Several years ago I experimented with spring-embedding algorithms and wrote a couple of java applet. I have also written a C# (Windows) client program to visualize the social network of the people attending my PhD graduation party, but that one was just an ordinary 2d-open type without calculating Kruskal stress indices.

I did an applet prototype that allows data to be displayed in a variety of spring-embedding ways - open 2d, open 3d, closed 2d (i.e. on the surface of a sphere) - and they work well for dense, weighted networks with many nodes. Also, the spring-embedders calculate Kruskal stress indices - although spring-embedders generally doesn't arrive at the optimum minimum for stress, you can tweak the parameters to minimize this value.

At that time, I primarily worked with international trade flow data which are also typically very dense and have huge value spans.

The program is located here:
http://demesta.com/sph_dev/test2/

If you could send me your data, preferably in a syntax like this:
http://www.demesta.com/sph_dev/test2/data/migflows.txt
...I can install it on the server so you can experiment with the applet to see whether it yields any good output.

Or a simple csv-textfile should also work - I can then convert into my format.

Yours,
Carl

Dr Carl Nordlund
carl.nordlund(at)hek.lu.se
Human Ecology Division, Lund university
www.hek.lu.se

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Från: Social Networks Discussion Forum [[log in to unmask]] för Andrei Boutyline [[log in to unmask]]
Skickat: den 17 maj 2011 05:49
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Ämne: [SOCNET] Plotting weighted networks in R or Python?

***** To join INSNA, visit http://www.insna.org ***** Dear all,

I'm hoping somebody can point me to a good tool for laying out and plotting weighted networks.  In my data, every node is connect to every other node, albeit with different tie strengths. So, a layout algorithm that doesn't take weights into account will just give me a ball of nodes.  Is there a library for R or Python that can produce a more meaningful layout from such data?  Or, in the absence of a library, is there a standalone program?

(By the way, the total number of nodes in my network under 150.)

Thanks a lot!
Andrei

--
Andrei Boutyline
University of California, Berkeley
PhD Student, Sociology
www.ocf.berkeley.edu/~andrei

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