Procedure Syntax

Requirements: The BY and ID statements are required.

PROC GREMOVE < DATA= input-map-data-set >

• • <OUT= output-map-data-set >;

• BY <DESCENDING> variable-l

  • • <...<DESCENDING> variable-n >

    • <NOTSORTED>;

• ID variable(s) ;

PROC GREMOVE Statement

Identifies the input and output map data sets.

Requirements: An input map data set is required.

Syntax

PROC GREMOVE < DATA= input-map-data-set >

• • <OUT= output-map-data-set >;

Options

DATA= input-map-data-set

• specifies the map data set that is to be processed . By default, the procedure uses the most recently created SAS data set. The GREMOVE procedure expects the observations in the input map data set to be sorted in ascending order of the BY-variable values.

• See also: About the Input Map Data Set on page 1224 and SAS Data Sets on page 29.

• Featured in: Example 2 on page 1232.

OUT= output-data-set

• names the new map data set, which contains the coordinates of the new unit areas created by the GREMOVE procedure. By default, the GREMOVE procedure names the new data set using the DATA n naming convention. That is, the procedure uses the name WORK.DATA n , where n is the next unused number in sequence. Thus, the first automatically named data set is DATA1, the second is DATA2, and so on.

• See also: About the Output Map Data Set on page 1225.

• Featured in: Example 2 on page 1232.

BY Statement

Lists the variable or variables that identify the new unit areas.

Requirements: At least one variable is required.

See also: BY Statement on page 141.

Featured in: Example 1 on page 1228.

Syntax

BY <DESCENDING> variable-l

• • <...<DESCENDING> variable-n >

    <NOTSORTED>;

Required Arguments

variable(s)

• identifies one or more variables in the input map data set that define the new unit areas. Variable(s) can be either numeric or character.

  The BY variables in the input map data set become the ID variables for the output map data set.

Options

DESCENDING

• indicates that the input map data set is sorted in descending order. By default, the GREMOVE procedure expects all BY-variable values to appear in ascending order.

  This option affects only the variable that immediately follows the option.

NOTSORTED

• indicates that observations with the same BY-variable values are to be grouped as they are encountered without regard for whether the values are in alphabetical or numerical order. NOTSORTED can appear anywhere in the BY statement. It affects all of the variables that are specified in the statement. NOTSORTED overrides DESCENDING if both appear in the same BY statement.

Ordering Observations

To sort the input map data set, use the SORT procedure in base SAS, for example

 /* arrange the observations in desired order */  proc sort data=mapdata out=mapsort;     by state;  run;     /* remove the county boundaries             */  proc gremove data=mapsort out=newmap;     by state;     id county;  run; 

Notice that the GREMOVE procedure uses the same BY statement as the SORT procedure.

See the Base SAS Procedures Guide for further information on the SORT procedure.

Note: If an observation is encountered for which the BY-variable value is out of the proper order, the GREMOVE procedure stops and issues an error message.

ID Statement

Identifies the variable or variables that define the hierarchy of the current unit areas in the input map data set.

Requirements: At least one id-variable is required.

Featured in: Example 1 on page 1228.

Syntax

ID id-variable(s) ;

Required Arguments

id-variable(s)

• specifies one or more variables in the input map data set that identify the unit areas to be combined. These variables are not included in the output map data set. Id-variable(s) can be either numeric or character.

• See also: About the Input Map Data Set on page 1224.