When a particular node in a network is of special interest it can be useful to create a network visualization in which it is located at the center of concentric rings of vertices.
NodeXL supports a “Polar” layout in which each vertex has two values that govern its location: distance from center (“Vertex Polar R”) and the angle around the clock (“Vertex Polar Angle”).
Using a random network, we added two columns to the Vertices worksheet that we called: Ring (or “Vertex Polar R”) and Rotation (or “Vertex Polar Angle”). We then assigned values for the “Ring” and the “Rotation” for each Vertex:
These values can then be mapped to the location for each Vertex using the NodeXL Autofill columns feature:
When these values are applied to the network visualization and the layout is set to “Polar” the visualization repositions each vertex into a position around a ring. The values are set by mapping Vertex Polar R to “Ring” and Vertex Polar Angle to “Rotation” and then selecting “Autofill”. The result is a single ring plotted around a core:
To see this more clearly, I built a larger random network with 100 vertices and added two more “rings”. The resulting image looks like this: