Identifies the input and output map data sets. Can
specify the reduction criteria.

Requirement: | An input map data set is required. |

PROC GREDUCE <option(s)>;

identifies the map data set that you want to process.

specify the minimum distance that a point must lie
from a straight line segment to be included at density level 1, 2,
3, 4, or 5, respectively.

specify that for density level 1, 2, 3, 4, or 5,
the boundary of a unit area should contain no more than max-points points.

disables post-processing cleanup of the output data
set.

names the new map data set, which contains all of
the observations and variables in the original map data set plus the
new DENSITY variable.

- DATA=input-map-data-set
- identifies the map data set that you want to process. By default, the procedure uses the most recently created SAS data set.

- E1=min-distance
- E2=min-distance
- E3=min-distance
- E4=min-distance
- E5=min-distance
- specify the minimum distance that a point must lie from a straight line segment to be included at density level 1, 2, 3, 4, or 5, respectively. That is, in a reduced curve of three points, the middle point is at least a distance that is min-distance from a straight line between the two outside points.

- N1=max-points
- N2=max-points
- N3=max-points
- N4=max-points
- N5=max-points
- specify that for density level 1, 2, 3, 4, or 5,
the boundary of a unit area should contain no more than max-points points. Specify the Nn= values in increasing order. For example, the N2= value should be greater than or equal to the N1= value, and so on.

- NOCLEAN
- disables post-processing cleanup of the output data set. By default, the GREDUCE procedure post-processes the output data set to ensure that at least three vertices are present for each polygon at each density level. If you specify NOCLEAN, then shapes with only one or two points will be included in the output data set.

- OUT=output-data-set
- names the new map data set, which contains all of the observations and variables in the original map data set plus the new DENSITY variable. If the input map data set contains a variable named DENSITY, the GREDUCE procedure replaces the values of the variable in the output map data set. The original values of the DENSITY variable from the input map data set are not included in the output map data set.