SELECT                                                                   SELECT



     The SELECT command is summarized as follows:

          SELECT is a data reclassification command that is used to retrieve
          all, or a specific portion, of a map that is stored in a master or
          work project.  If only a portion of a map is selected, a new map is
          created which contains a subset of the information from the original
          map.  Result of the SELECT command is an active map which is refer-
          enced in the active map table (see ACTIVE).  Maps must be activated
          before they may be analysed or displayed.  SELECT may be thought of
          as the library function that retrieves a book from the stacks and
          checks it out of the library.


     The SELECT command is specified as follows:
     (* denotes parameters which can only be entered in a prompted mode)

          SELECT (map name) (type) (search string)

          or

          SELECT FROM (file 1) (file 2)


     The individual parameters of the SELECT command are described below:

          (map name) is the name of the map to be selected from.

          (type) is the nature of the criterion for data selection.  The user
          may enter ALL, SUbjects, ITems, ATtribute, ELevation, FEatures or
          CUrsor.  The ALL option will activate all items in a map.  Note that
          this is the only method allowed for selection of cell maps.  The
          ELevation option works only on (x,y,z) coordinate data sets.  It
          allows the user to select features based on their elevation.  The
          CUrsor option allows the user to point to items with the cross-
          hair cursor for selection.  The SUbjects, ITems, ATtribute, and
          FEatures options specify that a search string will be used as a
          criterion for selection.  These options require entry of a search
          string as described below.

          (search string) for the SUbjects option is a string of characters
          (e.g., 423PJ or WINTER) that identifies the specific subject or
          combination of subjects, the user wishes to activate.  The characters
          entered are matched against the subjects in the map's subject table.
          Use a plus (+) or a series of +'s as wildcard characters in the
          search so that for instance M+N would match both MAN and MEN.
          There are four variations for subject search.  In the first, the
          entire subject does not have to be entered, only the few characters
          that make it unique.  For example, if you key 'A' this will match
          the subjects LAND and WATER.  In the second variation, you select
          all but the string indicated by using a back slash (\) inserted in
          front of the string.  In the third variation, specify more than one
          string to be matched by entering several separated by an exclamtion
          point (!).  For instance T1!T!T3.  Do not use \ with multiple search
          strings since everything but the \subject is selected anyway.  In the
          final variation, the string entered may be an existing filename
          which contains the subject search string.


          -- For the ITems option, (search string) is a list of up to thirty
          item or feature numbers that are to be selected.  Use of a back slash
          (\) causes all items that do not match the item numbers to be
          selected.  The string entered may also be a filename which contains
          upto thirty item numbers separated by a single space, all as a single
          80 character line.  The back slash (\) may also be used.

          -- For the ATtribute option the user is prompted to select map data
          based on a multiple attribute ID number or KEY.  The map must
          have a multiple attributes file in order to use this option.

          -- For the FEatures option, (search string) is the name of a file
          containing a list of feature numbers to select.  There can be up to
          32,000 feature numbers in this file and they do not have to be in
          sorted order.  Each line of the file must contain a single feature
          number and the last line in the file must be "STOP".

          FROM is a special SELECT option that allows the user to select
          multiple subjects across multiple maps.  (file 1) is a disk file
          created previously, which contains the names of the maps to be se-
          lected from.  This list must be stored one name per line and end
          with the keyword STOP.  Similarly, (file 2) contains the subject
          search strings that the user desires to select with, in the same
          format and endding with the same keyword as (file 1).


     The following are examples of the use of the SELECT command:

           ENTER COMMAND
          ? SELECT
           ENTER NAME OF MAP TO SELECT FROM ? MDRWOLFRG
           ENTER ACTION: ALL,SUBJECTS,ITEM,ATTRIBUTE,ELEVATION,FEATURES ? ALL
               5 HITS FOR ACTIVE ID 1

           ENTER COMMAND
          ? SELECT MDRWOLFRG SUBJECT MDR.SUB.FILE
               3 HITS FOR ACTIVE ID 2
           where MDR.SUB.FILE contains 'MULE DEER WINT C<NL>'


     The limitations of the SELECT command are as follows:

          -- Cannot have more than 40 maps active at any one time.

          -- The total number of features activated can not be more than
             32,000.

          -- Cannot select on the basis of subject from a cell map, i.e., can
             only select ALL from cell maps.

          -- Blanks are not allowed in search strings.  This may cause diffi-
             culties, for example, if the user desires those features labelled
             "1", features labelled "12", "13", and "134" will also be selected.

          -- Items cannot be selected inclusively, e.g., "2 6" will select
             items 2 and 6, not 2 through 6.
