Edge Weights and Betweenness

Jun 13, 2011 at 9:52 PM

I have a couple of questions concerning NodeXL. I am just starting to use it, and am hoping to use it in my research project involving road networks. First, is there any way to input a measured weight for an edge into NodeXL?

And second, does betweenness take weights and directionality into account or does it consider the graph to be undirected and unweighted?

Thank you very much.

Jun 13, 2011 at 10:08 PM

NodeXL's use of edge weights is limited.  Specifically:

1. If you tell NodeXL to merge duplicate edges (NodeXL, Data, Prepare Data, Merge Duplicate Edges), it will add an Edge Weight column to the Edges worksheet and populate the column.

2. You can add an Edge Weight column to the Edges worksheet yourself, and populate it manually with whatever data is appropriate for your edges.

3.  If you import your graph data from a GraphML file, which is an industry-standard graph data format (NodeXL, Data, Import, From GraphML File), and the GraphML includes edge weights, those edge weights will get imported into the Edges worksheet.

4. In any case, you can use the Edge Weight column to automatically set the edge colors, widths, and opacities.  See NodeXL, Visual Properties, Autofill Columns.

NodeXL does not take edge weight into account when calculating betweenness centrality (NodeXL, Analysis, Graph Metrics).  It does take directionality into account when calculating betweenness centrality.

-- Tony