Databases Reference
In-Depth Information
The color encoding from low value to high value is used to enhance the
preattentive effect. It can, however, distort the value assessments. For example,
the pale yellow encoding for Utah does not mean that the median age there is
close to zero; it just means that it is the lowest value. To avoid such a distortion
you can specify that the low value for color encoding is zero.
Check the “Zero Based” radio button in the “Color Encoding” box to make
the change.
Now Utah doesn't look quite so young. When viewing the data it is a good
idea to do the color encoding both ways. Each has its advantages. Of course,
since VisMiner supports multiple displays and view partitions within each
display, you could open two boundary viewers for the same data. Use one for
“Range Based” encoding and the other for “Zero Based”.
Zoom in again by rubber banding the northeast states. Include from
Virginia on the south and Ohio on the west. See Figure 2.31.
Check the “Range Based” color encoding and answer the question, “Which
northeastern state has the lowest median age?” After a careful comparison
you should answer Virginia.
Check the “Relative to Visible” radio button also found inside the color
encoding box. Is it now easier to locate the youngest and the oldest states?
Figure 2.31
Northeast States - Median Age
