The GPLOT Procedure

Example 8: Plotting Three Variables

Procedure features:

PLOT classification variable

Other features:

AXIS statement

SYMBOL statement

RUN-group processing

Sample library member:

GR21N08

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This example shows that when your data contain a classification variable that groups the data, you can use a plot request of the form y-variable*x-variable=third-variable to generate a separate plot for every formatted value of the classification variable, which in this case is CITY. With this type of request, all plots are drawn on the same graph and a legend is automatically produced and explains the values of third-variable. The default legend uses the variable name CITY for the legend label and the variable values for the legend value descriptions. Because no LEGEND definition is used in this example, the font and height of the legend label and the legend value descriptions are set by the graphics options FTEXT= and HTEXT=. Height specifications in the SYMBOL statement do not affect the size of the symbols in the legend values.

This example then modifies the plot request. As shown in the following output, the plot is enhanced by using different symbol definitions for each plot line, changing axes labels, and scaling the vertical axes differently.

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libname reflib 'SAS-data-library'; goptions reset=global gunit=pct border cback=white colors=(black blue green red) ftitle=swissb ftext=swiss htitle=6 htext=3;

data reflib.citytemp; input month faren city $; datalines; 1 40.5 Raleigh 1 12.2 Minn 1 52.1 Phoenix ...more data lines... 12 41.2 Raleigh 12 18.6 Minn 12 52.5 Phoenix ;

title1 'Average Monthly Temperature'; footnote1 j=l ' Source: 1984 American Express'; footnote2 j=l ' Appointment Book' j=r 'GR21N08(a) ';

symbol1 interpol=join value=dot height=3;

proc gplot data=reflib.citytemp; plot faren*month=city / hminor=0; run;

footnote2 j=l ' Appointment Book' j=r 'GR21N08(b) ';

symbol1 color=green interpol=spline width=2 value=triangle height=3; symbol2 color=blue interpol=spline width=2 value=circle height=3; symbol3 color=red interpol=spline width=2 value=square height=3;

axis1 label=none value=('JAN' 'FEB' 'MAR' 'APR' 'MAY' 'JUN' 'JUL' 'AUG' 'SEP' 'OCT' 'NOV' 'DEC') offset=(2) width=3; axis2 label=('Degrees' justify=right 'Fahrenheit') order=(0 to 100 by 10) width=3;

legend1 label=none value=(tick=1 'Minneapolis');

plot faren*month=city / haxis=axis1 hminor=0 vaxis=axis2 vminor=1 caxis=red legend=legend1; run; quit;

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