About This Book

Purpose

Analysis of data is easier when graphs are integrated into the analysis process. With increasing amount of data to be analyzed, graphical views of the data can help in planning the analysis phase of the project. Results of the analysis are easier to understand when they are delivered in a graphical form, where the data and the derived statistical information can be displayed together.

In many use cases you can get by with a simple bar chart or a scatter plot. But often you need sophisticated graphs with complex layouts to understand the trends and see the associations in the data. These include graphs with data overlaid with the derived statistics and tabular information, classification panels by multiple class variables, scatter plot matrices of multiple measures and ad-hoc layout of dissimilar graphs necessary to display the information using multiple representations of data, often on a uniform scale.

To create such graphs you need a language to systematically describe the complex layouts and the relationships between the different parts of the graph. Individual graphs could be created using extensive annotate functionality, but such graphs are difficult to adapt to different situations, hard to build, and hard to maintain. This is where the Graph Template Language (GTL) excels.

GTL can do a lot but it has a significant learning curve. This book helps you get started with learning this significant topic in small steps. You can start building graphs in just minutes and move up to more complex graphs one step at a time. This book will help you get a firm grasp on the topic, and provide you the information you need to grow on your own.

Is This Book for You?

GTL has a structured and logical syntax that provides a high level of features. This comes with some complexity.

Often you just need a simple graph quickly. For such situations, the tools mentioned below may be more suitable to your needs. These tools use the GTL behind the scenes to create the graph. They expose some of the GTL features through a simpler interface, allowing faster creation of the graphs. These are:

• The Statistical Graphics (SG) procedures.

• ODS Graphics Designer.

However, both of these tools cover only a part of the features built into GTL. Once you reach the limits of these tools, you will need to move up to GTL. And to get started with GTL this book is for you.

The automatic graphs created by the SAS analytical procedures use precompiled GTL templates written by the SAS procedure writers and shipped with SAS. To customize any of these graphs, you will need to have a good understanding of GTL to edit these templates.

Prerequisites

Some familiarity with SAS is necessary to be able to use this material. You do not need to be an expert SAS DATA step programmer or familiar with many SAS procedures. This book is suitable for all levels of SAS users.

Software and Examples Used in this Book

GTL was first released with SAS 9.2. Prior to SAS 9.3 GTL was available with SAS/GRAPH software. From SAS 9.3 onwards GTL is available as part of the Base SAS product.

All the graph examples used in this book were created using SAS 9.3. Some graphs that illustrate a specific new feature use SAS 9.4. In such cases a comment is added to the code indicating that it is a SAS 9.4 feature.

The data for the graphs mostly comes from the data sets included in the SASHELP library. The graphs displayed in this book are small in size to fit the format. To keep the graph from getting too cluttered the data is often subset.

At other times, special data is needed to illustrate some graph feature. In this case, the appropriate data is created using a SAS program. All data sets used to create the graphs are available as a SAS program that can be down loaded from the author’s page at: http://support.sas.com/matange.

Example Code and Data

You can access the example code and data for this book by linking to its author page at http://support.sas.com/matange. Select “Example Code and Data” to display the SAS programs that are included in this book.

For an alphabetical listing of all books for which example code and data is available, see http://support.sas.com/bookcode. Select a title to display the book’s example code.

If you are unable to access the code through the Web site, send e-mail to [email protected].

Output and Graphics

All the graphs in this book are created by using the LISTING destination with the default LISTING style. Sometimes other styles are used for illustrative purposes.

Most of the graphs in the book occupy a region that is 4 inches wide and 2.5 inches high. To create graphs that are suitable for display in the book, the graphs are rendered to a width of 4 inches and a height of 2.5 inches. This creates graphs with text that is fairly legible. The graphs are rendered as PNG files at 300 dpi.

Additional Resources

SAS offers a rich variety of resources to help build your SAS skills and explore and apply the full power of SAS software. Whether you are in a professional or academic setting we have learning products that can help you maximize your investment in SAS.

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