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The GMAP Procedure

CHORO Statement

Creates two-dimensional maps in which values of the specified response variables are represented by varying patterns and colors.

Requirements: At least one response variable is required. You must use the ID statement in conjunction with the CHORO statement.
Global statements: FOOTNOTE, LEGEND, PATTERN, TITLE

Description

The CHORO statement specifies the variable or variables that contain the data represented on the map by patterns that fill the map areas. This statement automatically

You can use statement options to enhance the appearance of the map, for example, by selecting the colors and patterns that fill the map areas. Other statement options control the selection of ranges for the response variable.

In addition, you can use global statements to modify the map area patterns and legend, as well as add titles and footnotes to the map. You can also use an Annotate data set to enhance the map.
CHOROresponse-variable(s) </ option(s)>;

option(s) can be one or more options from any or all of the following categories:

Required Arguments

response-variable(s)
specifies one or more variables in the response data set that contains response values that are represented on the map. Each response variable produces a separate map. All variables must be in the input data set. Separate multiple response variables with blanks.

Missing values for the response variable are not considered valid response values unless you use the MISSING option.

Response variables can be either numeric or character. Numeric response variables with continuous values are grouped into ranges, or response levels. Each response level is assigned a different combination of pattern and color. Character variables and numeric variables (when you use the DISCRETE option) have a different response level for each unique response variable value. Numeric variables are treated as continuous unless you use DISCRETE.

For numeric response variables with continuous values, the MIDPOINTS= or LEVELS= option controls the selection of response level ranges.
See also: About Response Variables

Options

Options in a CHORO statement affect all graphs that are produced by that statement. You can specify as many options as you want and list them in any order.

ANNOTATE=Annotate-data-set
ANNO=Annotate-data-set
specifies a data set to annotate maps that are produced by the CHORO statement.
See also: The Annotate Data Set
Featured in: Labeling the States on a U.S. Map

CEMPTY=empty-area-outline-color
outlines empty map areas in the specified color. This option affects the map areas that are empty. Empty map areas are generated in choro maps either

The default outline color is the same as the default COUTLINE= color.
See also: ALL and Displaying Map Areas and Response Data

COUTLINE=nonempty-area-outline-color | SAME
outlines non-empty map areas in the specified color. SAME specifies that the outline color of a map area is the same as the interior pattern color.

The default outline color depends on the PATTERN statement:

Note:   If you specify empty map patterns, (VALUE=MEMPTY in a PATTERN statement) you should not change the outline color from the default value, SAME, to a single color. Otherwise all the outlines will be one color and you will not be able to distinguish between the empty areas.  [cautionend]
Featured in: Producing a Simple Choropleth Map

CTEXT=text-color
specifies a color for the text in the legend. If you omit the CTEXT= option, a color specification is searched for in this order:

  1. the CTEXT= option in a GOPTIONS statement

  2. the default, the first color in the colors list.

The CTEXT= color specification is overridden if you also use the COLOR= suboption of a LABEL= or VALUE= option in a LEGEND definition that is assigned to the map legend. The COLOR= suboption determines the color of the legend label or the color of the legend value descriptions, respectively.

DESCRIPTION='entry-description'
DES='entry-description'
specifies a description of the catalog entry for the map. The maximum length for entry-description is 40 characters. The description does not appear on the map. By default, the GMAP procedure assigns a description of the form CHOROPLETH MAP OF variable, where variable is the name of the map variable.
Featured in: Creating Maps with Drill-down for the Web

DISCRETE
treats a numeric response variable as a discrete variable rather than as a continuous variable. When you use the DISCRETE option, the response variables are not grouped into ranges; instead, the GMAP procedure uses a separate response level (pattern and color combination) for each different value of the formatted response variable. The LEVELS= option is ignored when you use the DISCRETE option.

Use this option if your numeric response variable is assigned a user-written format.

