













                                 PLOT PLUS
                        Scientific Graphics System

                                    by

                              Donald W. Denbo



                             Vax Version 0.87
                               April 8, 1987






                                          CONTENTS



       CHAPTER 1       INTRODUCTION


       CHAPTER 2       GETTING STARTED

               2.1      VAX/VMS   . . . . . . . . . . . . . . . . . . . . 2-1
               2.1.1     To Get A Copy Of This Manual . . . . . . . . . . 2-1
               2.1.2     Required Definitions . . . . . . . . . . . . . . 2-1
               2.1.3     Optional Definitions . . . . . . . . . . . . . . 2-2


       CHAPTER 3       COMMAND FORMAT


       CHAPTER 4       COMMAND SYNOPSIS

               4.1      FILES   . . . . . . . . . . . . . . . . . . . . . 4-1
               4.1.1     Data Files . . . . . . . . . . . . . . . . . . . 4-1
               4.1.2     Other Data Entry . . . . . . . . . . . . . . . . 4-1
               4.1.3     PPLUS Output Files . . . . . . . . . . . . . . . 4-2
               4.1.4     PPLUS Command Files  . . . . . . . . . . . . . . 4-2
               4.2      AXIS  . . . . . . . . . . . . . . . . . . . . . . 4-2
               4.2.1     X- And Y-axis  . . . . . . . . . . . . . . . . . 4-2
               4.2.2     Time Axis  . . . . . . . . . . . . . . . . . . . 4-2
               4.3      LABELS  . . . . . . . . . . . . . . . . . . . . . 4-3
               4.4      COMMAND PROCEDURES  . . . . . . . . . . . . . . . 4-3
               4.5      COLOR AND FONTS   . . . . . . . . . . . . . . . . 4-3
               4.6      PLOT GENERATION   . . . . . . . . . . . . . . . . 4-4
               4.7      DATA MANIPULATION   . . . . . . . . . . . . . . . 4-4
               4.8      HELP  . . . . . . . . . . . . . . . . . . . . . . 4-4


       CHAPTER 5       BEGINNERS GUIDE

               5.1      FORMAT  . . . . . . . . . . . . . . . . . . . . . 5-1
               5.2      VARS  . . . . . . . . . . . . . . . . . . . . . . 5-1
               5.3      SKP  AND  RD  . . . . . . . . . . . . . . . . . . 5-3
               5.4      PLOT  AND  CONTOUR  . . . . . . . . . . . . . . . 5-4
               5.5      EXAMPLES  . . . . . . . . . . . . . . . . . . . . 5-4
               5.5.1     Unformatted Data, X-Y Plot . . . . . . . . . . . 5-4
               5.5.2     Pre-gridded Data, Contour Plot . . . . . . . . . 5-4
               5.5.3     Ungridded Data, Contour Plot . . . . . . . . . . 5-5
               5.5.4     Time Series Plot . . . . . . . . . . . . . . . . 5-6


       CHAPTER 6       ROUTING PLOT FILES

               6.1      VAX/VMS   . . . . . . . . . . . . . . . . . . . . 6-1
               6.1.1     Plot Files And Mom . . . . . . . . . . . . . . . 6-1
               6.1.2     Plotting Devices . . . . . . . . . . . . . . . . 6-2
               6.1.3     Examples . . . . . . . . . . . . . . . . . . . . 6-2



                                                                       Page 2


       CHAPTER 7       PPLUS COMMAND FILES

               7.1      INTRODUCTION  . . . . . . . . . . . . . . . . . . 7-1
               7.2      SYMBOL SUBSTITUTION   . . . . . . . . . . . . . . 7-1
               7.3      GENERAL GLOBAL SYMBOLS  . . . . . . . . . . . . . 7-3
               7.4      EPIC GLOBAL SYMBOLS   . . . . . . . . . . . . . . 7-4
               7.5      COMMAND FILE LOGIC  . . . . . . . . . . . . . . . 7-5
               7.6      ARITHMETIC  . . . . . . . . . . . . . . . . . . . 7-6
               7.7      SYMBOL ARRAYS   . . . . . . . . . . . . . . . . . 7-6
               7.8      SPECIAL FUNCTIONS . . . . . . . . . . . . . . . . 7-7
               7.8.1     $EDIT  . . . . . . . . . . . . . . . . . . . . . 7-8
               7.8.2     $EXTRACT   . . . . . . . . . . . . . . . . . . . 7-8
               7.8.3     $INTEGER   . . . . . . . . . . . . . . . . . . . 7-9
               7.8.4     $LENGTH  . . . . . . . . . . . . . . . . . . . . 7-9
               7.8.5     $LOCATE  . . . . . . . . . . . . . . . . . . .  7-10
               7.8.6     $ELEMENT   . . . . . . . . . . . . . . . . . .  7-10


       CHAPTER 8       LABELS

               8.1      AXIS LABELING   . . . . . . . . . . . . . . . . . 8-1
               8.2      EMBEDDED STRING COMMANDS  . . . . . . . . . . . . 8-1
               8.2.1      Fonts   . . . . . . . . . . . . . . . . . . . . 8-2
               8.2.2      Pen Selection   . . . . . . . . . . . . . . . . 8-3
               8.2.3      Character Slant   . . . . . . . . . . . . . . . 8-3
               8.2.4      Subscripting, Superscripting And Back Spacing   8-3


       CHAPTER 9       DATA FORMATS

               9.1      SEQUENTIAL FORMATS    . . . . . . . . . . . . . . 9-1
               9.2      BIBO FORMAT   . . . . . . . . . . . . . . . . . . 9-2
               9.3      EPIC FORMAT   . . . . . . . . . . . . . . . . . . 9-2
               9.4      DSF FORMAT    . . . . . . . . . . . . . . . . . . 9-2
               9.4.1      ITYPE=0   . . . . . . . . . . . . . . . . . . . 9-3
               9.4.2      ITYPE=1   . . . . . . . . . . . . . . . . . . . 9-3


       CHAPTER 10      ADVANCED COMMANDS


       CHAPTER 11      PLOT5, PPLUS DIFFERENCES


       CHAPTER 12      COMMAND DESCRIPTION
















                                 CHAPTER 1

                               INTRODUCTION



               Plot  Plus  (PPLUS)  is   an   interactive,   command-driven
          general-purpose  program  for plotting user supplied data.  PPLUS
          recognizes data in standard fortran  formatted,  unformatted  and
          free  format  files  as well as some specialized formats (see the
          chapter on Data Formats).  Data can  also  be  entered  from  the
          keyboard.

               The major use of PPLUS is the plotting of contour  data  and
          X-Y  pairs.   A  very  small  number  of commands are required to
          generate a plot, making  use  of  the  many  defaults  available.
          However,  it  is  also possible to control almost every aspect of
          the plot and to generate a final product which looks as though it
          were  professionally  drafted.   Over  thirty  character sets are
          available, including special  Greek  and  Math  symbols.   It  is
          possible  to make a composite of several plots of different kinds
          (or the same kind) on a single page and to add  text  information
          anywhere on the plot.

               PPLUS  commands  can  be  entered  interactively  from   the
          keyboard or from a command file much like a VAX/VMS command file.
          PPLUS   command   files   support   parameter   passing,   symbol
          substitution,  and logic structures such as WHILE loops and block
          IF statements.  The PPLUS command files  are  simple  ASCII  disk
          files which are easily edited with any VAX/VMS editor.

               Interactive help is available with the VAX/VMS command  HELP
          PPLUS.   (First,  PPLUS definitions must have been established as
          indicated in the Getting Started chapter.)














                                 CHAPTER 2

                              GETTING STARTED




          2.1  VAX/VMS

          2.1.1  To Get A Copy Of This Manual

               To get a copy of this manual, type the  following  lines  on
          your terminal in response to the VAX/VMS prompt:

          $ @DISK1:[OC.SYMBOLS]PLOT5
          $ PPLUS_MANUAL
          $ PPLUS_FONTS

          The manual will be printed on the laser printer,  and  the  PPLUS
          character fonts will be plotted on the Versatec plotter.



          2.1.2  Required Definitions

               PPLUS  requires  several  assignments  and  definitions   to
          execute  under  VMS.   The  following  should be included in your
          LOGIN.COM file prior to running PPLUS:

          $ @DISK1:[OC.SYMBOLS]PLOT5.COM
          $ GRAPHTERM :== xxxx,

          where xxxx describes your graphics terminal and has the following
          allowed values:

            VT240
            GVT+
            ZENITH
            TEK4010
            MAC
            TEK41XX
            TEK4105 
            TAB.  



GETTING STARTED                                                    Page 2-2


          In order to provide automatic entry and  exit  into  and  out  of
          graphics  mode  you  should use the GRAPHTERM that corresponds to
          your  terminal.   If  your  terminal  is  a  TEK4010  or  TEK4014
          compatible,  but  not  one of the above, then place your terminal
          into graphics mode before plotting and use GRAPHTERM :== TEK4010.
          The  execution  of PLOT5.COM will define any other symbols needed
          by PPLUS.

               PPLUS is entered interactively by typing PPLUS (or just PPL)
          in response to the VAX/VMS prompt.

               Interactive help  is  available  by  typing  HELP  PPLUS  in
          response  to  the  VAX/VMS  prompt.  If you are in PPLUS, help is
          available by typing HLP.



          2.1.3  Optional Definitions

               In addition to the above, the following VAX/VMS symbols  and
          logicals may optionally be defined by the user:

            PPL$RESET       The "SAVE" file to be used by the PPLUS RESET
                            command (logical).  Default is 
                            PPL$EXE:PPL$RESET.DAT

            ECHO            Defines the file to be used to echo PPLUS 
                            commands (logical). Default is ECHO.DAT.

            PPL$STARTUP     Defines an initialization or startup command
                            command file that will be executed each time 
                            PPLUS is entered (symbol).  Default is no
                            startup command file.

            Example definitions:

                  DEFINE PPL$RESET DISK1:[your-directory]your-reset.file
                  DEFINE ECHO your-echo.file
                  PPL$STARTUP :== DISK1:[your-directory]your-startup.file














                                 CHAPTER 3

                              COMMAND FORMAT




          THE COMMANDS

               The basic format for PPLUS commands is:

                COMM[/Q1/Q2 ... ][,arg1,arg2,arg3...][,sarg1,sarg2...]

          where  COMM  is  the  PPL   command.    The   numeric   arguments
          arg1,arg2,...  may be numbers in any fortran format (e.g.  1.E-5,
          -6,  10.23)   or   blank.    The   character   string   arguments
          sarg1,sarg2,...   must  begin with a non-numeric character string
          or be enclosed in quotes ("), i.e., "100".   If  the  numeric  or
          character  string  arguments  are  blank, the input is considered
          null and the default is used.  Where all numeric arguments are to
          be  defaulted,  they may be omitted entirely (i.e., blank entries
          need not be made).

               PPLUS commands may have optional qualifiers (Q1, Q2 etc...).
          The  format  for qualifiers is "/value" or "/novalue" for true or
          false, respectively.

               All parameters must be separated by commas or blanks, except
          null entries which must have separating commas.  Null entries are
          allowed except where noted in the specific command description.

               Commands can be continued on sequential lines by inserting a
          "-" (minus sign) at the end of the line to be continued.

               All commands/parameters may be entered upper or lower  case.
          Conversion   to   upper  case  is  performed  automatically  when
          required.














                                 CHAPTER 4

                             COMMAND SYNOPSIS



               This is intended as a brief overview of the PPLUS  commands.
          Commands  are fully described in the Command Description chapter.
          Examples illustrating  their  use  are  in  the  Beginners  Guide
          chapter and in the Appendix.




          4.1  FILES

          4.1.1  Data Files

               These commands are used to extract the  information  from  a
          file containing the data to be plotted.

          RD      Reads/identifies file containing data to be plotted.
          SKP     Skips/identifies records on the data file being read.
          RWD     Rewinds/identifies the data file.
          FORMAT  Describes the format of the data file.
          VARS    Locates the data to be plotted in the records of the data
                  file.
          EVAR    Locates the data to be plotted in the records of the EPIC
                  data file.
          AUTOLAB Controls automatic labeling of EPIC and BIBO data plots.



          4.1.2  Other Data Entry

               The following commands allow data entry from a  souce  other
          than a file.

          ENTER   Allows data entry from the keyboard.
          LINFIT  Does a linear least squares fit on data already in a line
                  and inserts the least squares line into the next
          available
                  line.



COMMAND SYNOPSIS                                                   Page 4-2


          4.1.3  PPLUS Output Files

          ECHO    Controls echoing of PPLUS commands to a PPLUS echo file.
          DEBUG   Controls PPLUS debug mode (echos after symbol 
                  substitution)
          PLTNME  Names the output plot file.
          PLTYPE  Controls the format of the output plot file.



          4.1.4  PPLUS Command Files

          @       Initiates reading of commands from a PPLUS command file.
          ECHO    Controls echoing of PPLUS commands to a PPLUS echo file.
          DEBUG   Controls PPLUS debug mode (echos after symbol 
                  substitution)



          4.2  AXIS

               The  following   commands   control   axis   labelling   and
          appearance.



          4.2.1  X- And Y-axis

          XAXIS   Controls numeric labeling and tics on the x-axis.
          YAXIS   Controls numeric labeling and tics on the y-axis.
          AXATIC  Sets number of large tics automatically for x and y.
          AXLABP  Locates axis labels at top/bottom or left/right of plot.
          AXLEN   Sets axis lengths.
          AXLINT  Sets label interval for axes.
          AXLSZE  Sets axis label heights.
          AXNMTC  Sets number of small tics between large tics on axes.
          AXNSIG  Sets no. significant digits in numeric axis labels (auto 
                  only).
          AXSET   Allows omission of plotting of any axis.
          AXTYPE  Sets axis type for x- and y-axis.
          TICS    Sets axis tic characteristics
          XFOR    Sets format of x-axis numeric labels.
          YFOR    Sets format of y-axis numeric labels.
          XLAB    Sets label of x-axis.
          YLAB    Sets label of y-axis.



          4.2.2  Time Axis

          TIME    Sets start and end of time axis, start time of data.
          TAXIS   Sets time axis on, sets time series delta-t (minutes), 
                  orients axis.



COMMAND SYNOPSIS                                                   Page 4-3


          TXLABP  Establishes time axis label position (or absence).
          TXLINT  Specifies which tics will be labeled.
          TXLSZE  Sets height of time axis labels.
          TXNMTC  Sets number of small tics between large tics.
          TXTYPE  Sets type and style of time axis.



          4.3  LABELS

          LABS    Makes a moveable label (up to 25 labels allowed).
          HLABS   Sets height of each moveable label.
          RLABS   Sets angle for each moveable label.
          LABSET  Sets character heights for labels.
          LLABS   Sets start position for a line to location of each 
                  moveable label.  Draws a line from the label to a
                  point.
          CONPRE  Sets prefix for contour labels (characters, color, font).
          CONPST  Set suffix for contour labels (characters, color, font).
          TITLE   Sets and clears main plot label (without making a plot).
          XLAB    Sets label of x-axis.
          YLAB    Sets label of y-axis.



          4.4  COMMAND PROCEDURES

          @       Initiates reading of commands from a PPLUS command file.
          DEC     Decrements a counter.
          INC     Increments a counter.
          IF      Block IF statement.
          ELSE    Block IF statement.
          ENDIF   Block IF statement.
          WHILE   WHILE loop construct.
          ENDW    WHILE loop construct.
          SET     Sets the value of a PPLUS symbol.
          SHOW    Shows the value of a PPLUS symbol.
          LISTSYM Lists values of defined PPLUS symbols.



          4.5  COLOR AND FONTS

               Commands to change the pen number or the character font  can
          be  embedded  in  any labels character string.  See the preceding
          section for label commands and the chapter on LABELS.

          @Pn     Sets pen number "n" when embedded in a label.
          @Cnnn   Sets color to number "nnn" when embedded in a label.
          PEN     Sets pen number for each data line.
          DFLTFNT Sets default character font for all labeling.
          LEV     Sets pen numbers (colors) for contour plots.

           PLOT APPEARANCE 



COMMAND SYNOPSIS                                                   Page 4-4


           The following commands control various aspects of the plot's
          appearance.

          ORIGIN  Sets distance of plot origin from lower left corner of 
                  the box.
          SIZE    Sets size of entire plotting region.
          BOX     Controls drawing of a box around the entire plotting 
                  region.
          CROSS   Controls drawing of lines through the point x=0, y=0 on 
                  graph.
          LINE    Sets characteristics for each X-Y plot line.
          MARKH   Sets character size for each X-Y plot line marks.
          MULTPLT Allows a composite of several plots (all kinds) on one 
                  page.
          ROTATE  Rotates plot by 90 degrees on screen and plotter.



          4.6  PLOT GENERATION

               The following commands select the plot type and generate the
          plot.

          PLOT    Plots x-y pairs for all lines of data.
          PLOTUV  Makes stick plot of vector data for U,V pairs in line1.
          PLOTV   Makes stick plot of vector data for U in line1 and V in 
                  line2.
          CONTOUR Makes contour plot.
          VIEW    Makes a 3-D surface plot.
          VPOINT  Sets the viewpoint for a 3-D surface plot.
          VECTOR  Makes a plot of a vector field
          VELVCT  Makes vector plot of U,V pairs located at X,Y locations.
          MULTPLT Allows a composite of several plots (all kinds) on one 
                  page.



          4.7  DATA MANIPULATION

          LINFIT  Does a linear least squares fit on data already in a line
                  and inserts the least squares line into the next 
                  available line.
          TRANSXY Applies a linear transformation to variables x and y.
          SMOOTH  Controls smoothing of contour type data.
          LIMITS  Sets testing values for good data points.
          WINDOW  Controls windowing of data within axis bounds.



          4.8  HELP

          HELP    VAX/VMS on-line help for PPLUS.
          HLP     Access on-line help from within PPLUS.














                                 CHAPTER 5

                              BEGINNERS GUIDE



               To use PPLUS a minimum of preparation is required.  See  the
          chapter  on  Getting  Started for the symbol definitions that are
          required.  Once this has been done PPLUS can be entered by typing
          PPLUS (or just PPL) in response to the VAX/VMS prompt.

