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The GCHART Procedure

BLOCK Statement

Creates block charts in which the height of the blocks represents the value of the chart statistic for each category of data.
Requirements: At least one chart variable is required.
Global statements: LEGEND, PATTERN, TITLE, FOOTNOTE
Supports: Drill-down functionality


Description

The BLOCK statement specifies the variable or variables that define the categories of data to chart. This statement automatically does the following actions:

You can use statement options to select or order the midpoints (blocks), to change the type of chart statistic, and to modify the appearance of the chart. You can also specify additional variables by which to group, subgroup, or sum the data.

Block charts enable grouping, which organizes the blocks into rows based on the values of a group variable, and subgrouping, which subdivides the blocks into segments based on the values of a subgroup variable.

In addition, you can use global statements to modify the block patterns and the legend, as well as add titles, footnotes, and notes to the chart. You can also use an Annotate data set to enhance the chart.

Note:   If you get a message that the chart is too large to display on your terminal or printer, try one or both of the following:

  [cautionend]See The Graphics Output and Device Display Areas for details.

Syntax

BLOCK chart-variable(s) </ option(s)>;

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

Required Arguments

chart-variable(s)

specifies one or more variables that define the categories of data to chart. Each chart variable draws a separate chart. All variables must be in the input data set. Separate multiple chart variables with blanks. The values of a chart variable used with the BLOCK statement have a maximum length of 13.

See also: About Chart Variables
Options

Options in a BLOCK statement affect all graphs produced by that statement. You can specify as many options as you want and list them in any order. For details on specifying colors, see SAS/GRAPH Colors and Images. For a complete description of the graphics options, see Graphics Options and Device Parameters Dictionary.

ANNOTATE=Annotate-data-set

specifies a data set to annotate charts produced by the BLOCK statement.

Note:   Annotate coordinate systems 1, 2, 7, and 8 (data system coordinates) are not valid with block charts.  [cautionend]

Alias: ANNO=
See also: Using Annotate Data Sets
BLOCKMAX=max-value

specifies the chart statistic value of the tallest block on the chart. This option lets you produce a series of block charts using the same scale. All blocks are rescaled as if max-value were the maximum value on the chart.

Restriction: Not supported by Java or ActiveX
CAXIS=grid-color

specifies the color for the midpoint grid. By default, the midpoint grid uses the color of the current style, or, if the NOGSTYLE option is specified, then the default color is black for the Java and ActiveX devices and the first color in the color list for all other devices.

Style reference: Color attribute of the GraphAxisLines element.
Featured in: Grouping and Subgrouping a Block Chart
COUTLINE=block-outline-color | SAME

outlines all blocks or all block segments and legend values in the subgroup legend (if it appears) using the specified color. SAME specifies that the outline color of a block or a block segment or a legend value is the same as the interior pattern color.

The default outline color depends on the PATTERN statement:

  • If you do not specify a PATTERN statement, the default outline color is the color of the current style.

  • If you specify the NOGSTYLE option and no PATTERN statement, the default outline color is black for the Java or ActiveX devices. Otherwise, the default outline color is the foreground color. If you specify an EMPTY PATTERN statement, then the default outline color is the same as the fill color.

Style reference: Color attribute of the GraphOutlines element.
Featured in: Grouping and Subgrouping a Block Chart
Restriction: Partially supported by Java and ActiveX
See also: Controlling Block Chart Patterns and Colors and About Patterns
CTEXT=text-color

specifies a color for all text on the axes and legend, including axis labels, tick mark values, legend labels, and legend value descriptions. The GCHART procedure looks for the text color in the following order:

  1. colors specified for labels and values on assigned AXIS and LEGEND statements, which override the CTEXT= option specified in the BLOCK statement

  2. the color specified by the CTEXT= option in the BLOCK statement

  3. the color specified by the CTEXT= option in a GOPTIONS statement.

  4. the color specified in the current style or, if the NOGSTYLE option is specified, then the default color is black for the Java and ActiveX devices and the first color in the color list for all other devices

The LEGEND statement's VALUE= color is used for legend values, and its LABEL= color is used for legend labels.