Note:   If the data do not contain a value in a particular range of the format, that formatted range is not displayed in the legend.  [cautionend]
Featured in: Creating Maps with Drill-down for the Web

HTML=variable
identifies the variable in the input data set whose values create links in the HTML file created by the ODS HTML statement. These links are associated with an area of the chart and point to the data or graph you wish to display when the user drills down on the area.
Featured in: Creating Maps with Drill-down for the Web

HTML_LEGEND=variable
identifies the variable in the input data set whose values create links in the HTML file created by the ODS HTML statement. These links are associated with a legend value and point to the data or graph you wish to display when the user drills down on the value.
Featured in: Creating Maps with Drill-down for the Web

LEGEND=LEGEND<1...99>
assigns the specified LEGEND definition to the map legend. LEGEND= is ignored if the specified LEGEND definition is not currently in effect. In the GMAP procedure, the CHORO statement produces a legend unless you use the NOLEGEND option. If you use the SHAPE= option in a LEGEND statement, only the value BAR is valid.
See also: LEGEND Statement
Featured in: Specifying Response Levels in a Block Map

LEVELS=number-of-response-levels
specifies the number of response levels to be graphed when the response variables are continuous. Each level is assigned a different combination of color and fill pattern.

If you do not use the LEVELS= option or the DISCRETE option, the GMAP procedure determines the number of response levels that use the formula FLOOR(1+3.3 log(N)), where N is the number of unique map area identification variable values.

The LEVELS= option is ignored when you use the DISCRETE or MIDPOINTS= option.
Featured in: Specifying Response Levels in a Block Map

MIDPOINTS=value-list
specifies the response levels for the range of response values that are represented by each level (pattern and color combination).

For numeric response variables, value-list is either an explicit list of values, or a starting and an ending value with an interval increment, or a combination of both forms:
n <...n>
n TO n <BY increment >
n <...n> TO n <BY increment > <n <...n> >

By default the increment value is 1. You can specify discrete numeric values in any order. In all forms, n can be separated by blanks or commas. For example, 

midpoints=(2 4 6)
midpoints=(2,4,6)
midpoints=(2 to 10 by 2)

If a numeric variable has an associated format, the specified values must be the unformatted values.

For character response variables, value-list is a list of unique character values enclosed in quotation marks and separated by blanks:
'value-1' <...'value-n'>

The values are character strings enclosed in single quotation marks and separated by blanks. For example, 

midpoints='Midwest' 'Northeast' 'Northwest'

Specify the values in any order. If a character variable has an associated format, the specified values must be the formatted values.

You can selectively exclude some response variable values from the map, as shown here: 

midpoints='Midwest'

Only those observations for which the response variable exactly matches one of the values that are listed in the MIDPOINTS= option are shown on the map. As a result, observations may be excluded inadvertently if values in the list are misspelled or if the case does not match exactly.
Featured in: Specifying Midpoints in a Prism Map

MISSING
accepts a missing value as a valid level for the response variable.
See also: Displaying Map Areas and Response Data

NAME='entry-name'
specifies the name of the catalog entry for the map. The maximum length for entry-name is eight characters. The default name is GMAP. If the specified name duplicates the name of an existing entry, SAS/GRAPH software adds a number to the duplicate name to create a unique entry, for example, GMAP1.
Featured in: Creating Maps with Drill-down for the Web

NOLEGEND
suppresses the legend.
Featured in: Labeling the States on a U.S. Map

XSIZE=map-width <units>
YSIZE=map-height <units>
specify the physical dimensions of the map that is to be drawn, where n is the number of units. By default, the map uses the entire procedure output area.

Valid units are CM (centimeters), IN (inches), or PCT (percentage of the graphics output area). By default, the unit is character cells (CELLS).

If you specify values for n that are greater than the dimensions of the procedure output area, the map is drawn using the default size.

If you specify either the XSIZE= or YSIZE= option without specifying the other option, the GMAP procedure rescales the dimension for the option that was not specified to retain the original shape of the map.


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Copyright 1999 by SAS Institute Inc., Cary, NC, USA. All rights reserved.