               The minimum number of commands needed to read  in  data  and
          then  plot  the data are:  FORMAT (sets the input format), SKP (a
          command to position the file to a  given  record).   VARS  (tells
          PPLUS  how  the  data is arranged in each data record), RD (reads
          the data) and PLOT (create the plot) or CONTOUR (create a contour
          plot).  The name of the file containing the data can be specified
          with the RD or SKP commands.  Following are discussions of  these
          commands  and  some examples of how these commands are used.  For
          more information see the Command Description chapter.




          5.1  FORMAT

               FORMAT informs PPLUS the type  of  the  data  file  and  the
          format the data has within this file.  Valid formats are:

           UNF   -- the data is unformatted  (data type REAL)
           FREE  -- the data is formatted and in free form
           (xxx) -- the data is formatted with a format of xxx,
                    where xxx is a legal FORTRAN format, i.e.,
                    (3F10.2)




          5.2  VARS

               The next command you need to know about is VARS.  VARS is  a
          complicated  command  because  it allows great flexibility in the
          organization of the data within each file  record.   Position  of
          the  characters  1,  2,  and  3 within the command line indicates



BEGINNERS GUIDE                                                    Page 5-2


          position of the X, Y, and Z variables  within  the  data  record.
          The format of the command is:

               VARS,NGRP,A1, ...  ,Ai


          where i is the number of data values per data group
          NGRP = number of groups per record.  For example, if the data
                 file has Depth,Temperature pairs packed 3 pairs per
                 record with a format of 3(F6.1,F6.2) then NGRP=3.
          Aj = 1, 2, 3 or blank to indicate that the variable in this 
               position within the group is to be plotted as X (Aj = 1),
               Y (Aj = 2), Z (Aj = 3), or is not to be read at all 
               (Aj = blank). An example will make this clearer.

               EXAMPLE:   VARS,1,,2,1

               First arg is 1 -->      there is only 1 group per record
                                       (e.g. 1 scan per line of data) in
                                       the data file
               Second arg is blank --> Variable 1 in the data record is not
                                       to be read.  (A1 = blank)
               Third arg is 2 -->      Variable 2 in the data record is to
                                       be plotted as Y (A2 = 2)
               Fourth arg is 1 -->     Variable 3 in the data record is to
                                       be plotted as X (A3 = 1)
               No variable is to be read as Z.

          The default is VARS,1,1,2 (i.e. one group per record, first 
          variable is X, second is Y) 



               The following are examples of the VARS command.

               VARS,1,,,1 tells PPLUS that there is one group of  data  per
          record  and  to  read  the  third  number  in the record as the X
          variable.  Since no Y variable location has been specified the  Y
          variable will contain the sequence number.

               VARS,5,1,2 lets PPLUS know that there  are  five  groups  of
          data  pairs  per record.  Again the X variable is first and the Y
          second.

               VARS,1,1,2,3 informs PPLUS that the data is  X,Y,Z  triplets
          with  one  group  per  record.   The fact that X,Y, and Z appears
          tells PPLUS that the data is not on  a  regular  grid  and  PPLUS
          should  place  it  on an even grid.  The method used to place the
          data on a regular grid and the grid itself are determined by  the
          RD and CONSET commands.



BEGINNERS GUIDE                                                    Page 5-3


               VARS,1,,,,2,1 tells PPLUS that there is one  group  of  data
          per  record  where  the Y variable is the fourth number and the X
          the fifth number in the record.

               VARS,1,3 tells PPLUS that there is one  group  of  data  per
          record  and  Z  is  the  only variable in the group.  This is for
          contour data which is already gridded.  The  RD  command  defines
          how the data is stored, i.e., which index varies fastest.




          5.3  SKP AND RD

               The name of the file containing the data to be  plotted  can
          be  specified  with  either  the  SKP or the RD command.  The SKP
          command tells PPLUS to skip  records  in  the  data  file  (e.g.,
          header  records or data which should not be plotted).  Its format
          is SKP,N,FILE_NAME where N is the number or records to skip,  and
          FILE_NAME  is  the  name  of  the  data  file  and is an optional
          parameter.  If the name of the data file is  included,  the  data
          file  will  be rewound before skipping.  If the data file name is
          omitted, the file will not be rewound before skipping.

               The RD command informs PPLUS how many records  to  read  and
          what  file  to  read  them from.  If you are not making a contour
          plot, the format of the command is RD,NX,FILE_NAME  where  NX  is
          the  number of points to read from the data file and FILE_NAME is
          the name of the data file and is an optional parameter.   If  the
          data  file name is included, the data file will be rewound before
          the data is read.  If the data file name  is  omitted,  the  file
          will not be rewound before reading.

               If you are making a contour plot, the RD command  format  is
          somewhat  different.   If  Z  is  being  read  (a  3  in the VARS
          command), RD defines the size of the plotting  grid  and  prompts
          the user for the minimum and maximum values of X and Y to be used
          for   the   plotting   grid.     The    format    for    RD    is
          RD,NX,NY,TYPE,FILE_NAME  where NX and NY set the size of the grid
          for contour data read.  Specifically,  when  X,Y,Z  triplets  are
          being  read for contouring, the grid on which the data is plotted
          can be either coarser or finer or the same as the input data.  If
          NX=50 and NY=21, then the data will be plotted on a grid which is
          50 x 21 points (regardless of input  data  limits  or  gridding).
          TYPE  tells  PPLUS  whether  the data is stored by rows (X varies
          fastest)  or  columns  (Y  varies  fastest)  if   the   data   is
          already-gridded  contour  data.   Finally,  FILE_NAME is the data
          file name.  If the data file name is included, the data file will
          be  rewound  before  the  data is read.  If the data file name is
          omitted, the file will not be rewound before reading.




BEGINNERS GUIDE                                                    Page 5-4


          5.4  PLOT AND CONTOUR

               PLOT or CONTOUR initiates plotting.  An optional  label  can
          be  included  and this label will be used to title the plot.  The
          label must start with a  non-numeric  character.   See  following
          section on labels.





          5.5  EXAMPLES

               All the examples in this  section  can  be  typed  in  while
          running PPLUS interactively after typing PPLUS in response to the
          VAX/VMS prompt.  Just be sure you have first  defined  the  PPLUS
          symbols  according  to the Getting Started chapter before you try
          to do this.  Once the plot appears on your terminal,  enter  <CR>
          to  exit  from  graphics  mode and continue.  To exit from PPLUS,
          type EXIT.




          5.5.1  Unformatted Data, X-Y Plot

               The following example reads in data from an unformatted file
          with  one group of data per record.  The data to be plotted has X
          in the second position and Y in the first.  The data file has 296
          data  points in it but we will read only 100 at a time.  The data
          file also has an 8 record header that contains character data and
          must be skipped.

          ppl>FORMAT UNF
          ppl>VARS,1,2,1
          ppl>SKP,8,PPL$EXAMPLES:DEEP3000.AVG
          ppl>RD,100
          ppl>PLOT,The first 100 data points
          ppl>RD,100
          ppl>PLOT,The second 100 data points




          5.5.2  Pre-gridded Data, Contour Plot

               The  next  example  illustrates  reading  in  data   to   be
          contoured.   The  data  file is unformatted and does not have any
          header.  The data is already  gridded  with  1  value  of  Z  per
          record.   Since only Z is read from the data file, the input grid
          and the plotting grid must be identical, and are specified by the
          RD  command.   The  grid  is  34  points in the x-direction and 5
          points in the y-direction.  The PPLUS RD command prompts for  the



BEGINNERS GUIDE                                                    Page 5-5


          minimum  and  maximum  for  the  X-Y  contouring  grid.   In this
          example, the grid is 34 points in the x-direction from 10 to -6.5
          units  and  is 51 points in the y-direction from 0 to -500 units.
          PPLUS will read Z values from the data  file  assuming  x  varies
          fastest.   This  means  that  the  Z  values  on  the  data  file
          correspond to the following x,y pairs:

               x     y
            10.0     0
             9.5     0
             9.0     0
              .
              .
            -6.5     0
            10.0   -10
             9.5   -10
             9.0   -10
              .
              .
            -6.5   -10
              .
              .


          ppl>FORMAT,UNF
          ppl>VARS,1,,3
          ppl>RD,34,51,1,PPL$EXAMPLES:CTDDAT.DAT
          ENTER XMIN,XMAX,YMIN,YMAX
          rd>10,-6.5,0,-500
          ppl>CONTOUR,A test plot for contouring




          5.5.3  Ungridded Data, Contour Plot

               This example shows the reading in of ungridded contour data.
          The data is unformatted with Y,X,Z the order of the triplets.  We
          define the grid for plotting to be 22 x 11 with X and Y limits of
          1,22  and -.033,.0576.  Although the data file contains less than
          1000 points, we can give PPLUS a much larger number to read,  and
          it will stop at the end-of-file without error.

          ppl>FORMAT,UNF
          ppl>VARS,1,2,1,3
          ppl>RD,22,11,PPL$EXAMPLES:GRIDWI.FMT
          ENTER NUMBER PTS TO READ
          rd>1000
          ENTER XMIN,XMAX,YMIN,YMAX
          rd>1,22,.033,.567
          ppl>CONTOUR,An example of contouring with ungridded data




