FREQUENCY                                                             FREQUENCY



     The FREQUENCY command is summarized as follows:

          FREQUENCY is a data description command that produces a table showing
          frequency and percent occurrence of each subject contained on any
          vector map referenced in the active map table.  Specifically,
          FREQUENCY shows the number and frequency of the points, lines, or
          polygons associated with a particular subject on a map.  More than
          one map may be described at the same time.  If the active ID was
          selected using the ATTR option, the frequency will be given in
          terms of the selected attribute.


     The FREQUENCY command is specified as follows:

          FREQUENCY (active ID's) (HARDCOPY) (non-sorted)


     The individual parameters of the FREQUENCY command are described below:

          (active ID's) are the ID numbers of maps referenced in the active map
          table which are to be described.  If more than one map ID is entered
          the command will produce a table describing all of the maps combined
          as one.

          (HARDCOPY) is an option to obtain a hardcopy listing of the FREQUENCY
          table on a line printer.  If HARDCOPY is specified output is written
          to a disk file called LINE.PRINTER.  This file can be printed by
          exiting MOSS and issuing the operating system print command.  If
          anything other than the characters HARDCOPY are specified in this
          option, the characters are used to specify a file name and the output
          is written to the file.  If the file exists, the output is appended to
          the existing file.  The name the operating system uses for the line
          printer can also be specified.  This parameter can only be entered in
          un-prompted mode (see example below).

          (non-sort option) is an option that allows the user to display a
          frequency table for one or more active maps with subjects listed in
          the order digitized.  If the frequency for more than one map is re-
          quested subjects are grouped in the order that the ID's are typed.
          This option is activated by typing an "N" after HARDCOPY, a
          filename or @CONSOLE (to obtain the listing on the screen).
          A default would sort the subjects alphanumerically.


     The following is an example of use of the FREQUENCY command:

           ENTER COMMAND
          ? FREQUENCY
           ENTER ACTIVE MAP I.D.(S)
          ? 1

          To obtain a hardcopy listing:

           ENTER COMMAND
          ? FREQUENCY 1 HARDCOPY

          To obtain a non-sorted hardcopy:

           ENTER COMMAND
          ? FREQUENCY 1 2 HARDCOPY N


     The limitations of the FREQUENCY command are as follows:

          -- No more than 40 active maps may be described at one time.

          -- Input map must be active point, line, or polygon map.

          -- Cannot have more than 2500 total unique subjects in the frequency
             table.

          -- If the LINE.PRINTER file created by the HARDCOPY option is to
             be saved it should be renamed since use of the HARDCOPY option
             deletes existing LINE.PRINTER files.
