GPLOT Procedure

Example 4: Plotting Two Variables

Features:

PLOT statement options :: HAXIS=; HMINOR=; REGEQN; VAXIS=

Other features:

GOPTIONS statement option: BORDER

SYMBOL statement

Sample library member:

GPLVRBL1

In this example, the PLOT statement uses a plot request of the type y-variable*x-variable to plot the variable HEIGHT against the variable WEIGHT. The plot shows that weight generally increases with size.

The second example then requests the same plot with some modifications. As shown by the second output display, the second plot request specifies a regression analysis with confidence limits, and scales the range of values along the vertical and horizontal axes. It also displays the regression equation specified for the SYMBOL statement. Because the procedure supports RUN-group processing, you do not have to repeat the PROC GPLOT statement to generate the second plot.

Two-Variable Plot with Regression Analysis

Program

goptions reset=all border;

title "Study of Height vs Weight";
footnote1 j=l "Source: T. Lewis & L. R. Taylor";
footnote2 j=l "Introduction to Experimental Ecology";

proc gplot data=sashelp.class;
   plot height*weight;
run;

footnote1; /* this clears footnote1 and footnote2 */

symbol1 interpol=rcclm95
       value=circle
       cv=darkred
       ci=black
       co=blue
       width=2;

   plot height*weight / haxis=45 to 155 by 10
                        vaxis=48 to 78 by 6
                        hminor=1
                        regeqn;
run;
quit;

Program Description

Set the graphics environment.

goptions reset=all border;

Define title and footnotes.

title "Study of Height vs Weight";
footnote1 j=l "Source: T. Lewis & L. R. Taylor";
footnote2 j=l "Introduction to Experimental Ecology";

Generate a default scatter plot.

proc gplot data=sashelp.class;
   plot height*weight;
run;

Clear the footnotes to make room for the regression equation.

footnote1; /* this clears footnote1 and footnote2 */

Define symbol characteristics. The INTERPOL= option specifies a cubic regression analysis with confidence limits for mean predicted values. The VALUE=and CV= options specify a plot symbol and color. The CI=, CO=, and WIDTH= options specify colors and a thickness for the interpolation and confidence-limits lines.

symbol1 interpol=rcclm95
       value=circle
       cv=darkred
       ci=black
       co=blue
       width=2;

Generate scatter plot with regression line. The HAXIS= and VAXIS= options define the range of axes values. The HMINOR= option specifies one minor tick mark between major tick marks. The REGEQN option displays the regression equation specified on the SYMBOL1 statement.

   plot height*weight / haxis=45 to 155 by 10
                        vaxis=48 to 78 by 6
                        hminor=1
                        regeqn;
run;
quit;