BEGINNERS GUIDE                                                    Page 5-6


          5.5.4  Time Series Plot

               This example demonstrates the reading in of time series data
          and  setting  up  the  x  axis  to be a time axis.  The data file
          contains a sequence number, which is  the  day  of  the  year  or
          Julian Day and temperature.  Since the sequence number increments
          by 1 for 1 day, and delta-time is 1  day  by  default  in  PPLUS,
          there  is no need to include the delta-time in the TAXIS command.
          The TAXIS  command  tells  PPLUS  that  the  time  series  has  a
          delta-time  of  1440 minutes (the default) and that the time axis
          is to be turned on.  (The alternate form  of  the  TAXIS  command
          would  be "taxis,1440,on".) The TIME command tells PPLUS that the
          time axis will start at 0000 1 Jul 85, end at 0000 1 Dec 85,  and
          that  a  sequence number of 1 corresponds to a time of 1200 1 Jan
          85.  The YLAB command sets the y-axis label.  The LIMITS  command
          tells  PPLUS  to  omit data where Y = 0.  The VARS command is not
          needed since the data is formatted with one  group  of  data  per
          record,  with  the  X  variable  first and the Y variable second,
          which is the VARS command default.  The CROSS command  suppresses
          the  drawing  of  a solid line through x=0, y=0 on the plot.  The
          BOX command suppresses the drawing of a  box  around  the  entire
          plotting  region.   The SKP command names the data file and skips
          past the 5 header records at the beginning of the data file.  The
          RD  command reads the data.  The PLTYPE command sets the plotting
          medium to be both Tektronix compatible and  binary  suitable  for
          routing  to  hardcopy  devices.   The PLTNME sets the name of the
          output plot file.  The PLOT command generates the plot.  See  the
          Command  Description  chapter for a full description of all PPLUS
          commands.

          ppl>format (17x,f3.0,7x,f5.0)
          ppl>taxis,on
          ppl>time,W8507010000,W8512010000,W8501011200
          ppl>ylab,Air Temperature
          ppl>limits,0,yeq,on
          ppl>cross,0
          ppl>box,off
          ppl>skp,5,ppl$examples:atlas.dat
          ppl>rd
          ppl>pltype,2
          ppl>pltnme,atlas.plt
          ppl>plot,ATLAS Air Temperature at 2N 165E


               Additional examples are in the directory PPL$EXAMPLES in the
          form  of  PPLUS command files, which are the files with extension
          .PPC.  Use the VAX/VMS command "DIR  PPL$EXAMPLES:*.PPC"  to  see
          what  the  file  names are.  You can run these command files with
          the VAX/VMS command "PPLUS PPL$EXAMPLES:xxx.PPC",  where  xxx  is
          the  name  of  the  PPLUS command file.  The file will generate a
          plot on your terminal.  Enter a <CR> to exit from  graphics  mode
          and  return  to the VAX/VMS prompt.  (Be sure that you have first
          defined the  PPLUS  symbols  according  to  the  Getting  Started



BEGINNERS GUIDE                                                    Page 5-7


          chapter before you do this.) See the chapter on Command Files for
          more information about using PPLUS command files.

               You can copy these PPLUS command files to your own directory
          with  the VAX/VMS command "COPY PPL$EXAMPLES:*.PPC []".  Then you
          can run them with the VAX/VMS command "PPLUS xxx.PPC", where  xxx
          is  the  name of the PPLUS command file.  You can experiment with
          PPLUS commands by editing the PPLUS command file  to  change  the
          appearance  of  the  plot, and then run PPLUS again with your new
          command file.














                                 CHAPTER 6

                            ROUTING PLOT FILES




          6.1  VAX/VMS

          6.1.1  Plot Files And Mom

               PPLUS plot files are named ZETA.PLT by default (this can  be
          changed  with  the  PLTNME  command).   A  graphics postprocessor
          called MOM is available to reformat these binary plot  files  and
          route  them  to  a  graphics  device.  MOM submits a batch job to
          BETA$LOPRI or BETA$BATCH.  When the batch job has  finished,  the
          original  plot  files  will  have  been  renamed from file.ext to
          file.PLT_HHMMSS, and the plots queued to the appropriate  device.
          A log file with the name MOM_HHMMSS.LOG is placed in the original
          directory when the MOM option /LOG is selected.

               The command is (brackets [] enclose optional information):

               MOM [arg1 [arg2 ...]]

               The  arguments  for  MOM  are  order  independant  and   are
          separated by spaces.  The arguments are:

           [F[ILE]=]file name  (default  ZETA.PLT)
           [D[EVICE]=]device   (e.g. TEK, VER etc, default VER)
           S[CALE]=scale factor (default 1)
           G[RACE]=grace distance  (inches, default = 0.25)
           W[IDTH]=width (paper width CAL only, default = 11.5)
           C[PLOT]="cplot arguments" (CPLOT parameters CAL only, 
                   default=NULL)
           [NO]ROT[ATE]   (rotate the plot, default NOROT)
           [NO]CEN[TER]   (center the plot, default CENTER)
           /[NO]SAVE      (save the input file, default /SAVE)
           /[NO]LOG       (create a batch log file, default /NOLOG)
           /SMALL, /LARGE or /TRANS  (type of hard copy made,
                                      default /SMALL)


           File names which are the same as a legal device name



ROUTING PLOT FILES                                                 Page 6-2


                  (e.g. VER, TEK, etc.) are not allowed.  The file name
                  can contain any wild carding that is valid with the
                  VAX/VMS rename command.  The default file extension
                  is .PLT.




          6.1.2  Plotting Devices


               VER Batch plot on Versetec V80 printer/plotter

               TEK Interactive plot on Tekronix compatible terminal

               CPY Batch plot on Tekronix 4691 hardcopy unit

               CAL Batch plot on CALCOMP plotter

               HP Batch plot on HP7550A plotter

               LN03 Batch plot on TMAP1::  LN03 printer/plotter

               HPT Batch plot on TMAP1::  HP7475





          6.1.3  Examples

               1) $MOM ?

               Will cause MOM to prompt for inputs.  If the CPLOT  argument
          is a ?  you are then prompted for the CPLOT inputs.


               2) $MOM CTD110W VER SCALE=1.25 ROTATE

               Will instruct MOM to create a VERSATEC plot  from  the  meta
          file  CTD110W.PLT,  rotate  the  plot 90 degrees on the paper and
          rescale the plot by a factor of 1.25.


               3) $MOM CAL CPLOT=""

               Will have MOM create a CALCOMP plot using ZETA.PLT and  call
          CPLOT  with the default parameters.  If CPLOT is omitted then MOM
          will prompt for the CPLOT command line (omitting CCFILE).

          4) $MOM TEMP.PLT;* CAL CPLOT="/P1=BLK:.3"



ROUTING PLOT FILES                                                 Page 6-3


               Will cause MOM to send all the versions of TEMP.PLT  to  the
          CALCOMP with operator instructions to have pen 1 be black ink pen
          of 0.3 mm width.

          5) $MOM HP *.MYPLOT;* /TRANS

               Will send all plots with extension  .MYPLOT  to  the  HP7550
          plotter with operator instructions to plot on transparencies.
















                                 CHAPTER 7

                            PPLUS COMMAND FILES




          7.1  INTRODUCTION

               PPLUS can be run using a PPLUS command  file  that  contains
          the same commands used by PPLUS interactively.  The file can have
          any name or extension, but the default extension is .PPC.  To run
          a PPLUS command file named CMD.PPC, you can enter PPLUS by typing
          PPLUS CMD.PPC in response to the VAX/VMS prompt, or you can enter
          PPLUS in the usual way and give the PPLUS command @CMD.PPC.  (See
          @ in the chapter on Command Description.)

               Each time PPLUS is used, an echo  file  (named  ECHO.DAT  by
          default)  is  generated.   This  file can be edited (it should be
          renamed) with any VAX text editor and used  as  a  PPLUS  command
          file in subsequent PPLUS sessions.





          7.2  SYMBOL SUBSTITUTION

               PPLUS allows symbol substitution  in  a  manner  similar  to
          VAX/VMS  symbols.   Global  and  local  symbols  are supported in
          conjunction with nested command files and parameter passing.  The
          SET  and SHOW commands create, modify and list the symbols.  When
          initially entering PPLUS (i.e., at the first command  level)  the
          symbols  are global and available to all command levels.  At each
          subsequent command level, local symbols are created and  used  by
          default.   Global  symbols  are used when no local symbol exists.
          If the symbol name is preceded by a star (*), the  global  symbol
          will be created, modified or substituted.

               Parameters passed via the @ command line are named  P1,  P2,
          P3,  etc...  just as they are in VAX/VMS.  Symbols are recognized
          by PPLUS by being enclosed by single quotes.   Character  strings
          can be enclosed in double quotes.  For example:

           SET TEMP "This is a test label"



PPLUS COMMAND FILES                                                Page 7-2


           XLAB 'temp'

          will have the same effect as:

           XLAB This is a test label


               Several symbols  are  predefined.   'DATE'  and  'TIME'  and
          contain  the  current  date  and time.  Date and time formats are
          dd-mmm-yy and hh:mm:ss.  In addition,  P1  through  Pn  are  also
          predefined  if  the  corresponding  argument was passed via the @
          command.  For example, the command procedure PLOTIT.PPC could  be
          executed  in  PPLUS  by typing @PLOTIT 110W Temperature.  Then in
          the procedure PLOTIT, the symbol P1 will have  the  value  "110W"
          and the symbol P2 will have the value "Temperature".

