Understanding The "Edge Weight" Column

Sep 10, 2010 at 7:11 PM

I am a new user to NodeXL and am finding it to be a glorious thing! 

At the moment, I am using it to summarize the responses of 12 companies to a 30-question survey, and I am getting some really useful insights about how the companies break into groups.

However, I do have a clarifying question that I hope someone can help me with:

To help me learn how to use the model, I created a simple set of edges - A,B; A,C; A,D; B,C; B;D; and C,D.  I then refreshed the graph and got the expected nice "square" of the four vertices with the relevant lines.

Next, I copied the last edge pair, C,D, down 100 times. So now, of the 106 edges that I have, 101 of them are C,D. And sure enough (using the Fruchterman-Reingo algorithm) the refreshed graph shows the vertices C and D nicely huddled together, with A and B appropriately distant to the central pair.

Then I went to the ribbon, selected Automate, and used the "Merge Duplicate Edges" utility. As expected, this merged all the C,Ds into one line and added the new column "Edge Weight" with the count of 106.

Now, here's my question. When I then refreshed the graph, it then went back to the "square" shape, rather than showing C and D close together as I expected and wanted. I had expected that by merging the duplicates, I could still get the graph to reflect the fact that C,D has more connections and should be closer. In fact I was hoping that I could then change Edge Weight column to, say, increase the count and therefore drive the C and D vertices even closer together in the graph (or conversely lower the count to push them apart.) But when I tried this it did not work.

So I think I am misunderstanding something basic.  

I understand how I can filter out using various columns, but I want to know why when I merged the duplicates, the graph no longer recognized that that the C,D edge had the most number of incidences.  And is there any other column where I can in effect change the "number of times" an edge is repeated to directly change the graph layout.

Hope this makes sense (and is not too naive!)











Sep 11, 2010 at 6:51 PM


None of NodeXL's layouts take the Edge Weight column into consideration.  We have a work item to investigate that as a possible option, but at the moment the Edge Weight is ignored during the graph layout.  You can use Edge Weight to determine edge width, color, and opacity, but not the layout.

Sorry about that!

-- Tony

Sep 11, 2010 at 7:31 PM


Thanks and no problem - its a great product.

Well done.