The AXIS statement's VALUE= color is used for axis values, and its LABEL= color is used for axis labels. However, if the AXIS statement specifies only general axis colors with its COLOR= option, the CTEXT= color overrides the general COLOR= specification and is used for axis labels and values; the COLOR= color is still used for all other axis colors, such as tick marks.

Note:   If you use a BY statement in the procedure, the color of the BY variable labels is controlled by the CBY= option in the GOPTIONS statement.  [cautionend]

Style reference: Color attributes of the GraphValueText and the GraphLabelText elements.
DESCRIPTION='description'

specifies the description of the catalog entry for the chart. The maximum length for entry-description is 256 characters. The description does not appear on the chart. By default, the GCHART procedure assigns a description of the form BLOCK CHART OF variable, where variable is the name of the chart variable.

The entry-description can include the #BYLINE, #BYVAL, and #BYVAR substitution options, which work as they do when used on TITLE, FOOTNOTE, and NOTE statements. Refer to Substituting BY Line Values in a Text String. The 256-character limit applies before the substitution takes place for these options; thus, if, in the SAS program, the entry-description text exceeds 256 characters, it is truncated to 256 characters, and then the substitution is performed.

The descriptive text is shown in each of the following:

  • the "description" portion of the Results window.

  • the catalog-entry properties that you can view from the Explorer window.

  • the Description field of the PROC GREPLAY window.

  • the data tip text for Web output (depending on the device driver you are using). See Data Tips for Web Presentations for details.

Alias: DES=
DISCRETE

treats a numeric chart variable as a discrete variable rather than as a continuous variable. The GCHART procedure creates a separate midpoint and, hence, a separate grid square and block for each unique value of the chart variable. If the chart variable has a format associated with it, then each formatted value is treated as a midpoint.

The LEVELS= option is ignored when you use DISCRETE. The MIDPOINTS= option overrides DISCRETE.

FREQ=numeric-variable

specifies a variable whose values weight the contribution of each observation in the computation of the chart statistic. Each observation is counted the number of times specified by the value of numeric-variable for that observation. If the value of numeric-variable is missing, 0, or negative, the observation is not used in the statistic calculation. Non-integer values of numeric-variable are truncated to integers.

FREQ= is valid with all chart statistics.

Because you cannot use the PERCENT, CPERCENT, FREQ, or CFREQ statistics with the SUMVAR= option, you must use the FREQ= option to calculate percentages, cumulative percentages, frequencies, or cumulative frequencies based on a sum.

The statistics are not affected by applying a format to numeric-variable.

See also: Calculating Weighted Statistics
GAXIS=AXIS<1...99>

assigns the specified AXIS definition to the group axis. (A group axis is created when you use the GROUP= option.) You can use the AXIS definition to modify the order of the groups, the text of the labels, and appearance of the axis. GAXIS= is ignored if the specified AXIS definition does not exist.

The AXIS statement options MAJOR= and MINOR= are ignored in AXIS definitions assigned to the group axis because the axis does not use tick marks. A warning message is written to the SAS log if these options appear in the AXIS definition.

The Java and ActiveX devices do not support all AXIS statement options. See AXIS Statement for more information.

To remove groups from the chart, use the ORDER= option in the AXIS statement.

To suppress the brackets drawn around the values on the group axis in vertical bar charts, use the NOBRACKETS option in the AXIS statement.

Featured in: Example: Creating Bar Charts with Drill-Down for the Web
Restriction: Supported by Java and ActiveX only.
See also: AXIS Statement
G100

calculates the percentage and cumulative percentage statistics separately for each group. When you use G100, the individual percentages reflect the contribution of the midpoint to the group and total 100 percent for each group. G100 is ignored unless you also use the GROUP= option.

By default, the individual percentages reflect the contribution of the midpoint to the entire chart and total 100 percent for the entire chart.

GROUP=group-variable

organizes the data according to the values of group-variable. Group-variable can be either character or numeric and is always treated as a discrete variable. The group variable can have up to 12 different values.

