Overview
Do you need to display and analyze a network graph but you don’t want to deal with difficult applications, arcane file formats, or advanced programming languages? NodeXL may be what you’re looking for.
NodeXL is a template for Excel 2007 that lets you enter a network edge list, click a button, and see the network graph, all in the Excel window. You can easily customize the graph’s appearance; zoom, scale and pan the graph; dynamically filter vertices and edges; alter the graph’s layout; find clusters of related vertices; and calculate a set of graph metrics. Networks can be imported from and exported to a variety of data formats, and built-in connections for getting networks from Twitter, Flickr, and your local email are provided.
If you are new to network graphs, you can find a network graph overview
here.
The NodeXL Template in Action
This is what the NodeXL template looks like. In this example, a simple two-column edge list was entered into the Edges worksheet, and the Show Graph button was clicked to display the network graph in the graph pane on the right.
The two-column edge list is all that’s required, but you can extensively customize the graph’s appearance by filling in a variety of optional edge and vertex columns. Here is the same graph after color, shape, size, image, opacity, and other columns were filled in.
Some NodeXL Features
Importing Data
NodeXL can import graph data from a variety of file formats, including GraphML, UCINet, Pajek, and matrix. It can also connect directly to the Twitter and Flickr Web sites, letting you import the network of people who have recently tweeted a certain term, for example, or a network of related Flickr tags. If you use Outlook, Windows Mail, Outlook Express, or a similar email program, NodeXL can import a network from your email – the network of all the people you communicated with last week, for example.
Autofilling Columns
Although you can manually fill in the optional edge and vertex columns that control the graph’s appearance, you can also have NodeXL fill in the columns automatically based on other data columns that you specify. For example, you can easily set the size of the graph’s vertices based on vertex degree, or the opacity of the edges based on edge weight.
Laying Out Graphs
NodeXL will lay out your graph using either a “force-directed” layout (Fruchterman-Reingold or Harel-Koren fast multiscale) or a geometrical layout (circle, grid, spiral, etc.).
Zooming, Panning and Scaling
You can use the mouse to zoom into the graph to examine areas of interest. The vertices and edges can be scaled to improve the legibility of particularly dense graphs.
Dynamic Filtering
A set of slider controls let you filter the graph on the workbook's numeric and date/time columns. For example, you can instantly hide all vertices with degree less than three, or all edges that have associated dates earlier than January 1, 2009.
Calculating Graph Metrics
NodeXL will calculate degree, betweenness centrality, closeness centrality, eigenvector centrality, clustering coefficient, and graph density. Additional graph metrics are planned for a future release.
Creating Clusters
A graph's vertices can be automatically or manually grouped into clusters that are distinguished by color and shape.
NodeXL Graph Gallery
Here are some graphs that were created with NodeXL.
 |  |
| John Crowley | Cody Dunne |
 |  |
| Marc Smith | Pierre de Vries |
 |  |
| Eduarda Mendes Rodrigues | Tony Capone |
 |  |
| Tony Capone | Eduarda Mendes Rodrigues |
NodeXL Documentation
See the NodeXL
one-page flyer.
A draft slide deck providing an overview of NodeXL is available
here.
The
NodeXL Tutorial, by Derek Hansen, Ben Shneiderman, and Marc Smith, introduces some of the core functionality of NodeXL using a few simple datasets. The current draft of the tutorial is based on NodeXL version 1.0.1.88 and was uploaded on June 22, 2009. The tutorial will serve as a basis for the Communities and Technologies 2009 Workshop. It takes approximately 4 hours to go over in a classroom setting with students following along on their own machines. The tutorial relies on the following datasets, which are NodeXL files:
If you plan to use this tutorial in a classroom setting, please contact Derek Hansen (dlhansen@umd.edu). Derek is keeping track of the courses where NodeXL is being used. Feedback is welcome.
You might also be interested in the following:
NodeXL PublicationsNodeXL Data Analysis Task ListNodeXL Links
NodeXL for Programmers
The NodeXL template displays graphs using a custom Windows Presentation Foundation (WPF) control that can be reused in other applications. In fact, the template is just an application wrapper around a set of reusable, prebuilt class libraries. Check the
Downloads tab for the latest version of the class libraries.
You can create a .NET assembly that will import graph data from a custom source into the NodeXL template. These "plug-ins" appear in NodeXL's Data, Import menu. See
For Programmers: About NodeXL Plug-Ins for details.
NodeXL is Brought to You By...
NodeXL was created by Marc Smith's team while he was at Microsoft Research. Smith is now at the
Connected Action Consulting Group.
Contributors to NodeXL include:
- Natasa Milic-Frayling (Microsoft Research Cambridge)
- Marc Smith (Connected Action Consulting Group)
- Ben Shneiderman (University of Maryland)
- Cody Dunne (University of Maryland)
- Tony Capone (Microsoft Research Redmond)
- Eduarda Mendes Rodrigues (University of Porto)
- Udayan Khourana (University of Maryland)
- Annika Hupfeld (Microsoft Research Cambridge)
- Jure Leskovec (Stanford University)
Friends of NodeXL include:
- Dan Fay (Microsoft Research Redmond)
- Vladimir Barash (Cornell University)
- Eric Gleave (formerly at University of Washington, now at Booz Allen Hamilton)
- Adam Perer (formerly at University of Maryland, now at IBM Research)