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PROC TREE Statement

PROC TREE < options > ;

The options that can appear in the PROC TREE statement are summarized in the following table.

CFRAME=color

specifies a color for the frame, which is the rectangle bounded by the axes.

DATA=SAS-data-set

specifies the input data set defining the tree. If you omit the DATA= option, the most recently created SAS data set is used.

DESCENDING

DES

reverses the sorting order for the SORT option.

DESCRIPTION=entry-description

specifies a description for the graph in the GOUT= catalog. The default is "Proc Tree Graph Output."

DISSIMILAR

DIS

implies that the values of the HEIGHT variable are dissimilarities; that is, a large height value means that the clusters are very dissimilar or far apart.

If neither the SIMILAR nor the DISSIMILAR option is specified, PROC TREE attempts to infer from the data whether the height values are similarities or dissimilarities. If PROC TREE cannot tell this from the data, it issues an error message and does not display a tree diagram.

DOCK=n

causes observations in the OUT= data set assigned to output clusters with a frequency of n or less to be given missing values for the output variables CLUSTER and CLUSNAME. If the NCLUSTERS= option is also specified, DOCK= also prevents clusters with a frequency of n or less from being counted toward the number of clusters requested by the NCLUSTERS= option. By default, DOCK=0.

FILLCHAR='c'

FC='c'

specifies the character to display between leaves that are not joined into a cluster. The character should be enclosed in single quotes. The default is a blank. The LINEPRINTER option must also be specified.

GOUT=<libref.>member-name

specifies the catalog in which the generated graph is stored. The default is WORK.GSEG.

HAXIS=AXISn

specifies the AXISn statement used to customize the appearance of the horizontal axis.

HEIGHT=name

H=name

specifies certain conventional variables to be used for the height axis of the tree diagram. For many situations, the only option you need is the HEIGHT= option. Valid values for name and their meanings are as follows:

HEIGHT | H

specifies the _HEIGHT_ variable.

LENGTH | L

defines the height of each node as its path length from the root. This can also be interpreted as the number of ancestors of the node.

MODE | M

specifies the _MODE_ variable.

NCL | N

specifies the _NCL_ (number of clusters) variable.

RSQ | R

specifies the _RSQ_ variable.

See also the "HEIGHT Statement" section, which can specify any variable in the input data set to be used for the height axis. In rare cases, you may need to specify either the DISSIMILAR option or the SIMILAR option.

HORDISPLAY=RIGHT

specifies that the graph is to be oriented horizontally, with the leaf nodes on the right side, when the HORIZONTAL option is also specified. By default, the leaf nodes are on the left side.

HORIZONTAL

HOR

orients the tree diagram with the height axis horizontal and the root at the left. The leaf nodes are on the side specified in the HORDISPLAY= option. If you do not specify the HORIZONTAL option, the height axis is vertical, with the root at the top. When the tree takes up more than one page and is viewed on a screen, horizontal orientation can make the tree diagram considerably easier to read.

HPAGES=n1

specifies that the original graph is to be enlarged to cover n1 pages. If you also specify the VPAGES=n2 option, the original graph is enlarged to cover n1 ×n2 graphs. For example, if HPAGES=2 and VPAGES=3, then the original graph is generated followed by 2 ×3 = 6 more graphs. In these six graphs, the original is enlarged by a factor of 2 in the horizontal direction and by a factor of 3 in the vertical direction. The graphs are generated in left-to-right and top-to-bottom order.

INC=n

specifies the increment between tick values on the height axis. If the HEIGHT variable is _NCL_, the default is usually 1, although a different value can be specified for consistency with other options. For any other HEIGHT variable, the default is some power of 10 times 1, 2, 2.5, or 5.

JOINCHAR='c'

JC='c'

specifies the character to display between leaves that are joined into a cluster. The character should be enclosed in single quotes. The default is X. The LINEPRINTER option must also be specified.

LEAFCHAR='c'

LC='c'

specifies a character to represent clusters having no children. The character should be enclosed in single quotes. The default is a period. The LINEPRINTER option must also be specified.

LEVEL=n

specifies the level of the tree defining disjoint clusters for the OUT= data set. The LEVEL= option also causes only clusters between the root and a height of n to be displayed. The clusters in the output data set are those that exist at a height of n on the tree diagram. For example, if the HEIGHT variable is _NCL_ (number of clusters) and LEVEL=5 is specified, then the OUT= data set contains five disjoint clusters. If the HEIGHT variable is _RSQ_ (R²) and LEVEL=0.9 is specified, then the OUT= data set contains the smallest number of clusters that yields an R² of at least 0.9.

