Graphics Reference
In-Depth Information
Figure 5-3:
E-mails between family members are shown here with nodes
accurately sized based on e-mail size. The smallest nodes are a few
kilobytes, and the largest are megabytes. The huge range makes teeny
nodes almost disappear and large nodes overwhelm.
If no scale or legend is visible, it is better to assume that sizes are relative
until you have a way to verify them.
Minimum Size, Overlap, and Other Options
Very small nodes may be difficult to see or even accidentally ignored. If your
data has some very small values, an alternative approach to relative size is
to set a
minimum size
.
When using a wide variety of node sizes, you can end up with items
overlapping or obscuring other nodes. As described in Chapter 4, “Stats and
Layout,” some layouts enable you to adjust node locations by node size (for
example, a no-overlap setting). Alternatively, you should ensure that small
nodes draw on top of large nodes or have large nodes be more transparent
than small nodes.
Another approach for nodes with a very large range of values is to use color
instead of size. Note that people are able to discriminate a wider range of
sizes than they are able to discriminate color, so typically it will be better to
use size.
Node Color
Color is a powerful visual indicator of data. Color has different attributes
such as
hue
(for example, red, yellow, orange, green), which is different
than
brightness
(for example, ranging from dark green to light green),
