Modeling and Multivariate Methods - SAS

Chapter 23 Plotting Surfaces 537
Surface Plots
Surface Plots
The Surface Plot platform is used to plot points and surfaces in three dimensions.
Surface plots are available as a separate platform (Graph > Surface Plot) and as options in many reports
(known as the Surface Profiler). Its functionality is similar wherever it appears.
The plots can be of points or surfaces. When the surface plot is used as a separate platform (that is, not as a
profiler), the points are linked to the data table—they are clickable, respond to the brush tool, and reflect
the colors and markers assigned in the data table. Surfaces can be defined by a mathematical equation, or
through a set of points defining a polygonal surface. These surfaces can be displayed smoothly or as a mesh,
with or without contour lines. Labels, axes, and lighting are fully customizable.
Launching the Platform
To launch the platform, select Surface Plot from the Graph menu. If there is a data table open, this displays
the dialog in Figure 23.2. If you do not want to use a data table for drawing surfaces plots, click OK without
specifying columns. If there is no data table open, you are presented with the default surface plot shown in
Figure 23.3.
Figure 23.2 Surface Plot Launch Dialog
Specify the columns you want to plot by putting them in the Columns role. Only numeric variables can be
assigned to the Columns role. Variables in the By role produce a separate surface plot for each level of the
By variable.
When selected, the Scale response axes independently option gives a separate scale to each response on
the plot. When not selected, the axis scale for all responses is the same as the scale for the first item entered
in the Columns role.