Point-and-Click Graph Tools - Graph Analysis and Visualization - page 249

button (or File ⇒ Import ⇒ Table ⇒ File), which enables you to import
the node file. Similar to the link file, you need to set the options,
delimiters, headings, and so on.
4. Note that Cytoscape does not like items that are empty or null. You are
better off putting in a zero or space for an otherwise empty item.
Visual Attributes
Cytoscape is powerful with regard to visual attributes. Just about any visual
attribute can be connected ( mapped ) to data. For example, beyond size
and color, Cytoscape offers node border color, node border width, node
transparency, label font, edge line type, edge transparency, edge visibility,
and so on.
You can access the visual attributes under the Style tab. The panel shows a
list of visual attributes organized by tabs at the bottom to switch between
node attributes and edge attributes. Note that additional visual attributes
may be available under the Properties drop-down. Each visual attribute has
three settings:
• Default —This button sets the default value for the attribute (for
example, set the edge color to black).
• Map —This button defines the mapping to translate data values into
visual attributes (for example, set the edge color based on passenger
volume data).
• Bypass —This button allows an override value for the attribute for the
currently selected subset of the graph. For example, all the links
associated with one node could be set to bright red. This is useful to
draw attention to part of the graph or otherwise mark specific nodes
and edges of interest.
While referring to Figure 7-21 , follow these steps to configure a visual
attribute:
1. First, in the Control Panel, under the Styles tab, find the attribute of
interest (for example, Edge Stroke Color) and expand it. This will show
additional rows to set the column to connect the attribute to and the
type of mapping to apply.