This chapter discusses the graph template language and graph template modification in ODS Graphics. Be sure that you are familiar with Chapter 21: Statistical Graphics Using ODS, before reading this chapter.

Graph templates control the layout and details of graphs produced with ODS Graphics. The SAS System provides a template for every graph produced by statistical procedures. Graph template definitions are written in the Graph Template Language (GTL). This powerful language includes statements for specifying plot layouts (such as lattices or overlays), plot types (such as scatter plots and histograms), and text elements (such as titles, footnotes, and insets). It also provides support for built-in computations (such as histogram binning) and the evaluation of expressions. Options are available for specifying colors, marker symbols, and other attributes of plot features.

Graphs, like all SAS output, are constructed from two underlying components, a data component (or data object) and a template. Procedures supply a table of data values and statistical results to plot. Together, the data object and the template form an output object that ODS displays in one or more output destinations. You can control this display in two ways. You can use the ODS Graphics Editor (discussed in the section ODS Graphics Editor in Chapter 21: Statistical Graphics Using ODS,) to modify the output object (but not the underlying data object or template), and you can use the GTL to modify the template. With just a little knowledge of the GTL, you can modify or edit templates, even when you do not understand most of the syntax used in the template definition. See examples starting with Example 22.1.

Note: You do not need to know anything about the GTL to create statistical graphics.

This section provides an overview of the Graph Template Language. It also describes how to locate, display, edit, and save templates. A template definition is a set of SAS statements that is used together with PROC TEMPLATE to create a compiled template. In addition to graph templates, two other common types of templates are table templates and style templates. A table template describes how to display the output for an output object that is rendered as a table. A style template provides formatting information for visual aspects of your SAS output, including both tables and graphs. In most applications, you do not have to modify the templates that are supplied by SAS. However, when customization is necessary, you can modify the default template with the template language and PROC TEMPLATE.

Compiled templates are stored in a template store, which is a type of item store. (An item store is a special type of SAS file.) The default templates supplied by SAS are stored in the Sashelp.Tmplmst template store. If you are using the SAS windowing environment, an easy way to display, edit, and save your templates is by using the Templates window. For an introduction to the graph template language, see Kuhfeld (2010).

For detailed information about managing templates, see the SAS Output Delivery System: User's Guide and the SAS Graph Template Language: User's Guide. For details about the syntax of the graph template language, see the SAS Graph Template Language: Reference.