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Re: Visualizations of trade structures
by Carl Nordlund
19 March 2002 02:45 UTC
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btw: the optimal distances between the actors (ie the forces that push and
pull the actors in the graph) are established through this formula:

distance=scaling/(sqrt(trading volume))

A short distance therefore implies high trading volumes and a long distance
implies low trading volumes. The data used covers all product groups (as I
understand it) between all pairs of countries in the data set.

> -----Ursprungligt meddelande-----
> Fran: Carl Nordlund [mailto:carl.nordlund@humecol.lu.se]
> Skickat: den 19 mars 2002 03:43
> Till: wsn@csf.colorado.edu
> Amne: Visualizations of trade structures
> Hello wsn list,
> I previously asked if anyone had any trade statistics available -
> I got many helpful replies, thanks for these! I am in great debt
> to professor Quee-Young Kim for the data I have used so far.
> I am currently experimenting a little on how trade statistics
> might be visualized graphically, in order to simplify the
> identification of possible structural exchange relations between
> economies. I have now imported the data for a set of countries
> for two periods - 1980 and 1995 - into a small computer program
> where I am using a spring-balance technique for balancing and
> positioning of actors in the network. It is written as a java
> applet and is run through an ordinary web browser - at this URL:
> http://www.demesta.com/carl/temp/graph/td80_95.html
> Use the buttons at the bottom to start, stop and restore the scenario.
> The crosshair in the middle is the average coordinate for the
> different actors and the circle is the average distance of the
> actors from this center.
> Toggling between the two time periods is done by clicking on the
> "change mode"-button. The scales are somewhat different between
> the two datasets - the trading volumes in 1995 were larger than
> the ones in 1980 so in order to make it easier to view I have
> scaled them to similar scales; similar, though not identical
> scales. Please note that it is possible to drag actors with the
> mouse - on some occasions (especially what regards actors close
> to the perimeter) there are a couple of possible positions for
> actors. (The tension variable should be as low as possible to get
> the best balance in the system)
> This is just an experiment on visualization and
> network-theoretical methods so I'm not very sure whether the
> graph is very informative or not; I am still a bit unsure on how
> to interpret the graph! However, I do think that the actors which
> establish positions at the center are usually regarded as core
> countries within the modern world-system and I also believe it is
> possible to identify clusters of regional trading partners.
> I would very much appreciate your comment on this, not only from
> the feasibility of the visualization at hand but also comments
> regarding what similar experiments have been done before and how
> the world(-)system(s) community look at quantitative methods in
> general as a complement to the more qualitative reasoning mostly
> found in traditional dependency/world-system analysis. Comments
> and feedback in general would also be most welcome.
> Yours,
> Carl
> - - -
> Carl nordlund, PhD student
> carl.nordlund@humecol.lu.se <mailto:carl.nordlund@humecol.lu.se>
> Human Ecology Division, Lund University, Sweden
> www.humecol.lu.se

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