Graphics Reference
In-Depth Information
Figure 4-10:
In this force-directed layout of patent citations, any
indication of which nodes came earlier and which nodes came later is not
visible.
This is a perfect example of where a force-directed layout is ineffective.
The time element is an essential feature in understanding this data. To
better understand which items came first and which items came later, a
layout is needed where the sequence is preserved. A hierarchical layout, or
a
directed acyclic graph (DAG)
layout, will preserve order so that the
direction is always pointing down (or right).
The layout in
Figure 4-11
is the same patent data (using the hierarchical
layout from Cytoscape) with the earliest patents at the top and later patents
toward the bottom. Although the layout isn't as compact as the previous
