SG Annotation Data Sets :: SAS(R) 9.3 ODS Graphics: Procedures Guide, Third Edition

About the SG Annotation Data Set

Once you have determined which annotation you want and how you want it to appear in the output, you can create the SG annotation data set. This data set contains the commands for creating one or more annotation elements. The annotations drawn by these commands can be added to SG procedure output.

Each observation represents a command to draw an annotation element or to continue an element. Reserved keywords are used for functions that specify the drawing operation.

You create the data set using the same methods that you use to create any SAS data set. The main distinctions are that the SG annotation data set uses reserved keywords for its variable names, and each observation represents a command to draw an annotation element.

Note: The most commonly used method for creating data sets is with a DATA step. For more information about the DATA step, see SAS Language Reference: Concepts.

Here is an example of an SG annotation data set named LINE. The observations in this data set contain the commands that create a blue text label and a blue line.

LINE SG Annotation Data Set

A blank denotes a missing value for a character variable. A '.' denotes a missing value for a numeric variable.

Each observation in this data set contains complete instructions for drawing an annotation. The value of the FUNCTION variable determines what the observation does. Other variables control how the function is performed.

This list describes each observation in LINE and the task that it performs:

This instruction writes a blue text inset at position (20,70). The value of the FUNCTION variable (TEXT) tells the program what to do. The values of the coordinate variables X1 and Y1 tell where to do it. The value of the attribute variable TEXTCOLOR specifies the color of the text inset.

Note: The default drawing space for both observations is the graph area. For more information about drawing spaces, see Controlling the Drawing Space.
This instruction draws a blue line that begins at position (10,60) and ends at (99,60). The value of the FUNCTION variable (LINE) tells the program what to do. The values of the coordinate variables X1, Y1, X2, and Y2 tell where to do it. The value of the attribute variable LINECOLOR specifies the color of the line.

The following figure shows the blue text and line annotations created by the LINE data set displayed with an SGPLOT procedure that specifies a scatter plot.

LINE SG Annotation Output

Here is the SAS code step that creates the LINE data set and generates the graph.

data Line;
  infile datalines dlm='#';
  length label $ 27
         textcolor $ 9
         linecolor $ 9;

  input function $ x1 y1 label x2 y2 textcolor linecolor;
datalines;
text # 20 # 70 # Average Height 62 Inches # . # . # blue # 
line # 10 # 60 #   # 99 # 60 #   # blue
;
run;

proc sgplot data=sashelp.class sganno=Line;
 scatter x=weight y=height;
run;

SG Annotation Variables

When an SG annotation data set is processed, the SG procedure looks at the values of specific variables in order to draw annotation elements. Variables in the SG annotation data set have predefined names. In each observation, the procedure looks only for variables with those names. Other variables can be present, but they are ignored.

The variables can be categorized into the following main types:

A FUNCTION variable specifies which annotation element to draw. For more information, see SG Annotation Functions.
Position variables specify the point or points at which to draw the graphics element.
Coordinate system variables specify the drawing space to use for the annotation. For more information, see Controlling the Drawing Space.
Attribute variables specify the characteristics of the graphics element (for example, color, size, line style, text font).

All variables are described in the context of the functions that support the variables. For more information about the functions, see SG Annotation Function Dictionary.

SG Annotation Functions

In an SG annotation data set, the FUNCTION variable accepts a set of predefined values (functions) that insert annotation elements into the graph. The value of the FUNCTION variable specifies what drawing action the observation performs. These functions act in conjunction with other variables that determine where and how to perform the action.

The following table summarizes the functions:

Summary of SG Annotation Functions

Function	Description
ARROW	Draws an arrow annotation. For more information, see ARROW Function.
IMAGE	Specifies a graphic file to use for an image annotation. For more information, see IMAGE Function.
LINE	Draws a line annotation. For more information, see LINE Function.
OVAL	Draws an oval or circle annotation. For more information, see OVAL Function.
POLYCONT	Continues drawing a polygon that was begun with the POLYGON function, or a line that was begun with the POLYLINE function. For more information, see POLYCONT Function.
POLYGON	Specifies the beginning point of a polygon. For more information, see POLYGON Function.
POLYLINE	Specifies the beginning point of a polyline, which is a connected series of line segments. For more information, see POLYLINE Function.
RECTANGLE	Draws a rectangle or square annotation. For more information, see RECTANGLE Function.
TEXT	Places text in the graph output. For more information, see TEXT Function.
TEXTCONT	Continues a text string. For more information, see TEXTCONT Function.