SAS Macro Programs: canplot

The canplot macro ( get canplot.sas)

Canonical discriminant structure plot

Method

Other designs may be handled either by (a) coding factor combinations 'interactively', so, e.g., the combinations of A*B are represented by a GROUP variable, or (b) by applying the method to adjusted response vectors (residuals) with some other predictor (class or continuous) partialled out. The latter method is equivalent to analysis of the residuals from an initial PROC GLM step, with the effects to be controlled or adjusted for as predictors.

e.g., to examine Treatment, controlling for Block and Sex,

   proc glm data=..;
    model Y1-Y5 = block sex;
    output out=resids
       r=E1-E5;
  %canplot(data=resids, var=E1-E5, class=Treat, ... );

Usage

The interpretation of the angles betweeen variable vectors relies on the units for the horizontal and vertical axes being made equal (so that 1 data unit measures the same length on both axes. The axes should be equated either by using the GOPTIONS HSIZE= VSIZE= options, or using the macro HAXIS= and VAXIS= parameters and AXIS statements which specify the LENGTH= value for both axes.

The current version now uses the equate macro if the HAXIS= and VAXIS= arguments are not supplied.

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

   %canplot(data=inputdataset, var=predictors, class=groupvariable..., )

Parameters

DATA=_LAST_

The name of the input dataset. If not specified, the most recently created dataset is used.

CLASS=

The name of one class (group) variable

VAR=

List of classification (predictor) variables

SCALE=AUTO

Scale factor for variable vectors in plot. The variable vectors are multiplied by the SCALE= value, which should be specified (perhaps by trial and error) to make the vectors and observations fill the same plot region. If SCALE=AUTO or SCALE=0, the program estimates a scale factor from the ratio of the maximum distance to the origin in the observations relative to the variables.

CONF=.95

Confidence probability for canonical means

OUT=_DSCORE_

The name of the output data set containing discriminant scores

ANNO=_DANNO_

Output data set containing annotations

PLOT=YES

YES to produce the plot, or NO to suppress the plot

HAXIS=

The name of an optional AXIS statement for the horizontal axis. The HAXIS= and VAXIS= arguments may be used to equate the axes in the plot so that the units are the same on the horizontal and vertical axes.

VAXIS=

The name of an optional AXIS statement for the vertical axis.

NAME=CANPLOT

name for graphic catalog entry

COLORS=RED GREEN BLUE BLACK PURPLE YELLOW BROWN ORANGE

List of colors to be used for groups

SYMBOLS=+ SQUARE STAR - PLUS : $ =

List of symbols to be used for the various groups (levels of the CLASS= variable).

Example

goptions vsize=3.2 in hsize=7.5in  htext=2;
%include data(iris);
		
title h=2.5 'Iris Data - Canonical Discriminant Plot';
axis1 order=(-10 to 10 by 2);
axis2;
legend1 value=(h=2);
%canplot(
     data=iris, class=species,
     var=sepallen sepalwid petallen petalwid,
     haxis=axis1, vaxis=axis2, legend=legend1, hsym=1.5,
     colors=red blue black, scale=3.5);

See also