Basic Analysis and Graphing - SAS

Chapter 13 Creating Three-Dimensional Scatterplots 363
Scatterplot 3D Platform Options
Figure 13.6 The Density Contour Controls Window
first contour level
second contour level
third contour level
Table 13.5 Description of the Density Contour Controls Window
Contour Quantile
Controls which contours are shown and lets you customize the contour
formatting.
• Density level represents the volume and density of the points. As the
contours go from smaller to larger values, the contours cover less volume
but more dense areas. A 0.9 contour represents the 10% densest part of
the total, where the points are closest together. Click and drag the slider
below “Contour Quantile,” or enter a value next to the slider.
• Transparency changes the surface of density contours. The greater the
value, the more opaque the contour. Enter a value in the box.
• Color changes the color of the contour. Click the colored box and select a
different color. (This option only appears for ungrouped density
contours.)
Changes to these settings take effect immediately.
Resolution
Column Bandwidth
Changes the resolution of the contours. A higher resolution results in a less
granular drawing of the contours but takes more time to display.
Changes the smoothness of the fitted density. A higher bandwidth results in
a smoother fitted density.
Type a new bandwidth for each variable, or click and drag the sliders. Click
Apply to display your changes.
Optimizing a Dense Nonparametric Density Contour
When you have many points on a 3D scatterplot, the contours can be so dark that you cannot see the
structure. In this situation, you remove the points so that only the contours are displayed.