SAS/SPECTRAVIEW Software User's Guide

Assigning Color to Missing Values

A missing value is a value in the SAS System indicating that no data is stored for the variable in the current observation. (Details about missing values in SAS/SPECTRAVIEW are explained in Understanding Missing Values.)

By default, missing values are transparent in an image; that is, the color assigned to missing values has RGB values set to zero. Changing the missing values to a color displays the data points in the grid without a response value.

To specify a color for missing values so that they can be displayed in an image:

Select [Palette].
Select [Missing]. Transparent Missing Values shows a point cloud with missing data points, due to the default transparent missing values.

Transparent Missing Values
Adjust the RGB sliders. As you move the sliders, the color appears in a square at the left, and the missing values display in the Volume window. You can also select a color chip, located below the RGB sliders. Colored Missing Values shows the point cloud now displaying the data points that are missing.

Colored Missing Values

Note that subsetting axes values with a WHERE clause when you load the data could cause otherwise valid data points to be discarded and regenerated as filler points, that is, missing.

Chapter Contents
Previous
Next
Top of Page