Network graphs have become a popular visualization in the past couple of years in not only the Mathematics and Computer Science, but in different fields such as the Humanities and Politics. It is one thing to read a piece of text and to be introduced to different characters and their relationship to each other in a novel, but it’s quite another thing to visually see the connects each character has with each other. These visual relationships can draw new conclusions or points of interest for research that were never discovered or approached before. This is in part why network graphs have gained popularity in the recent years.
In the Digital Humanities, network graphs are popular with sociologist to study social networks using these visualizations. The topic of bibliometrics, the study of patterns and relationships in the formal record of scholarly communication, has been given a refreshed look using visualizations via network graphs to help Humanists study the structure of academic disciplines through connections among scholars. There are a few tools out there that take the data and produce the network graph, but the ones that always stand out in this field for the Digital Humanities are Gephi (which has a big learning curve if you are starting from square one) and NodeXL (which uses Microsoft Excel to create a network graph).
I recently downloaded the NodeXL template to see how it worked. According to their site NodeXL is ” a free, open-source template for Microsoft® Excel® 2007 and 2010 that makes it easy to explore network graphs. With NodeXL, you can enter a network edge list in a worksheet, click a button and see your graph, all in the familiar environment of the Excel window.” The advantage of using NodeXL over Gephi is, if you are very familiar with Excel, you might prefer this tool to create network graphs.
In the NodeXL template, there is a tab for the NodeXL tool. This is where you can import data (Pajek and GraphML files, and even Twitter, Filckr, and YouTube Networks) to create you network graph. You can control the color, size, and shape of the vertex and edges. The spreadsheet makes it easy to edit your network data and the convenience of having the visualization appear to the right of the spreadsheet (which you can manually update as you add or change data) makes it a useful tool. You are able to export the visualization and data into a number of files including a Pajek file, UCINET Full Matrix DL file, GEXF file, and GraphML file.
To download NodeXL, click here: http://nodexl.codeplex.com/
To see how other another Humanist (Lisa Marie Rhody) is using this tool in her latest project, Revising Ekphrasis, which uses advanced computational tools to explore connections between 4,500 English-language poems, click here: http://www.lisarhody.com/
The group that developed this tool is listed here: http://nodexl.codeplex.com/team/view