Selecting Themes - TAMS, AWK and Manu Chao at half 3am

As part of my ongoing STS ethnography, I am trying to narrow down the theme which I a(i)m to analyse in depth.
For analysis, I use TAMS. It's friendly developer, Matthew Weinstein, supported me already several times by implementing some of my requests.
The figure shows a visualisation of how my themes emerge and how they relate. It is ultimately based on my construction of codes, and their association into code sets which TAMS is exporting to Graphviz. From there I converted it with a self-written awk-script into the graphml format, allowing to edit in other editors. I processed it with the centrality measure analysis of yEd and layouted it with the Spring Embedder algorithm of Visone.
I coded with AWK for about six hours, while listening to Manu Chao. ;)

Update 6th Feb: Yesterday, I enjoyed help by a user of a unix forum; now my awk-script automatically gets line breaks in the labels right.

If you like more information about this visualisation technique, let me know, e.g. via academia.edu or mendeley (see here for my profiles).