LINEPRINTER

specifies that the generated report is to be displayed using line printer graphics.

LINES=(<COLOR=color><WIDTH=n><DOTS>)

enables you to specify both the color and the thickness of the lines. In addition, a dot can be drawn at each leaf node. Note that if the frame and the lines are specified to be the same color, PROC TREE selects a different color for the lines.

LIST

lists all the nodes in the tree, displaying the height, parent, and children of each node.

MAXHEIGHT=n

MAXH=n

specifies the maximum value displayed on the height axis.

MINHEIGHT=n

MINH=n

specifies the minimum value displayed on the height axis.

NAME=name

specifies the entry name for the generated graph in the GOUT= catalog. Note that each time another graph is generated with the same name, the name is modified by appending a number to make it unique.

NCLUSTERS=n

NCL=n

N=n

specifies the number of clusters desired in the OUT= data set. The number of clusters obtained may not equal the number specified if (1) there are fewer than n leaves in the tree, (2) there are more than n unconnected trees in the data set, (3) a multi-way tree does not contain a level with the specified number of clusters, or (4) the DOCK= option eliminates too many clusters.

The NCLUSTERS= option uses the _NCL_ variable to determine the order in which the clusters are formed. If there is no _NCL_ variable, the height variable (as determined by the HEIGHT statement or HEIGHT= option) is used instead.

NTICK=n

specifies the number of tick intervals on the height axis. The default depends on the values of other options.

NOPRINT

suppresses the display of the tree. Specify the NOPRINT option if you want only to create an OUT= data set. Note that this option temporarily disables the Output Delivery System (ODS). For more information, see Chapter 14, "Using the Output Delivery System."

OUT=SAS-data-set

creates an output data set that contains one observation for each object in the tree or subtree being processed and variables called CLUSTER and CLUSNAME showing cluster membership at any specified level in the tree. If you specify the OUT= option, you must also specify either the NCLUSTERS= or LEVEL= option in order to define the output partition level. If you want to create a permanent SAS data set, you must specify a two-level name (refer to "SAS Data Files" in SAS Language Reference: Concepts.

PAGES=n

specifies the number of pages over which the tree diagram (from root to leaves) is to extend. The default is 1. The LINEPRINTER option must also be specified.

POS=n

specifies the number of column positions on the height axis. The default depends on the value of the PAGES= option, the orientation of the tree diagram, and the values specified by the PAGESIZE= and LINESIZE= options. The LINEPRINTER option must also be specified.

ROOT='name'

specifies the value of the NAME variable for the root of a subtree to be diplayed if you do not want to display the entire tree. If the OUT= option is also specified, the output data set contains only objects belonging to the subtree specified by the ROOT= option.

SIMILAR

SIM

implies that the values of the HEIGHT variable are similarities; that is, a large height value means that the clusters are very similar or close together.

If neither the SIMILAR nor the DISSIMILAR option is specified, PROC TREE attempts to infer from the data whether the height values are similarities or dissimilarities. If PROC TREE cannot tell this from the data, it issues an error message and does not display a tree diagram.

SORT

sorts the children of each node by the HEIGHT variable, in the order of cluster formation. See the DESCENDING option.

SPACES=s

S=s

specifies the number of spaces between objects on the output. The default depends on the number of objects, the orientation of the tree diagram, and the values specified by the PAGESIZE= and LINESIZE= options. The LINEPRINTER option must also be specified.

TICKPOS=n

specifies the number of column positions per tick interval on the height axis. The default value is usually between 5 and 10, although a different value can be specified for consistency with other options.

TREECHAR='c'

TC='c'

specifies a character to represent clusters with children. The character should be enclosed in single quotes. The default is X. The LINEPRINTER option must also be specified.

VAXIS=AXISn

specifies that the AXISn statement be used to customize the appearance of the vertical axis.

VPAGES=n2

specifies that the original graph is to be enlarged to cover n2 pages. If you also specify the HPAGES=n1 option, the original graph is enlarged to cover n1 ×n2 pages. For example, if HPAGES=2 and VPAGES=3, then the original graph is generated followed by 2 ×3 = 6 more graphs. In these six graphs, the original is enlarged by a factor of 2 in the horizontal direction and by a factor of 3 in the vertical direction. The graphs are generated in left-to-right and top-to-bottom order.

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