GREDUCE Procedure

About the Input Map Data Set

The input map data set must be a SAS data set and contain these variables:
  • a numeric variable named X that contains the horizontal coordinates of the map boundary points.
  • a numeric variable named Y that contains the vertical coordinates of the map boundary points.
  • one or more identification variables that uniquely identify the unit areas in the map. These variables are listed in the ID statement.
It can also contain the following:
  • one or more variables that identify groups of unit areas (for BY-group processing)
  • the variable SEGMENT, which distinguishes nonconterminous segments of the unit areas.
Any other variables in the input map data set do not affect the GREDUCE procedure.