coplot Construct a conditioning plot - plots of y * x | z coplot

SAS Macro Programs: coplot

$Version: 1.3 (13 Jun 2000)
Michael Friendly
York University

The coplot macro ( [download] get coplot.sas)

Construct a conditioning plot - plots of y * x | z

The COPLOT macro plots a collection of XY plots, for subsets of a data set conditioned by a GIVEN= variable. These help to show how the relation between X and Y varies with the given variable. A poor-man's version of the Trellis display.

Usage

The COPLOT macro is defined with keyword parameters. The X=, Y=, and GIVEN= parameters are required. Either or both of the ROWS= and COLS= parameters may be used to arrange the collection of plots in a rectangular grid.

The arguments may be listed within parentheses in any order, separated by commas. For example: 

  %coplot(x=weight, y=mpg, given=Origin);

Parameters

DATA=
Name of the data set to be plotted [Default: DATA=_LAST_]
X=
Horizontal variable in each plot
Y=
Vertical variable in each plot
GIVEN=
The name of the slicing variable. May be a numeric or character variable. If numeric, it it treated as continuous, and sliced as determined by the SLICES and OVERLAP parameters. A character GIVEN= variable is treated as discrete, with no OVERLAP between slices.
GROUP=
Grouping variable (determines the plot symbol/color)
SLICES=
Number of slices of the GIVEN= variable [Default: SLICES=4]
OVERLAP=
Allowed overlap between slices [Default: OVERLAP=0.25]
ROWS=
Number of rows in the panel plot. If neither ROWS= nor COLS= are specified, both values are calculated from the SLICES= value to give a square-ish display. If only one of ROWS= or COLS= is specified, the other value is calculated.
COLS=
Number of columns in the panel plot.
INTERP=
Plot interpolation method used in each panel. E.g., INTERP=RL fits and draws a linear regression line. [Default: INTERP=NONE]
HSYM=
Height of plot symbols and value labels in the plots.
GPANEL=
Height of the given panel, in % of the plot size. If GPANEL=0, the given panel is suppressed. [Default: GPANEL=0]
SYMBOLS=
List of symbols to use for for groups defined by the GROUP= variable. [Default: SYMBOLS=%STR(CIRCLE SQUARE + : $ = X _ Y)]
COLORS=
List of colors to use for for groups. [Default: COLORS=BLACK RED GREEN BLUE BROWN YELLOW ORANGE PURPLE]
GOUT=
Name of the output graphics catalog. [Default: GOUT=GSEG]

Limitations

The plots are drawn separately, then composed into one figure with PROC GREPLAY (the PANELS macro). As a result:

Example

%include macros(coplot);        *-- or include in an autocall library;

data test;
  drop i;
  do i=1 to 60;
     gp = 1 + mod(i,4);
     x1 = round( 100*uniform(0));
     x2 = round( 100*uniform(0)) + x1 + 4*gp;
     x3 = round( 100*uniform(0)) - x1 + x2 - 4*gp;
     output;
     end;

%coplot(data=test,
	x=X1, y=X2, given=X3, slices=4, overlap=.25,
	interp=rl, rows=1);

See also

panels
scatmat