About the Graph Template Language :: SAS(R) 9.3 ODS Graphics: Getting Started with Business and Statistical Graphics

For situations that require highly customized displays that are not available with the ODS Graphics procedures, you can write your own graph templates. You write templates using the Graph Template Language (GTL). A graph template is a program that specifies the layout and details of a graph. You can then apply the template to your data and render graphs using either the SGRENDER procedure or a DATA step.

The GTL is a powerful language that includes statements for specifying the following graphics items:

plot layouts, such as lattices and overlays
plot types, such as scatter plots and histograms
text elements, such as titles, footnotes, and insets

The GTL also provides support for built-in computations (such as histogram binning and loess smoothing) and the evaluation of expressions. The GTL supports dynamic variable assignment and conditional logic. Options are available for specifying colors, marker symbols, and other attributes of plot features.

In addition, the GTL has two features that enable you to customize a graph:

Draw statements enable you to draw visual elements anywhere within the graph. For example, you can add text, lines, shapes, and images to a graph.
Discrete and range attribute maps enable you to map visual attributes to input data values.

Procedure writers use the GTL to define graphs that procedures generate automatically in the process of an analysis. SAS analytical users can create very sophisticated graphs using terminology familiar to statisticians and analysts. However, with its robust capabilities and flexibility, the GTL requires an investment of time in order to learn how to best use it.

Here are two common uses for the GTL:

create highly customized displays by writing your own graph templates and applying them directly to data with the SGRENDER procedure.
modify the default SAS templates to make changes that are permanently in effect each time a particular procedure is executed. SAS provides a default template for every graph produced by statistical procedures.

The default graph templates provided by SAS are usually long and complex because they specify a complete description of how the graph is to be produced. You can edit graph templates to make simple modifications such as changing titles and axis labels or adding footnotes. Advanced users can make more substantive changes. This getting-started guide does not cover changes to the default graph templates.