GROUP= produces a group grid that contains a separate row of blocks for each unique value of the group variable. Each row contains a square for each midpoint. The groups are arranged from front to back in ascending order of the group variable values. These values are printed to the left of each row; the group variable name or label is printed above the list of group values.

By default, each group includes all midpoints, even if no observations for the group fall within the midpoint range. Missing values for group-variable are treated as a valid group.

Featured in: Grouping and Subgrouping a Block Chart
HTML=variable

identifies the variable in the input data set whose values create links in the HTML file that is created by the ODS statement. These links are associated with an area of the chart and point to the data or graph you want to display when the user drills down on the area. There is no limit on the length of the variable.

See also: Overview of Enhancing Web Presentations
HTML_LEGEND=variable

identifies the variable in the input data set whose values create links in the HTML file that is created by the ODS statement. These links are associated with a legend value and point to the data or graph that you want to display when the user drills down on the value. The values of variable can be up to 1024 characters long. Characters after the 1024-character limit (including any closing quotes) are truncated.

Restriction: Not supported by Java orActiveX
See also: Overview of Enhancing Web Presentations
LEGEND=LEGEND<1...99>

assigns the specified LEGEND definition to the legend generated by the SUBGROUP= option. The LEGEND= option itself does not generate a legend.

LEGEND= is ignored if the following is true:

  • SUBGROUP= is not used.

  • The specified LEGEND definition is not in effect.

  • The NOLEGEND option is used.

  • The PATTERNID= option is set to any value other than SUBGROUP; that is, the value of PATTERNID= is BY or GROUP or MIDPOINT.

To create a legend based on the chart midpoints instead of the subgroups, use the chart variable as the subgroup variable: 

block city / subgroup=city;

The Java and ActiveX devices do not support all LEGEND statement options. See LEGEND Statement for more information.

Featured in: Grouping and Subgrouping a Block Chart
Restriction: Partially supported by Java and ActiveX
See also: SUBGROUP= and LEGEND Statement
LEVELS=number-of-midpoints

specifies the number of midpoints for the numeric chart variable. The range for each midpoint is calculated automatically using the algorithm described in Terrell and Scott (1985). The LEVELS= option is ignored if the following is true:

  • The chart variable is character type.

  • The DISCRETE option is used.

  • The MIDPOINTS= option is used.

MAXIS=AXIS<1...99>

assigns the specified AXIS definition to the midpoint axis. The MAXIS= option is ignored if the specified AXIS definition does not exist.

The Java and ActiveX devices do not support all AXIS statement options. See AXIS Statement for more information.

Featured in: Subgrouping a Three-Dimensional Vertical Bar Chart
Restriction: Supported by Java and ActiveX only
See also: AXIS Statement and About Midpoints
MIDPOINTS=value-list

specifies the midpoint values for the blocks. The way you specify value-list depends on the type of variable:

  • For numeric chart 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>>

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

    If you omit the DISCRETE option, then numeric values are treated as continuous, which means that the following is true by default:

    • The lowest midpoint consolidates all data points from negative infinity to the median of the first two midpoints.

    • The highest midpoint consolidates all data points from the median of the last two midpoints up to infinity.

    • All other values in value-list specify the median of a range of values, and the GCHART procedure calculates the midpoint values.

    If you include the DISCRETE option, then each value in value-list specifies a unique numeric value.

  • For character chart variables, value-list is a list of unique character values enclosed in quotation marks and separated by blanks:

    'value-1' <...'value-n'>

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

For a complete description of value-list, see the ORDER= option in the AXIS statement.

If value-list for either type of variable specifies so many midpoints that the axis values overwrite each other, then the values might be unreadable. In this case the procedure writes a warning to the SAS log. On many devices, you can correct crowded values by increasing the number of cells in your graphics display using the HPOS= and VPOS= graphics options.

Featured in: Grouping and Subgrouping a Block Chart
See also: About Midpoints
MIDPOINTS=OLD

generates default midpoints using the Nelder algorithm (Applied Statistics 25:94-7, 1976). The MIDPOINTS=OLD option is ignored unless the chart variable is numeric.

