Exploring Data with Visualization Techniques : Animating an Image with a BY Variable
With
a BY variable assigned, you can animate an image in the Volume window. The values of a BY variable define groups of observations,
such as hour, month, or year. Specifying a BY variable lets you see how response
values change according to some grouping, like over time.
For example, if the specified BY variable is the hour
of the day and a point cloud is displayed showing the amount of sulphur in
the air at various coordinate locations, the point cloud reflects the amount
of sulphur for the locations at 9 o'clock, 10 o'clock, and so on.
To produce animation with a BY variable:
-
First,
you must specify a BY variable when you
load the data. For instructions, see Grouping Observations with a BY Variable.
-
Use a visualization technique to display an image,
such as a cutting plane, a point cloud, or an isosurface.
-
To automatically move through the BY variable
values, which animates the current image, select [Auto BY],
which is located at the bottom right of the interface. The values for the
BY variable appear at the left of the BY variable slider, changing as the
software moves through the values. (To stop the animation, click the left
mouse button.)
To manually move through the BY variable values, for
example, to see the image at a specific value, drag the BY variable slider,
which appears below the display windows, to the left of [Auto BY].
For example, using the EPA data set and specifying HOUR
as the BY variable, the following isosurface shows high sulfate concentrations
at hour 23.
Specified BY Variable
![[IMAGE]](./images/01213788.gif)
Copyright © 1999 by SAS Institute Inc., Cary, NC, USA. All rights reserved.
