danryan.us

Q56.

• Go to NameGenWeb and select output in the form of a GraphML file. You may have to sign into to Facebook to make this work. When the program comes back and says "Thank you for waiting. Your network is now available" you can click and save or right click the link and save the file (to a directory where you will be doing your work). If you click the button you will see a .graphml.XML file that looks like this which you can Save as…:

<graphml xmlns="http://graphml.graphdrawing.org/xmlns" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://graphml.graphdrawing.org/xmlns http://graphml.graphdrawing.org/xmlns/1.0/graphml.xsd">
<key id="uid" for="node" attr.name="uid" attr.type="double"/>
<key id="sex" for="node" attr.name="sex" attr.type="string"/>
<key id="pic" for="node" attr.name="pic" attr.type="string"/>
<graph id="G" edgedefault="undirected">
<node id="name of a friend">
<data key="uid">219655</data>
<data key="sex">female</data>
<data key="pic">http://profile.ak.fbcdn.net/hprofile-ak-snc4/174207_219655_1563807427_s.jpg</data>
</node>
etc.

• If you right click you will save a .graphml file. Either file can be opened by NodeXL using File>Import GraphML file…
• In the Vertices worksheet, set the shape to 3 (disk). Double-click lower right corner of cell to auto-fill down.
• Use Graph Metrics to compute all metrics except In- and Out-degree.
• Use Autofill Columns to set vertex size to degree. Adjust sizes in Autofill Columns > Vertex Size Options as you like.
• Use Groups>Find Clusters (Girvan-Newman) to create groups of vertices.
• Under Layout Options (in Graph window at bottom of layout selection pull-down) select "Layout each of the graphs groups in its own box and …"
• For layout type try Harel-Koren¹
• Use Dynamic filters to drop "leaves" or "pendants" by setting degree to greater than or equal to 2
• To figure out what your clusters are, click on sample nodes. NodeXL will highlight rows in the vertices worksheet.
• Click on Graph Metrics>Average Overall Metrics. Look on the Overall Metrics worksheet to find
  • Number of connected components
  • Number of single vertex components
  • Maximum geodesic distance
  • Average geodesic distance (the "degrees of separation" in your ego network)
  • How many nodes does your network have? How many edges? What is the number of possible edges? What is the ratio of actual edges to possible edges? How does this compare to the graph density calculated by NodeXL?

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The program tells me I have 32 total connected components, of which 26 are single vertices. Thus, 26/343 or about 7.5% of my Facebook friends are singletons — not friends with any of my other friends. And then the rest of my friends are divided among 6 connected components.

The "giant component" contains 300 of my 343 friends. The other five connected components are five friends from my graduate dorm, two students from the class of ~2004 (one who is Czech and one who studied there), two folks I who worked in New Haven city government when I lived there, a married couple who also lived in the graduate dorm, and my two college physics teachers. These last three do not show up on the visualization because I set the visibility threshold to degree 2 and above and the members of these dyads each have degree 1.

My 343 friends could have a maximum of $\frac {343 \times (343-1)} {2} = 58,653$ edges. In fact they have 1,578. Therefore, the density of the network is $\frac {1,578} {58,653} = 0.0269$.

The maximum "degrees of separation" among my connected friends is 10 and the average distance between any two friends (not including me - that would always be 2) is 3.6.

See Also

[http://grupsderecerca.uab.cat/egolab/sites/grupsderecerca.uab.cat.egolab/files/Beagephi.pdf]