MISSING

accepts a missing value as a valid midpoint for the chart variable. By default, observations with missing values are ignored. Missing values are always valid for the group and subgroup variables.

NAME='entry-name'

specifies the name of the GRSEG catalog entry and the name of the graphics output file, if one is created. The name can be up to 256 characters long, but the GRSEG name is truncated to eight characters. Uppercase characters are converted to lowercase, and periods are converted to underscores. The default name is GCHART. If the name duplicates an existing name, then SAS/GRAPH adds a number to the name to create a unique name--for example, GCHART1.

See also: About Filename Indexing
NOHEADING

suppresses the heading describing the type of statistic. For the Java and ActiveX devices, NOHEADING is the default. For other devices, by default the heading is printed at the top of each block chart.

Featured in: Grouping and Subgrouping a Block Chart
Restriction: Not supported by Java or ActiveX
NOLEGEND

suppresses the legend automatically generated by the SUBGROUP= option. NOLEGEND is ignored if the SUBGROUP= option is not used.

PATTERNID=BY | GROUP | MIDPOINT | SUBGROUP

specifies the way fill patterns are assigned. By default, PATTERNID=SUBGROUP. Values for PATTERNID= are as follows:

BY

changes patterns each time the value of the BY variable changes. All blocks use the same pattern if the GCHART procedure does not include a BY statement.

GROUP

changes patterns every time the value of the group variable changes. All blocks in each group (row) use the same pattern, but a different pattern is used for each group.

MIDPOINT

changes patterns every time the midpoint value changes. If you use the GROUP= option, the respective midpoint patterns are repeated for each group.

SUBGROUP

changes patterns every time the value of the subgroup variable changes. The blocks must be subdivided by the SUBGROUP= option for the SUBGROUP value to have an effect. Without SUBGROUP=, all block faces have the same pattern.

Note:   If you use the SUBGROUP= option and specify a PATTERNID= value other than SUBGROUP, the block segments use the same pattern and are indistinguishable.  [cautionend]

Featured in: Example: Creating Bar Charts with Drill-Down for the Web
See also: Controlling Block Chart Patterns and Colors
RAXIS=value-list | AXIS<1...99>
AXIS=value-list | AXIS<1...99>

specifies values for the major tick mark divisions on the response axis or assigns the specified AXIS definition to the axis. See the MIDPOINTS= option for a description of value-list. By default, the GCHART procedure scales the response axis automatically and provides an appropriate number of tick marks.

You can specify negative values, but negative values are reasonable only when TYPE=SUM or TYPE=MEAN and one or more of the sums or means are less than 0. Frequency and percentage values are never less than 0.

For lists of values, a separate major tick mark is created for each individual value. A warning message is written to the SAS log if the values are not evenly spaced.

If the values represented by the bars are larger than the highest tick mark value, the bars are truncated at the highest tick mark.

If you use a BY statement with the PROC GCHART statement, then the same response axes are produced for each BY group when RAXIS=value-list is used or if there is an ORDER= list in the AXIS statement assigned to the response axis.

The Java and ActiveX devices do not support all AXIS statement options. See AXIS Statement for more information.

Featured in: Subgrouping a Three-Dimensional Vertical Bar Chart and Example: Creating Bar Charts with Drill-Down for the Web
Restriction: Supported by Java and ActiveX only
See also: AXIS Statement
SUBGROUP=subgroup-variable

divides the blocks into segments according to the values of subgroup-variable. Subgroup-variable can be either character or numeric and is always treated as a discrete variable. SUBGROUP= creates a separate segment within each block for every unique value of the subgroup variable for that midpoint.

If PATTERNID=SUBGROUP (the default setting), each segment is filled with a different pattern, and a legend providing a key to the patterns is automatically generated. If the value of PATTERNID= is anything other than SUBGROUP, the segments are all the same color, the legend is suppressed, and the subgrouping effect is lost.

By default the legend appears at the bottom of the chart. To modify the legend, assign a LEGEND definition with the LEGEND= option. To suppress the legend, specify NOLEGEND.

