ODS Graphics Template Modification

This section shows you how to customize colors, line attributes, and marker symbol attributes by modifying a graph template. In the QQPlot template definition shown previously, the SCATTERPLOT statement specifies a scatter plot of normal quantiles versus ordered standardized residuals. The attributes of the marker symbol in the scatter plot are specified by: MarkerAttrs=GraphDataDefault. This is a reference to the style element GraphDataDefault. For more information, see the section ODS Style Elements and Attributes in Chapter 21: Statistical Graphics Using ODS.

The actual value of the marker symbol depends on the style that you are using. In this case, since the HTMLBLUE style is used, the marker symbol is a circle. You can specify a filled circle as the marker symbol by overriding the symbol portion of the style specification as follows: MarkerAttrs=GraphDataDefault(symbol=CircleFilled).

The value of the SYMBOL= option can be any valid marker symbol or a reference to a style attribute of the form style-element:attribute. It is recommended that you use style attributes because they are chosen to provide consistency and appropriate emphasis based on display principles for statistical graphics. If you specify values directly in a template, you are overriding the style and you run the risk of creating a graph that is inconsistent with the style template. For more information about the syntax of the Graph Template Language and style elements for graphics, see the SAS Graph Template Language: Reference and the SAS Output Delivery System: User's Guide.

Similarly, you can change the line color and pattern with the LINEATTRS= option in the LINEPARM statement. The LINEPARM statement displays a straight line specified by slope and intercept parameters. The following option changes the color of the line to red and the line pattern to dashed, by overriding those aspects of the style specification: LineAttrs=GraphReference(color=red pattern=dash). To see the results, submit the modified template definition and the PROC ROBUSTREG statements as follows to create Output 22.1.3:

proc template;
   define statgraph Stat.Robustreg.Graphics.QQPlot;
      notes "Q-Q Plot for Standardized Robust Residuals";
      dynamic _DEPLABEL Residual _byline_ _bytitle_ _byfootnote_;
      BeginGraph;
         entrytitle "Analysis of Residuals";
         Layout Overlay /
            yaxisopts=(label=("Standardized Robust Residual for " _DEPLABEL))
            xaxisopts=(label="Quantile");
            SCATTERPLOT y=eval (SORT(DROPMISSING(RESIDUAL))) x=eval (
               PROBIT((NUMERATE(SORT(DROPMISSING(RESIDUAL))) -0.375)/(0.25 +
               N(RESIDUAL)))) / primary=true
               markerattrs=GraphDataDefault(symbol=CircleFilled)
               rolename=(q=eval(
               PROBIT((NUMERATE(SORT(DROPMISSING(RESIDUAL))) -0.375)/(0.25 +
               N(RESIDUAL)))) s=eval (SORT(DROPMISSING(RESIDUAL))))
               tip=(q s) tiplabel=(q= "Quantile" s="Residual");
            lineparm slope=eval (STDDEV(RESIDUAL)) Y=eval (MEAN(RESIDUAL)) X=0 /
               clip=false lineattrs=GraphReference(color=red pattern=dash)
               extend=true;
         EndLayout;
         if (_BYTITLE_)
            entrytitle _BYLINE_ / textattrs=GRAPHVALUETEXT;
         else
            if (_BYFOOTNOTE_)
               entryfootnote halign=left _BYLINE_;
            endif;
         endif;
      EndGraph;
   end;
run;

ods graphics on;

proc robustreg data=stack plots=qqplot;
   ods select QQPlot;
   model y = x1 x2 x3;
run;

Alternatively, you can replay the plot with PROC DOCUMENT, as in Example 21.4 in Chapter 21: Statistical Graphics Using ODS.