                                                                set_union 
Chapter 13 Set and Criteria Selection

The objects in sets s1 and s2 are combined and stored in set s3 with the
set_union command.

set_union

    Performs union of two sets and stores in third.

         set_union s1 s2 s3 [str]

    Performs the union of sets s1 and s2 and stores the resulting objects in
    set s3.  Any data already stored in set s3 will be overwritten.
*   The set created (s3) will be highlighted automatically, and the number of 
*   objects, total length/perimeter in miles, and total area in acres will
*   be displayed on the command line area.
    ___________________________________________________________________________
    Options/arguments:

         s1        Input set
         s2        Input set
         s2        Destination set
         [str]     Set descriptor (user input), optional
    ___________________________________________________________________________
    Example(s):

    To perform a union of cub_1 with cub_2 and store the resulting objects in
    cub_end, enter:

         set_union cub_1 cub_2 cub_end
    ________________________________________________________
    See also:

              set_clear, set_comp, set_exclude, set_intrsec
    ___________________________________________________________________________