               Symbols can also be defined and used  in  an  array  format,
          i.e.,  'P(3)'  will  get  symbol  P3  and 'label(12)' will access
          symbol LABEL12.

               To have a single quote (') in the symbol or command line two
          single  quotes  must be used ('').  To have a double quote (") in
          the command line two double quotes ("") are required.

               Here is a sample PPLUS command file which demonstrates  some
          of the new, powerful PPLUS features.  In this example, the symbol
          P1 has the value 110W.

           pltnme,'p1'.plt
           format,(f5.0,15x,f15.0)
           vars,1,1,2
           skp,1,'p1'.dat
           rd,60
           debug,on
           show p1
           debug,off
           plot,@TRMonthly data 1979-83 at 'P1' ('date' 'time')


               The proceeding PPLUS command file (named  PLOTIT.PPC)  could
          be  called  repeatedly  in  PPLUS  for different data files named
          110W.DAT, 140W.DAT, etc.  by entering the PPLUS commands  @PLOTIT
          110W,  @PLOTIT  140W,  etc.   The  resulting plot files, ECHO.DAT
          files and graphs would be identified by the data  file  names  of
          110W,  140W, etc.  The graph title will also include the time and
          date when the graph was made.




PPLUS COMMAND FILES                                                Page 7-3


          7.3  GENERAL GLOBAL SYMBOLS

               The global symbols set by PPLUS to allow information  to  be
          available in the command procedure are:

           SYMBOL             COMMAND      DESCRIPTION 

          DATE                             The current date dd-mmm-yy
          PPL$COMMAND_FILE    @            The current command file name.
          PPL$EOF             RD,RWD,SKP   "YES" if an EOF was read.
          PPL$FORMAT          FORMAT       The current format.
          PPL$HEIGHT          SIZE         Height of the box.
          PPL$INPUT_FILE      RD,SKP,RWD   The current input file.
          PPL$LF_A            LINFIT       Constant from fit y= a + b*x
          PPL$LF_A_STDEV      LINFIT       Standard error of A.
          PPL$LF_B            LINFIT       Constant from fit.
          PPL$LF_B_STDEV      LINFIT       Standard error of B.
          PPL$LF_R2           LINFIT       Regression coefficient squared.
          PPL$LF_RES_VAR      LINFIT       Residual variance.
          PPL$LF_VAR          LINFIT       Total variance.
          PPL$LINE_COUNT      -            The number of the last line 
                                           read.
          PPL$PLTNME          PLTNME       The name of the plot file.
          PPL$RANGE_INC       %RANGE       See Advanced Commands Chapter
          PPL$RANGE_HIGH      %RANGE       See Advanced Commands Chapter
          PPL$RANGE_LOW       %RANGE       See Advanced Commands Chapter
          PPL$TEKNME          TEKNME       The name of the tektronix file.
          PPL$VIEW_X          VPOINT       X viewpoint
          PPL$VIEW_Y          VPOINT       Y viewpoint
          PPL$VIEW_Z          VPOINT       Z viewpoint
          PPL$WIDTH           SIZE         Width of the box.
          PPL$XFACT(n)        TRANSXY      Xfact for line n.
          PPL$XLEN            AXLEN        Length of X axis.
          PPL$XOFF(n)         TRANSXY      Xoff for line n.
          PPL$XORG            ORIGIN       Distance between origin and left
                                           edge.
          PPL$XFIRST(n)       -            X value for first data point in 
                                           line n.
          PPL$XLAST(n)        -            X value for last data  point in
                                           line n.
          PPL$XMAX            RD           Xmax of contour grid
          PPL$XMIN            RD           Xmin of contour grid
          PPL$XMAX(n)         -            Xmax for valid data in line n.
          PPL$XMIN(n)         -            Xmin for valid data in line n.
          PPL$YFACT(n)        TRANSXY      Yfact for line n.
          PPL$YLEN            AXLEN        Length of Y axis.
          PPL$YOFF(n)         TRANSXY      Yoff for line n.
          PPL$YORG            ORIGIN       Distance between origin and 
                                           bottom edge.
          PPL$YFIRST(n)       -            Y value for first data point in 
                                           line n.
          PPL$YLAST(n)        -            Y value for last data  point in
                                           line n.



PPLUS COMMAND FILES                                                Page 7-4


          PPL$YMAX            RD           Ymax of contour grid
          PPL$YMIN            RD           Ymin of contour grid
          PPL$YMAX(n)         -            Ymax for valid data in line n.
          PPL$YMIN(n)         -            Ymin for valid data in line n.
          PPL$ZMAX            -            Zmax for valid contour data.
          PPL$ZMIN            -            Zmin for valid contour data.
          TIME                -            The current time hh:mm:ss





          7.4  EPIC GLOBAL SYMBOLS

               The  following  global  symbols   set   by   PPLUS   contain
          information from EPIC time series data headers:

           SYMBOL                    COMMAND DESCRIPTION 

          PPL$EPIC_COMMENT_DATA(n)   RD      Data comment from header.
          PPL$EPIC_COMMENT_FIRST(n)  RD      Data comment from header.
          PPL$EPIC_COMMENT_SECOND(n) RD      Data comment from header.
          PPL$EPIC_DEPTH(n)          RD      Depth of measurement.
          PPL$EPIC_DESCRIPT(n)       RD      EPIC series descriptor.
          PPL$EPIC_EXPERIMENT(n)     RD      Experiment identifier.
          PPL$EPIC_LATITUDE(n)       RD      Latitude.
          PPL$EPIC_LONGITUDE(n)      RD      Longitude.
          PPL$EPIC_MOORING(n)        RD      Mooring identifier.
          PPL$EPIC_PROJECT(n)        RD      Project identifier.
          PPL$EPIC_XLAB(n)           RD      X-axis label.
          PPL$EPIC_YLAB(n)           RD      Y-axis label.


               The  following  global  symbols   set   by   PPLUS   contain
          information from EPIC CTD data headers:

           SYMBOL                    COMMAND DESCRIPTION 

          PPL$EPIC_CAST(n)           RD      CTD Cruise and Cast identifier
          PPL$EPIC_COMMENT_FIRST(n)  RD      Data comment from header.
          PPL$EPIC_COMMENT_SECOND(n) RD      Data comment from header.
          PPL$EPIC_DATE(n)           RD      CTD Cast Date (GMT)
          PPL$EPIC_LATITUDE(n)       RD      Latitude.
          PPL$EPIC_LONGITUDE(n)      RD      Longitude.
          PPL$EPIC_XLAB(n)           RD      X-axis label.
          PPL$EPIC_YLAB(n)           RD      Y-axis label.


               The  following  global  symbol   set   by   PPLUS   contains
          information about the EPIC data file:

           SYMBOL                    COMMAND DESCRIPTION 



PPLUS COMMAND FILES                                                Page 7-5


          PPL$EPIC_DATAFILE(n)       RD      Data file name
          PPL$INPUT_FILE                     RD EPIC/pointer file



          7.5  COMMAND FILE LOGIC

               There are several commands that  enable  the  user  to  make
          command  files  more  like  small  programs.   These commands are
          similar to FORTRAN's block IF and C's WHILE loops.  Commands have
          been introduced that enable the user to increment and decrement a
          counter stored in a symbol by one.   In  order  to  make  command
          files more readable leading blanks and tabs are ignored.

               The syntax for the PPLUS commands is given  in  the  Command
          Description chapter.

          EXAMPLES:

          In this example, PPLUS is exited when an end-of-file is 
          encountered by the RD command.  This illustrates both the
          block IF and the use of the global PPLUS symbol PPL$EOF.

                    RD
                    IF PPL$EOF .EQ. "YES" THEN
                        EXIT
                    ENDIF

          In the following example, the size of the plot is set to val by
          val inches if the value of the symbol val is less than or equal
          to 13 otherwise the size is set to 13 x 13. 

                    IF VAL .LE. 13 THEN
                        SIZE 'VAL' 'VAL'
                    ELSE
                        SIZE 13 13
                    ENDIF


          In the next example, if P1 is null then P1 is set to
          TEMPORARY.PLT and then the plot name is set to the value of
          the symbol P1. 

                    IF P1 .EQ. "" THEN
                        SET P1 TEMPORARY.PLT
                    ENDIF
                    PLTNME 'P1'


          This WHILE loop results in 10 plots of 100 points each from
          data file DLDK1039.DAT. (PPL$LINE_COUNT is a PPLUS defined 
          symbol for the sequence number of the last data line read.)



PPLUS COMMAND FILES                                                Page 7-6


                    SKP,DLKD1039.DAT
                    WHILE PPL$LINE_COUNT .LE. 10 THEN
                        RD,100
                        PLOT
                    ENDW



          7.6  ARITHMETIC

               Simple arithmetic can be performed using PPLUS symbols.  The
          commands  that  perform these function are SET, INC and DEC.  The
          INC and  DEC  functions  are  primarily  used  to  increment  and
          decrement counters in WHILE loops.  The following WHILE loop uses
          the counter to set the line type to a solid line for each line to
          be  plotted  (PPL$LINE_COUNT  is  a  PPLUS defined symbol for the
          number of the last data line read):

                    SET COUNT 1
                    WHILE COUNT .LE. PPL$LINE_COUNT THEN
                        LINE,'COUNT',,0
                        INC COUNT
                    ENDW

               The SET command can be used to perform simple arithmetic  on
          PPLUS  symbols.  The syntax for these arithmetic expressions have
          the form:

               num1 op num2,

          where op is +, -, * or / (addition,  subtraction,  multiplication
          or  division)  and num1 and num2 are numbers.  The numeric values
          must be separated from the operator op  by  spaces.   The  string
          will  be  used exactly as it appears if enclosed by double quotes
          (").  The following example centers a moveable label  0.5  inches
          above  the  top axis (PPL$XLEN and PPL$YLEN are PPLUS symbols for
          the X and Y axis lengths):

                    SET XPOS 'PPL$XLEN' / 2.0
                    SET YPOS 'PPL$YLEN' + 0.5
                    LABS/NOUSER,1,'XPOS','YPOS',0,"A centered label"



          7.7  SYMBOL ARRAYS

               As described  in  the  SYMBOL  SUBSTITUTION  section,  PPLUS
          symbols  can  be  defined  and used as arrays.  There are several
          general PPLUS global symbols which are also  defined  as  arrays,
          such  as  PPL$XLAST(n)  and PPL$YLAST(n), the last x and y values
          for data line n.  The array index, in parentheses, can be  either
          a number or a PPLUS symbol.  Examples will illustrate this.



PPLUS COMMAND FILES                                                Page 7-7


               The following piece of a PPLUS command  file  uses  moveable
          lables  to  write  the line number to the right of the last point
          plotted for the last line read in.   It  uses  the  global  PPLUS
          symbols PPL$XLAST(n), PPL$YLAST(n) and PPL$LINE_COUNT.

                    SET XPOS 'PPL$XLAST(PPL$LINE_COUNT)'
                    SET YPOS 'PPL$YLAST(PPL$LINE_COUNT)'
                    LABS 'PPL$LINE_COUNT','XPOS','YPOS',-1,'PPL$LINE_COUNT'

               The array index can also be a user defined symbol.   In  the
          following  example, the array MON contains the names of the first
          3 months of the year.  The graph title will be "Daily Values  for
          the Month of FEBRUARY".

                    set mon(1) "JANUARY"
                    set mon(2) "FEBRUARY
                    set mon(3) "MARCH"
                    .
                    .
                    .
                    set count 2
                    .
                    .
                    .
                    plot,"Daily Values for the Month of 'mon(count)'

               The  index  of  an  array  (inside  parentheses)   will   be
          interpreted  according  to  the  following  rules:  1) if it is a
          number, that number will be used as the array index, 2) if it  is
          not  a number, it will be interpreted as a symbol, 3) if it is in
          single quotes, it will be interpreted as a symbol.



          7.8  SPECIAL FUNCTIONS

               The functions described in this sections  are  all  accessed
          with  the  SET  command.   They can be accessed only with the SET
          command.  The functions enable string manipulation and formatting
          within  PPLUS  symbol values.  The PPLUS functions are similar to
          some of the VAX/VMS lexical functions.

               The general syntax is :

                    SET sym $function (arg1, arg2,...),

          where "sym" is the symbol set by the function and  "function"  is
          the  name  of  the  PPLUS  function.   PPLUS  functions and their
          arguments  are  described  in  the  following  sections.    Where
          function  arguments  are indicated as symbols, they must be PPLUS
          symbols and cannot be  strings.   Where  function  arguments  are
          indicated as strings, they can be enclosed in double quotes.



PPLUS COMMAND FILES                                                Page 7-8


          7.8.1  $EDIT

               The command is :

                    SET sym_out $EDIT (sym_in, arg1 [ arg2 arg3...] )

          where:

          sym_out = symbol set by the function
          sym_in  = symbol on which function is to work
          arg1    = upcase - changes string in sym_in to upper case
                    trim - trims leading and trailing blanks from sym_in
                    compress - removes extra blanks from sym_in (reduces
                               each group of blanks to a single blank)
                    collapse - removes all blanks from sym_in

          If multiple arguments are used, they can be separated 
          by blanks, e.g., SET sym $EDIT(sym_in,UPCASE COLLAPSE).
          If commas are used as separaters, the entire set of 
          arguments must be enclosed in quotes, e.g.,
          SET sym $EDIT(sym_in,"UPCASE,COLLAPSE").

          Example:

                    SET S1 "depth"
                    SET S2 $EDIT (S1,UPCASE)

          This results in S2 having the value "DEPTH".


          Example:
                    SET S1 "  depth    "
                    SET S2 $EDIT (S2,UPCASE TRIM)

          This results in S2 having the value "DEPTH".  



          7.8.2  $EXTRACT

               This function extracts selected characters  from  the  input
          string.  The first character in the string is in position 1.  The
          command is :

                    SET sym_out $EXTRACT (start,length,sym_in)

          where:

          sym_out = symbol set by the function
          start   = starting character position
          length  = length of character string to be extracted
          sym_in  = symbol on which function is to work



PPLUS COMMAND FILES                                                Page 7-9


          Example:

                    SET S1 "February"
                    SET S2 $EXTRACT(1,3,S1)

          This results in S2 having the value "Feb".





          7.8.3  $INTEGER

               This function converts a  number  to  integer  format.   The
          command is :

                    SET sym_out $INTEGER (sym_in)

          where:

          sym_out = symbol set by the function
          sym_in  = symbol on which function is to work

          Example:

                    SET MON 1
                    .
                    .
                    .
                    INC MON
                    SET INT_MON $INTEGER(MON)

          In this example, the symbol MON has been incremented, 
          and will have the value "2.00".  The symbol INT_MON
          will have the value "2".



          7.8.4  $LENGTH

               This function returns the length of the input  string.   The
          command is :

                    SET sym_out $LENGTH (sym_in)

          where:

          sym_out = symbol set by the function
          sym_in  = symbol on which function is to work

          Example:

                    SET S1 "February"



PPLUS COMMAND FILES                                               Page 7-10


                    SET S2 $LENGTH(S1)

          This results in S2 having the value "8".



          7.8.5  $LOCATE

               This function locates a substring in the input string.   The
          first character in the string is in position 1.  The command is :

                    SET sym_out $LOCATE (substrg,sym_in)

          where:

          sym_out = symbol set by the function
          substrg = string to be located
          sym_in  = symbol function on which function is to work

          Example:

                    SET S1 "JAN 21,1987"
                    SET S2 $LOCATE(",",S1)

          This results in S2 having the value "7".



          7.8.6  $ELEMENT

               This function extracts an element from an  input  string  in
          which  the  elements are separated by a specified delimiter.  The
          command is :

                    SET sym_out $ELEMENT (pos,delim,sym_in)

          where:

          sym_out = symbol set by the function
          pos     = position of element to be extracted
          delim   = delimiter
          sym_in  = symbol on which function is to work

          Example:

                    SET MONTH "JAN/FEB/MAR/APR/MAY/JUN/JUL"
                    SET MON $ELEMENT(3,"/",MONTH)

          This results in MON having the value "MAR".


          Example:



PPLUS COMMAND FILES                                               Page 7-11


                    SET MONTH "JAN/FEB/MAR/APR/MAY/JUN/JUL"
                    SET COUNT 1
                    WHILE COUNT .LE. 7 THEN
                      SET MON(COUNT) $ELEMENT('COUNT',"/",MONTH)
                      INC COUNT
                    ENDW

          This results in MON(1) = "JAN", MON(2) = "FEB", MON(3) = "MAR",
          MON(4) = "APR", MON(5) = "MAY", MON(6) = "JUN", MON(7) = "JUL".
















                                 CHAPTER 8

                                  LABELS




          8.1  AXIS LABELING

               Commands affecting the labeling of the axes are:

          XAXIS   Controls numeric labeling and tics on the x-axis.
          YAXIS   Controls numeric labeling and tics on the y-axis.
          AXATIC  Sets number of large tics automatically for x and y.
          AXLABP  Locates axis labels at top/bottom or left/right of plot.
          AXLEN   Sets axis lengths.
          AXLINT  Sets label interval for axes.
          AXLSIG  Sets axis label heights.
          AXNMTC  Sets number of small tics between large tics on axes.
          AXNSIG  Sets no. significant digits in numeric axis labels (auto 
                  only).
          AXSET   Allows omission of plotting of any axis.
          AXTYPE  Sets axis type for x- and y-axis.
          XFOR    Sets format of x-axis numeric labels.
          YFOR    Sets format of y-axis numeric labels.
          XLAB    Sets label of x-axis.
          YLAB    Sets label of y-axis.

               The numeric axis labels are drawn such  that  zero  will  be
          labelled  if  it occurs between the low and high axis limits.  If
          zero does not occur, then the first large tic (from the bottom or
          left)  will  be  labelled.  The large tics are forced to occur at
          integer multiples of the tic interval.




          8.2  EMBEDDED STRING COMMANDS





LABELS                                                             Page 8-2


          8.2.1  Fonts

               All labels in PPLUS can be  plotted  using  any  one  of  21
          character  fonts  and  11  symbol  fonts.  The default font is SR
          (Simplex Roman) and other fonts are called by preceding their two
          letter  abbreviation  by  an  @,  i.e.,  @CI for complex itallic.
          Symbol fonts are called by using the symbol number,  i.e.,  @MA01
          plots  the  first  symbol in MATH and @MA12 will plot the twelfth
          symbol.  Font changes (of the form @XX) can be  imbedded  in  any
          label string (e.g., XLAB, YLAB, PLOT commands).

               @font selects "font" as the character or symbol font  to  be
          used, where the font abbreviations are listed below.

                  Character Fonts

                  SR Simplex Roman   (default)
                  DR Duplex Roman
                  TR Triplex Roman
                  CR Complex Roman
                  AS ASCII Simplex Roman
                  AC ASCII Complex Roman
                  CS Complex Script
                  TI Triplex Italic
                  GE Gothic English
                  IR Indexical complex Roman
                  SS Simplex Script
                  CI Complex Italic
                  II Indexical complex Italic
                  SG Simplex Greek
                  CG Complex Greek
                  IG Indexical complex Greek
                  GG Gothic German
                  GI Gothic Italian
                  CC Complex Cyrillic
                  AR Cartographic Roman
                  AG cartographic Greek

                  Symbol Fonts

                  ZO Zodiac
                  MU Music
                  EL Electrical
                  WE Weather
                  MA Math
                  SM Simplex Math
                  MP Map
                  LM Large Math
                  IZ Indexical Zodiac
                  IM Indexical Math
                  CA Cartographic



LABELS                                                             Page 8-3


               A clear font command @CL is available to change the  default
          font.   The  next font called after a @CL becomes the new default
          font.  The font is reset to the default  at  the  start  of  each
          label.   The  command  DFLTFNT  can  also  be  used to change the
          default font to one of your choice.

               Control characters for the two ASCII fonts AS and AC must be
          preceded   by   an   <ESC>  (ascii  code=27).   For  example,  to
          superscript while using the ASCII fonts you must have  <ESC>^  in
          the label preceed the character to superscript.



          8.2.2  Pen Selection

               The pen may also  be  selected  by  giving  the  change  pen
          command  @Pn,  where n is the character 1-9 and A-G.  This allows
          the selection of up to 16 pens/colors.  The  color  and  font  is
          reset  to the default font and previous color after the character
          string is drawn.  The PEN command  can  be  used  to  change  the
          default color by typing PEN,0,default_color.

               If you need to select a color index beyond the range  of  P1
          through  PG,  you  can  use  the change color command @Cnnn where
          "nnn" is a 3-digit color index.  (It must be 3 digits.)



          8.2.3  Character Slant

               The slant used in drawing the fonts may be changed by  using
          the  command  @Zn,  where  n  is the character 0-9 and A-G.  This
          allows the  selection  of  slant  angles  from  0  to  45  in  16
          increments.   The  slant  is  reset  to  zero after the character
          string is drawn.



          8.2.4  Subscripting, Superscripting And Back Spacing

               An ^ (up arrow) imbedded in any label string will cause  the
          next  character to be drawn superscripted, an _ (underscore) will
          draw it subscripted, and a \ (backslash) backspaces over the last
          character drawn.  The control characters ^, _ and \ are available
          in the two ASCII  fonts  AS  and  AC  by  preceding  the  control
          character by an <ESC> (ASCII code=27).  For example, to subscript
          while using the ASCII fonts you must have  <ESC>_  in  the  label
          preceed the character to subscript.














                                 CHAPTER 9

                               DATA FORMATS




          9.1  SEQUENTIAL FORMATS

          The format to be used  in  reading  from  a  sequential  file  is
          defined  by  the commands FORMAT, VARS, and RD.  Some definitions
          are useful:

                  NVAR - the number of variables per group
                  NGRP - the number of groups per record
                  NREC - the total number of records

               For example, if the data consists of depth, u, v, t and  the
          format  is  8F10.2  (the  format  statement must be for an entire
          record) with two groups per record, the data would look like

          D     U     V     T     D     U     V     T

          and NGRP=2, NVAR=4.

               If you wanted to plot D as the Y variable, T as the X  then,
          FORMAT   (8F10.2)   would  be  the  correct  FORMAT  command  and
          VARS,2,2,,,1 would be the correct VARS command.  (U and V are not
          read or plotted.)

               However, if the format was  F10.2,30X,2F10.2,30X,F10.2  then
          FORMAT   (F10.2,30X,2F10.2,30X,F10.2)  and  VARS,2,2,1  would  be
          appropriate.

               If the data is unformatted the meanings of NVAR and NGRP are
          unchanged.   Unformatted  data is specified by the FORMAT command
          FORMAT,UNF.

               Reading will automatically stop at the end of the  file  and
          properly store the data.





DATA FORMATS                                                       Page 9-2


          9.2  BIBO FORMAT

          The BIBO data format consists of data files created using the DSF
          routines  and  a  145  word header in the BIBO format.  This data
          format is in the standard dsf file format for data storage.





          9.3  EPIC FORMAT

          This is the standard format for data from  the  EPIC  data  base.
          The  data  files  are  binary  sequential files with at least one
          header of 8 80-character lines followed by data  records  with  1
          data  scan per record.  When the FORMAT,EPIC command is used, the
          file name specified with the RD, SKP and RWD commands  refers  to
          the  EPIC  or  pointer  file.  Variables to be read are specified
          with the EVAR command.  Both time series EPIC data files and  CTD
          EPIC  data  files are recognized by PPLUS.  The /CTD qualifier on
          the FORMAT command tells PPLUS which type of EPIC data  is  being
          read.





          9.4  DSF FORMAT

          This data format is that produced by the DSF  routines  with  the
          header  and data in PPLUS format.  The format must be followed to
          insure that PPLUS can interpret the data file read correctly.

               A single data file consists of a single  header  record  and
          any  number  of data records followed by an EOF.  The header must
          be either an array or other sequentially organized data set of 38
          real variables.  Below is the expected format.

            INT WORD  DESCRIPTION 

            1         XPTS
            3         ZMIN       first four created by CLSDSF
            5         ZMAX
            7         ZMEAN
            9         XMIN      minimum x value (real)
            11        XMAX      maximum x value (real)
            13        KX        number of x grid points (integer*4)
            15        YMIN      minimum y value (real)
            17        YMAX      maximum y value (real)
            19        KY        number of y grid points (integer*4)
            21        ITYPE     data type 0= 2-d set, 1= 1-d set 
                      (integer*4)
            23-38     LAB(16)   main label hollerith (integer*2)
            39        NCH       number of characters is LAB (integer*4)



DATA FORMATS                                                       Page 9-3


            41-56     IXLAB(16) x axis label hollerith  (integer*2)
            57        NXLB      number of characters in IXLAB (integer*4)
            59-74     IYLAB(16) y axis label hollerith  (integer*2)
            75        NYLB      number of characters in IYLAB (integer*4)


               All labels use SYMBEL to generate  the  plotted  characters.
          The  labels  are  optional,  but  if not used they should contain
          blanks.





          9.4.1  ITYPE=0

          Data must be stored in a linear array as:

          Z(1,1),Z(2,1),...,Z(KX,1),Z(1,2),...,...,Z(KX,KY)

          or as a 2-d array where the array is dimensioned as KX,KY.

               Assuming the following arrays exist,  ITYPE=0  data  can  be
          created  as follows:  HEAD(38),Z(25,50) NOTE:  use EQUIVALENCE to
          set the integers in the real array.
            CALL OPNDSF(file_name,'WR',ILUN)
            CALL WRHDSF(ILUN,38,HEAD)
            CALL WRDDSF(ILUN,1250,Z)
            CALL CLSDSF(ILUN)
          where file_name is the file name and ILUN is the logical unit  to
          be used.





          9.4.2  ITYPE=1

          Data must be stored as a linear array as:

          X(1),X(2),...,X(KX),Y(1),Y(2),...,Y(KX)

          in this case KX= length of the series and KY must be  set  to  1,
          there  must  be  KX  of  each  X  and  Y in the data set.  Given,
          HEAD(38),X(200),Y(200) KX=100 then,
            CALL OPNDSF(file_name,'WR',ILUN)
            CALL WRHDSF(ILUN,38,HEAD)
            CALL WRDDSF(ILUN,KX,X)
            CALL WRDDSF(ILUN,KX,Y)
            CALL CLSDSF(ILUN)
          where KX is the number of pairs.  The DSF routines are  available
          in     a     user     library     by     Task    building    with
          DISK1:[DENBO.PPL]OURLIB/LIB.














                                CHAPTER 10

                             ADVANCED COMMANDS




               This chapter describes PPLUS primitive plot commands.   With
          these  commands,  the  user  can  make  a plot with several x- or
          y-axes.   The  location  of  each  axis  can  be  specified.   To
          distinguish them from the standard PPLUS commands, these commands
          all begin with "%".

               These % commands can be entered only from  a  PPLUS  command
          file,  and  can  not  be entered interactively from the keyboard.
          Each command is implemented as it is read from the command  file.
          Specifically,  when  the  %XAXIS  command  is read from a command
          file, an x-axis is immediately drawn on the graph.  By  contrast,
          the  standard  PPLUS  XAXIS command simply sets x-axis parameters
          and the x-axis is not drawn on the graph until a plotting command
          such  as  PLOT  is  issued.   The  % commands give the user great
          control over the graphics display, but must  be  used  carefully.
          No PPLUS error messages are issued for illegal % commands.  The %
          commands can not be used with the MULTPLT command.  See the notes
          with  each command description and the example at the end of this
          chapter.

