Attractive and well designed network visualization layouts are complex to automate. Many researchers have devoted a great deal of effort to refining algorithms that assign the best set of positions to a set of nodes. In many cases a layout algorithm will work well for some types of graphs and not others. NodeXL has a few network visualization layout algorithms to choose from (Harel-Koren and Fruchterman-Reingold) and we plan to add one or two more in the coming months based on leading new approaches to automated layout.
Today, we release a new NodeXL feature in version .164 that we think will improve the results generated by other layout algorithms: Group Layout. In the Layout Options menu in the NodeXL Network Graph Pane (called “Document Actions” by Excel) you will find that the dialog box has been updated:
Selecting the new “Lay out each of the graph’s groups in its own box and sort the boxes by group size” option and checking the “Show each box’s outline” can generate an image that neatly places each group in a bounded region.
Here we see the set of connections among the people who tweeted the string “msrtf11 OR techfest” – referring to the Microsoft Research TechFest 2011 event that took place in early March in Redmond, Washington. This map clarifies the set of set of relationships among sub-groups within the graph.
Contrast this with the layout created without this feature turned on:
We still have some refinements coming that will improve this layout further (for example, the neat grid of isolated nodes takes an extra step today, we will try to make that happen automatically soon) but this is a nice step in making network graphs easier to understand. Let us know what you think!