This feature is particularly valuable 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. See Optimizing a Dense Nonparametric Density Contour for details.
You display and remove nonparametric density contours by selecting and deselecting Nonpar Density Contours from the red triangle menu.
Figure 5.5 The Density Contour Controls Window
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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.
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Transparency changes the surface of density contours. The greater the value, the more opaque the contour. Enter a value in the box.
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Color changes the color of the contour. Click the colored box and select a different color. (This option only appears for ungrouped density contours.)
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Type a new bandwidth for each variable, or click and drag the sliders. Click Apply to display your changes.
To remove points from a 3D scatterplot, select Show Points from the red triangle menu. You can further optimize the contours by changing their size, color, and transparency. See Scatterplot 3D Platform Options for details.
