Database Reference
In-Depth Information
The two lines in Figure 2-2 are, in fact, the same length. Of course, you are
unlikely to end up with such an extreme example in your visualization, but
the use of a gradient background or a watermark could lead to more subtle,
but just as misleading, misinterpretation. Using grid lines, as in Figure 2-3, aids
the viewers' comprehension.
FIguRe 2-2
Which line is
longer? The one on the bottom,
or the one on the top?
FIguRe 2-3
Using grid
lines to aid perception
Another key to human perception is choosing an unambiguous dimension
upon which you show values. On the left in Figure 2-4, it is immediately appar-
ent that we are measuring the difference in height. In the middle pair and on
the right, it is immediately apparent that we are using angle. But which of these
changes in the angles is equivalent to the left-hand change in the height?
FIguRe 2-4
Changes in angles versus changes
in height
