Graphics Reference
In-Depth Information
technique, small worlds are organized into larger bounding group nodes,
and, while their internal links are visually preserved, links to nodes outside
the world are instead aggregated and drawn between groups, as shown in
Figure 13-5:
Grouping small worlds and aggregating links between them
is another useful technique for being able to see flow clearly.
In the transport data set used for this exercise, every state is connected
to almost every other state. The whole country is a small world, making it
unsuitable for this technique.
Link Rose Summaries
Links are the essence of a spatial network visualization. But when nodes
are highly connected, and the center of the network is densely populated,
drawing lines between each of the nodes creates visual interference.
Looking again at the Gephi interstate transport visualization in
Figure 13-4
,
restrained use of color and opacity has revealed a few broad-stroke
characteristics of large states like Florida, California, and New Jersey, but
it is difficult to see much else. What are the characteristics of transport
to and from Montana? How do Massachusetts and Virginia compare? You
can see approximately where major transport corridors must lie, but this is
somewhat misleading because the data does not contain route information.
Are there any other interesting patterns that can be observed?