Featured in: Grouping and Subgrouping a Block Chart
See also: LEGEND Statement
SUMVAR=summary-variable

specifies a numeric variable for sum or mean calculations. The GCHART procedure calculates the sum or, if requested, the mean of numeric-variable for each midpoint. The resulting statistics are represented by the height of the blocks in each square. The values of a summary variable used with the BLOCK statement have a maximum length of 8.

When you use SUMVAR=, the TYPE= option value must be either SUM or MEAN. With SUMVAR=, the default is TYPE=SUM.

Featured in: Specifying the Sum Statistic in a Block Chart
TYPE=statistic

specifies the chart statistic.

  • If the SUMVAR= option is not used, statistic can be one of the following:

    FREQ

    frequency (the default)

    CFREQ

    cumulative frequency

    PERCENT PCT

    percentage

    CPERCENT CPCT

    cumulative percentage

  • If SUMVAR= is used, statistic can be either:

    SUM

    sum (the default)

    MEAN

    mean

Because you cannot specify the statistics PERCENT, CPERCENT, FREQ, or CFREQ in conjunction with the SUMVAR= option, you must use FREQ= to calculate percentages, cumulative percentages, frequencies, or cumulative frequencies based on a sum. See also Calculating Weighted Statistics.

If you specify TYPE=MEAN and use the SUBGROUP= option, the height of the block represents the mean for the entire midpoint. The subgroup segments are proportional to the subgroup's contribution to the sum for the block.

Featured in: Grouping and Subgrouping a Block Chart
See also: About Chart Statistics
WOUTLINE=block-outline-width

specifies the width of the block outline in pixels.

Style reference: LineThickness attribute of the GraphOutlines element.
Restriction: Not supported by Java
Controlling Block Chart Patterns and Colors


Default patterns and outlines

Each block in a block chart is filled with a pattern, but only the front faces of the blocks display the patterns. Because the system option, GSTYLE, is in effect by default, the procedure uses the style's default patterns and outlines when producing output. By default, the procedure does the following:

See About Patterns for more information on how the GCHART procedure assigns default patterns and outlines.


User-defined patterns

To override the default patterns and select fills and colors for the blocks or block segments, use the PATTERN statement. Only bar or block patterns are valid; all other pattern fills are ignored. For a complete description of all bar or block patterns, see the description of the PATTERN statement option VALUE=.

Whenever you use PATTERN statements, the default pattern outline color is that of the current style. Only when the EMPTY pattern is used does the pattern change to SAME. That is, the outline color is the same as the fill color. To specify the outline color, use the COUTLINE= option.


When patterns change

The PATTERNID= option controls when the pattern changes. By default, PATTERNID=SUBGROUP. Therefore, when you use the SUBGROUP= option to subdivide the blocks, the pattern automatically changes each time the subgroup value changes, and each subdivision of the block displays a different pattern. As a result, the number of values for the SUBGROUP= variable determines the number of block patterns on the chart. If you do not subdivide the blocks, all blocks use the same pattern.

Instead of changing the pattern for each subgroup, you can change the pattern for each midpoint, each group, or each BY group, by changing the value of the PATTERNID= option. See the PATTERNID= option for details.


Axis color

By default, axis elements use the color specified in the current style. To change the grid color, use the CAXIS= option. To change the axis text color, use the CTEXT= option.

Controlling Block Chart Text

To control the font and size of text on the chart, use the FTEXT= and HTEXT= graphics options. See Graphics Options and Device Parameters Dictionary for a description of these options.

Because block charts do not use AXIS statements, you must use a LABEL statement instead to suppress the label for the midpoint variable. See Grouping and Subgrouping a Block Chart.

Displaying Negative or Zero Values

The relative block heights in the chart represent the scaled value of the chart statistic value for the midpoint. If the statistic has a value of 0 or, in the case of sum and mean, a negative value, the base of the block is drawn in the square for the corresponding midpoint. Block Chart with 0 and Negative Statistic Values shows an example of a chart with 0 and negative statistic values.

Block Chart with 0 and Negative Statistic Values

[Block Chart with 0 and Negative Statistic Values]

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