PROC GPLOT

GPLOT is used to make two dimensional scatter-plots.

General Syntax:

proc gplot data=data-set options;

plot y-variable*x-variable/options;

run;

quit;

Multiple Plot Calls in a Plot Statement

Multiple y-variable*x-variable calls are permitted in a plot statement, each generating a separate plot by default.• In the PROC GPLOT statement the uniform

option gives each plot the same axis scales.

• Assuming a common x-variable, the overlay option (in the plot statement) will cause the plots to be displayed on the same graph.

• A legend is created for overlay plots if the legend=legendn option is included.

Multiple Plot Calls in a Plot Statement

proc gplot data=save.padgett;plot totmass*plantht;/*now do more than one plot at a time*/

proc gplot data=save.padgett;plot totmass*plantht bllenavg*plantht;

/*we get two different plot*/

PLOT and PLOT2

The PLOT2 statement allows for a second vertical axis to be displayed. Conditions:• The x-variables in PLOT and PLOT2 must be

the same.

• Differing vaxis specifications can be made for each.

PLOT and PLOT2

/*to get two different y-axes, try this…/*

proc gplot data=save.padgett;plot lleaves*plantht; /*left*/

plot2 bllenavg*plantht;/*right*//*we get two plots on the same horizontal axis, but two different y-axes*/

Plots According to Third Variable

Plots of the form y-variable*x-variable=z-variable produces a plot for each level of the z-variable.• Overlaying of plots is automatic.

• A legend is produced automatically.

• This legend can be modified in a similar manner to that of legends in bar charts.

Plots According to Third Variable

proc gplot data=save.padgett;plot totmass*plantht=marsh/legend=legend1;/*distinguishes the plotting points by marsh and produces a legend so we can tell which is which…*/

/* modify the legend as below… */legend1 down=2 position=(top left inside) frame cborder=blue cframe=gray cshadow=red;

LEGEND Statement Options

across=n —Legend is created with n entries per row.

down=n —Legend is created with n entries per column

• Only one of ACROSS or DOWN should be specified.

LEGEND Statement Options

position=(P1 P2 P3) —Legend is positioned based on parameters specified.• Bottom, middle or top: Sets vertical position.

• Left, center or right: Sets horizontal position.

• Inside or outside: Places legend inside or outside the graph area.

• Default is (bottom center outside).

LEGEND Statement Options

mode=reserve|protect|share —Controls how space is allocated to the plot and the legend.• Reserve: Legend is allocated its own space in the

output area. This is the default; however, it cannot be used for position= (inside).

• Protect: The legend is “protected” from the plot—it is drawn over the plot. This is the default when position= (inside).

• Share: Graphics are drawn over the legend if there is any intersection.

LEGEND Statement Options

frame—Draws a frame around the legend in the first default color.

cborder= —Draws a frame around the legend in the specified color.

cframe= —Specifies the background color of the legend (or “fills” the frame).

cshadow= —Places a shadow “behind” the legend in the specified color.

LEGEND Statement Options

shape= —Controls appearance of the legend symbols. Specifications include:• bar(width, height)

• line(length)

• symbol(width, height)

label=(text-attributes ‘text’ ) —Defines the legend label text.

value=(text-attributes-n ‘text-n’ ) —Defines the text associated with each legend symbol.

LEGEND Statement Options Text attribute options include:

• c= Text color.

• f= Text font.

• h= Text height.

• t= (value= option only) Legend entry to be modified. Must precede the attributes being changed for that entry.

• position= (label= option only) Positions legend label. Same options as legend position except for inside/outside (legend label is always inside).

Axis Modification

As an option in the plot statement (after the / ) the user can specify haxis=axisn and/or vaxis=axisn to associate each axis with an axis statement.

A plot2 statement may include a vaxis=axisn specification as well.

Axis Modification

proc gplot data=save.projects;plot equipmnt*jobtotal/legend=legend1haxis=axis1 vaxis=axis2;where stname in (‘NC’ ‘SC’ ‘VA’);legend1 down=2 position=(top left inside) frame cborder=blue cframe=gray cshadow=red;

axis1 label=(“Equipment Cost” c=blueh=2 f=swissb) minor=none;axis2 label=(“Total Costs”);

The AXIS Statement

Axis statement options include:• c= (color=): Specifies the color of the axis

lines, tick marks and text.

• width= Specifies the thickness of the axis line.

• order=(value list or start to stop by increment): Specifies the data values

corresponding to the major tick marks.

• offset=(n1,n2): Specifies the space from the start of the axis to the first tick and the

end of the axis from the last tick, respectively.

The AXIS Statement

Axis statement options include:• label=(text-options ‘text’) or NONE: Defines

the axis label and its attributes.

• value=(text-options-n ‘text-n’) or NONE: Defines major tick labels and attributes. Can

be done as a group or one at a time.

The AXIS Statement

Attributes that can be specified within the label= and value= options:• c= Text color.

• f= Text font.

• h= Text height.

• a= Angle of the text string.

• r= Rotation of individual characters.

• t= (value= option only) Tick mark to be modified. Must precede the attributes being

changed for that tick.

Enhancing the Plot Area

The SYMBOL statement:• Modifies the plotting symbol and related items

symboln options;

• n can range from 1 to 255.

• If n is omitted it is taken as 1 by default.

• SYMBOL statements are global—remain in effect until altered.

• They are applied across the current color list if no color is specified.

Some SYMBOL Statement Options

v= (value=): Specifies the plotting symbol.

f= (font=): Specifies the font from which the plotting symbol is selected.

cv= Symbol color. h= (height=): Specifies the height of the

symbol [in cells]. pointlabel places y-value near each

point

Inheritance in SYMBOL Statements

SYMBOL statements are global, some behaviors:• Unmodified options will be inherited in

subsequent definitions of a symbol statement.

• Modifications to a symbol statement (e.g. symbol2) does not alter symbol statements with other numbers.

• The statement goptions reset=symbol cancels all currently defined symbol statements.

Symbols

Default symbol specifications and results:

Symbols

Write 3 symbol statements to change the colors, shapes,sizes of the 3 plotting symbols for “NC”, “SC” and “VA”

Go back to Padgett data and experiment with symbol statements

The GFONT Procedure

You can view a SAS/GRAPH font using PROC GFONT. The typical syntax will be:proc gfont name=font nobuild showroman

ctext=color ;run;

This code will display the font symbols with their standard counterparts. Fonts can be found in the fonts catalog in the SAShelp library.

Plot Lines

i= (interpol=): Specifies the interpolation method. Some of these include:• join: Joins the points with line segments

(“connect the dots”).

• sm##: Draws a smooth curve through the points, ## is a number that determines the level of smoothness (higher=smoother).

• needle: Draws vertical lines from the data to 0 (or the minimum value if all are

greater than 0).

Plot Lines

• R<type><0><CLM or CLI<##>> where:• type is L, Q or C corresponding to linear,

quadratic or cubic regression, respectively.

• 0 forces the regression through the origin.

• CLM and CLI specifies display of confidence limits for average (mean) predicted

values and individual predictions.

• ## specifies the confidence level between 50 and 99.

Plot Lines

The SYMBOL statement can be used to control plot lines:• l= (line=): Specifies a line type (various types

of dashed lines). Valid values go from 1 to 46.

• w= (width=): Specifies the line thickness.

• ci= Sets the line color.

• c= (color=): Sets colors for both lines and symbols.

Plot Lines

Now try your hand at some of the interpolation methods - see if you can find the best smoothing for total mass against plantht by marsh in the Padgett data…