Bi-Directional Series Links

Well, the project is officially complete now - thanks to all who attended the presentation at the Archives, it was a lot of fun. In the next week or two I'll be retrospectively documenting the final stages of the project's development.

In a comment on the last post, Tim Sherratt observed that there seemed to be fewer links between Series than there should be. I did some digging in the data and discovered that links in the Archives' data are uni-directional. In other words, when Series A lists Series B as a related Series, Series B does not automatically reciprocate. The same is true for succession and control relationships: Series data lists subsequent Series links, but not preceding Series (which are subsequent Series relationships in reverse). Controlling links are listed, but not controlled by relationships.

In order to represent these links I first had to rewrite the parsing code so that when it finds a link, it simply records the link in two Series - at both ends of the link - rather than one. Thinking about directionality I decided that succession links all could be represented in the same way, regardless of direction: since the grid layout shows chronological ordering, that relationship is already clear (succession relationships are blue, above). Related Series could also be represented symmetrically - if Series A is related to Series B, surely B is also related to A (related links are yellow, above). Control relationships however are highly directional, so I introduced a new link type to represent the controlled by relationship. In the image above the controlled by links are purple, and lead from a large series to a number of smaller ones.

This tweak has a number of important results. Not surprisingly, the number of links increases - it doubles, in fact - providing more impetus to expore the context around a focused series. Also, the addition of the controlled by relationship makes small controlling Series far more findable because they are often linked from large Series, as in the image above.

You can download this latest (and for now final) version here for Mac, Windows or Linux (5Mb each, and requires 1280 x 1024). 

Update 20th August - updated these sketches to fix a memory allocation problem


Great work.

For the Linux version I had to add -Xmx512m (lower might work too) otherwise an OutOfMemoryError resulted on start-up (Ubuntu 9.04 JRE 1.6.0_16).

25 September 2009 at 12:44 pm  

Thanks Chris - funny I thought I had fixed that memory overallocation issue, I'll check the Linux builds...

25 September 2009 at 12:47 pm  

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