Layouts

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Last week’s NodeXL meeting focused on the coming work items for the next release.  Four major items are lined up for the next few weeks.  We may publish a release once a few of these items are complete.

> Legends and axes with scale marks for the chart canvass.

This is part of our larger work item called “Make the charts ready to publish”.  A related work item to address this goal is export to a vector file format.  A scalable vector format will allow people to create graphs of arbitrary resolutions to fit their presentation needs.

> Export to XPS (which should make it possible to get our files to PDF with some 3rd party help!)

Since NodeXL is intended to support non-programmer network analysts we plan to add support for other network analysis file formats.  A leading example is the UCINet format which has the added virtue of holding many sample data sets that are widely used in classes and network course work.  If you have a network data file format you would like NodeXL to support feel free to comment here or on the Codeplex NodeXL discussion.

> UCINet file format compatibility

Improvements to the layout of complex graphs is a deep area of research.  A recent member of the NodeXL team, Janez Brank has proposed and prototyped an alternative mechanism for node layout, namely the Fast Multi-Scale Method from Harel and Koren. This method initially selects a small subset of nodes and lays them out; this initial layout is then refined in several iterations, with more and more nodes added to the layout in each iteration, until a layout of the entire graph is created. The cost function used to optimize the layout at each step is designed to reward layouts in which the Euclidean distance between nodes corresponds approximately to the length of the shortest path between them. Our developer, Tony Capone, plans to implement the design in the coming weeks.  We have not added a new layout for a while and those recent additions have been deterministic geometric layouts like grid, circle, and sine wave.  We have never added an alternative to the Fruchterman-Reingold force directed layout with which we started the project.  This is a big feature addition that should have a big impact in making NodeXL layouts more visually appealing and informative.

> Updated layout #1

We hope these features deliver a lot of value to our users and address the big themes the team is working towards: Scale, Clarity, and Connection.  We seek to make NodeXL perform against reasonably sized data sets, to improve the exploration and discovery of structures in graphs, and to simplify the import and export of data between NodeXL and social media network data sources beyond the email and Twitter support present in the application today.

Some other features that we have been considering include: