Visualizing Proportions - Data Points: Visualization That Means Something - page 149

Here are the numbers in table form.

Issue ApproVe DIsApproVe no opInIon

Race relations 52 38 10

Education 49 40 11

Terrorism 48 45 7

Energy policy 47 42 11

Foreign affairs 44 48 8

Environment 43 51 6

Situation in Iraq 41 53 6

Taxes 41 54 5

Healthcare policy 40 57 3

Economy 38 59 3

Situation in Afghanistan 36 57 7

Federal budget deficit 31 64 5

Immigration 29 62 9

One option would be to make a pie chart for every issue, as shown in Fig-
ure 5-12. To do this in Illustrator, all you have to do is enter multiple rows of
data instead of just a single one. One pie chart is generated for each row.

However, a stacked bar chart enables you to compare approval ratings for
the issues more easily because it's easier to judge bar length than wedge
angles, so try that. In the previous chapter, you made a stacked bar chart
in Illustrator using the Stacked Graph tool. This time you add some simple
interactions.

CrEATE AN INTErACTIVE STACkED bAr ChArT
Like in the donut chart example, use Protovis to create an interactive
stacked bar chart. Figure 5-13 shows the final graphic. There are two
basic interactions to implement. The first shows the percentage value
of any given stack when you place the mouse pointer over it. The second
highlights bars in the approve, disapprove, and no opinion categories
based on where you put your mouse.