentzsch,” presumably Bernd Jentzsch, an East German poet who defected to the West in 1976), places (“church”), and meetings (“by post, by phone, meeting in Hungary”).

The article links to a version of the document that provides english translations on mouseover.

Reminds me of similar diagrams I’ve seen in police files related to Black Panther activists.

Multiple modes of flying flows

While trawling for interesting dynamic network datasets, I bumped into one about U.S. airport passenger traffic aggregated by Zachary Neal.. I lifted this image from his slides (p.9):
airportTransitNets

These data contain annual U.S. air traffic flow networks from 1993 to 2011. They were constructed from Bureau of Transportation Statistics’ Origin and Destination Surveys using the AIRNET program

What I thought was cool is that he constructs the network in two ways: one is the passenger flow between specific airports, the other is total passenger movement between metropolitan areas (if I’m reading his data correctly). He claims the first approach yields a hub-spoke network driven by airline hubs, while the second highlights travel between dense population areas. Both are derived from the same data. I think it shows how important it is to think carefully about how to construct networks that correspond well to the phenomena being studied. Are we interested in relative traffic between cities, or in the the actual flow of people (via roads, airports) between the cities? In hindsight, its obvious that these are very different networks (the first one for example should be nearly fully connected, right?).

I’m assuming that there is some thresholding going on in these images, ’cause the dataset he provides seems to have lots more edges in it.

Relationship Timelines

I finally had a chance to pull together a bunch of interesting timeline examples–mostly about the U.S. Congress. Although several of these are about networks, the primary features being visualized are changes in group structure and membership over time. Should these be called “alluvial diagrams”, “stream graphs” “Sankey charts”, “phase diagrams”, “cluster timelines”?

James Moody and Peter Mucha’s Portriat of Political Party Polarization (in the new Network Science journal) plots the network modularity score of structurally-equivalent voting clusters in the Senate co-voting network as they change over time. The lines show the movement of Senators between clusters over time.
moodyCongressPolarization

The figure maps this dynamic coalition network, one two-year Congress at a time. Nodes indicate structurally equivalent positions, scaled by number of Senators and shaded by their voter agreement level. In each period there are two “party loyalist” positions, anchored on the y-axis proportional to the modularity score. The y-position of other nodes—usually individuals—is based on the balance of their votes relative to these anchors. Positions are linked over time by identity arcs connecting each person to themselves over time, labeled to trace individual careers (the widths of arcs between aggregate positions indicate the number of people moving between them over time).

Continue reading Relationship Timelines

ndtv animation “live” at London Science Musuem

Dr. Michael White wrote to let me know about an exhibit / performance at a science museum that used a network animation produced with the ndtv package.

… we used QR codes and tablets to monitor the spread of an infectious disease throughout people attending the museum, and perform dynamic network visualizations in real time.

The article is a little vague about exactly how this worked, but it sounds like the visitors were given tokens to pass to each other, a few of which were labeled “infected”, and at various points they were scanned in by staff and the data used to update the animation of the transmission network? The animation is included in the article. Cool to see the software used in real life!

The Other Kind of Network Marketing

Private Equity firms and shady deals from Darwin BondGraham

Oakland political economy journalist/blogger Darwin BondGraham has an interesting article about a court case that appears to reveal massive collusion between private equity firms to manipulate markets and cheat investors when doing leveraged buyouts (I think thats what “LBO” stands for?) of public companies. Darwin includes some network diagrams, apparently bi-partite networks of the major firms and their shady deals extracted from Dahl v. Bain court documents unsealed by the NYT. The document is a surprisingly riveting read, kind of like techno-thriller-horror script.

50 nets of Grey

Just saw this really nice blog post at badhession.org explaining how to do Exponential Random Graph Modeling (ERGM) using a sexual-hookup network from the TV show Grey’s Anatomy.

Grey's Anatomy sexual-hookup network image

I do some work on some of the dynamics packages in statnet (‘tho not the amazing stats part demoed in the post) so its great to have something to point to explain what the project can do. Now we just need to go back and add the timing information to the edges (who was partnered in which episodes) to be able to estimate the number of concurrent partnerships and look at the epidemic-spreading potential of the network…
(via Brian Keegan)