               Command descriptions follow.


     %OPNPLT/qualifier


               Opens the plot by putting  the  terminal  into  and  out  of
          graphics mode and setting /QUIET.

            Valid qualifiers are:

            /[NO]OVERLAY Controls whether PPLUS overlays the
                         plot on the preceeding plot. The default
                         is /OVERLAY which causes the plot
                         to be overlaid without erasing the last 
                         plot.



ADVANCED COMMANDS                                                 Page 10-2


     %CLSPLT/qualifiers


               Closes the plot by putting the terminal out of graphics mode
          and  restoring  /QUIET  or /NOQUIET, whichever was in effect when
          the %OPNPLT command was issued.

            Valid qualifiers are:

            /[NO]WAIT    Controls whether PPLUS pauses after plot 
                         completion.  Pause is signaled by a tone
                         and terminated by typing a character. If
                         an <ESC> is typed PPLUS will return from
                         the current command level to the lowest
                         command level.  Default = WAIT.

     %PLTLIN,n


               Plots the n-th data line.  Each RD  command  increments  the
          data  line  count  by  1.   Use of the standard plotting commands
          (PLOT, PLOTUV, PLOTV, CONTOUR, VECTOR, and VIEW) resets the  data
          line  count.   The  %PLTLIN  command does not reset the data line
          count.  (WINDOW works.)

                      n          Plot line n using current 
                                 scale factors.

     %LABEL/qualifier,x,y,ipos,ang,chsiz,label


               Draws a label similar to a moveable  label  (LABS  command).
          There  is  no  label number and the label is drawn as soon as the
          command is read from the command file.  Any number of labels  may
          be drawn.

                      x          x position user or inches
                      y          y position user or inches
                      ipos       -1 left, 0 center, +1 right 
                                 justify
                      ang        Angle at which lable is to
                                 to be drawn.  (0 degrees is 
                                 at 3 o'clock and positive 
                                 rotation is counter 
                                 clockwise.)
                      chsize     character size (inches)
                      label      character string to draw

            Valid qualifiers are:

            /[NO]USER   determines units of x and y positions.  Default
                        is /USER. If /NOUSER units are inches from the 
                        ORIGIN.  (see the ORIGIN command)



ADVANCED COMMANDS                                                 Page 10-3


     %RANGE,min,max,ntic


               Finds axis  limits  for  use  with  the  %XAXIS  and  %YAXIS
          commands  given the data extrema of min and max.  The axis limits
          and tic interval are returned in the PPLUS symbols PPL$RANGE_LOW,
          PPL$RANGE_HIGH, and PPL$RANGE_INC.

                      min        minimum value of data to be ranged
                                 Can use PPL$XMIN(n) or PPL$YMIN(n).
                      max        maximum value of data
                                 Can use PPL$XMAX(n) or PPL$YMAX(n).
                      ntic       number of large increments

            PPL$RANGE_LOW        new minimum range value
            PPL$RANGE_HIGH       new maximum range value
            PPL$RANGE_INC        new increment

     %XAXIS/qualifier,xlow,xhigh,xtic,y[,nmstc][,lint]
          [,xunit][,ipos][,csize][,frmt] 


               This command draws an x-axis and redefines scaling  for  the
          x-direction.  The arguments xlow, xhigh, xtic and y should not be
          omitted.  See the %RANGE command to get default values  for  axis
          limits and increments.  If you have used %RANGE, then you can use
          PPL$RANGE_LOW, PPL$RANGE_HIGH, PPL$RANGE_INC for xlow, xhigh  and
          xtic.

                      xlow       min value of x user
                      xhigh      max value of x user
                      xtic       large tic increment user
                      y          y position user or inches
                      nmstc      number of small tics
                      lint       label interval (large tics)
                      xunit      divisor for axis label
                      ipos       -1 bottom, 0 none, +1 top of label
                      csize      character size inches
                      frmt       axis format char*20

            Valid qualifiers are:

            /[NO]USER   determines units of y position.  Default
                        is /USER. If /NOUSER units are inches from the 
                        ORIGIN.  (see the ORIGIN command)

     %YAXIS/qualifier,ylow,yhigh,ytic,x[,nmstc][,lint]
          [,yunit][,ipos][,csize][,frmt] 


               This command draws an y-axis and redefines scaling for the y
          direction.   The  arguments ylow, yhigh, ytic and x should not be
          omitted.  See the %RANGE command to get default values  for  axis



ADVANCED COMMANDS                                                 Page 10-4


          limits and increments.  If you have used %RANGE, then you can use
          PPL$RANGE_LOW, PPL$RANGE_HIGH, PPL$RANGE_INC for ylow, yhigh  and
          ytic.

                      ylow       min value of y user
                      yhigh      max value of y user
                      ytic       large tic increment user
                      x          x position user or inches
                      nmstc      number of small tics
                      lint       label interval (large tics)
                      yunit      divisor for axis label
                      ipos       -1 left, 0 none, +1 right of label
                      csize      character size inches
                      frmt       axis format char*20

            Valid qualifiers are:

            /[NO]USER   determines units of y position.  Default
                        is /USER. If /NOUSER units are inches from the 
                        ORIGIN.  (see the ORIGIN command)


          EXAMPLE:

               Here is a PPLUS command file which uses all the  %  routines
          described  above.   It can be found in the directory ppl$examples
          (PPL$EXAMPLES:CTD4.PPC), and can be executed in PPLUS to generate
          a plot.

          c
          c  PPLUS command file to plot EPIC CTD data demonstrating
          multiple axis 
          c  capability.
          c
          c  It plots  Pressure vs Temperature, Salinity, Sigma_t, Oxygen.
          c
          box,off
          window,on
          size,8,10.5
          origin,,2.3
          format/ctd,epic
          axlint,1,1
          c pltnme,ctd4.plt
          c
          c  First plot P vs T with T axis at top.  Supress bottom x axis.
          c
          evar,t,p
          rd,ppl$examples:ctd4
          %opnplt
          %range/nouser 'ppl$ymin(1)','ppl$ymax(1)',5
          yfor,(i7)
          yaxis,'ppl$range_high','ppl$range_low','ppl$range_inc'
          title



ADVANCED COMMANDS                                                 Page 10-5


          axlabp,1
          axset,,0
          plot
          c
          c  Plot P vs Salinity with S axis at top above T axis.
          c
          evar/next sal,p
          rd
          set ypos 'ppl$ylen' + .7
          %range/nouser 'ppl$xmin(1)','ppl$xmax(1)',4
          %xaxis/nouser,'ppl$range_low','ppl$range_high','ppl$range_inc',-
          'ypos',,,,+1
          %pltlin,1
          c
          c  Plot P vs Sigma_t with S_t axis at bottom
          c
          evar/next sig,p
          rd
          set ypos 0.
          %range/nouser 'ppl$xmin(2)','ppl$xmax(2)',4
          %xaxis/nouser,'ppl$range_low','ppl$range_high','ppl$range_inc',-
          'ypos',,,,-1
          %pltlin 2
          c
          c  Plot P vs Oxygen with O axis at bottom below S_t axis.
          c
          evar/next ox,p
          rd
          set ypos 'YPOS' - .7
          %range/nouser 'ppl$xmin(3)','ppl$xmax(3)',4
          %xaxis/nouser,'ppl$range_low','ppl$range_high','ppl$range_inc',-
          'ypos',,,,-1
          %pltlin 3
          c
          c  Now use PPLUS EPIC symbols in moveable labels for graph titles
          c
          set ypost 'ppl$ylen' + 1.9
          %label/nouser 0,'ypost',-1,0.,.16,'ppl$epic_latitude1'
          'ppl$epic_longitude1'
          set ypos 'ypost' + .3
          %label/nouser 0,'ypos',-1,0.,.16,'ppl$epic_cast1'
          'ppl$epic_date1'
          %clsplt














                                CHAPTER 11

                         PLOT5, PPLUS DIFFERENCES




               PPLUS is a greatly  enhanced  replacement  to  PLOT5.   Most
          PLOT5 syntax and commands are identical to PPLUS usage.  However,
          there are the following differences and incompatabilities.

               RDCOM command has been replaced by the @ command.

               The LEV command replaces the LEVEL and CLINE commands.

               In format statements and labels single quotes  (')  must  be
          replaced  by  two single quotes ('').  The same applies to double
          quotes (").  See the chapter on labels.

               The LIMITS command is enhanced.

               IF / ELSE / ENDIF and WHILE / ENDW logic  are  available  in
          command  files.   The  INC  and  DEC  commands  are  available to
          increment and decrement symbols.

               The TXLINT,  TXLABP,  TXLSZE,  TXNMTC  and  TXTYPE  commands
          should  be  used  instead of using the corresponding arguments in
          the TAXIS command.

               The TIME command should be used instead of  the  TMIN,  TMAX
          and TSTART commands.

               NOTE :  The following commands are not supported in this and
          future versions of PPLUS:

               TMIN, TMAX and TSTART

               LEVEL and CLINE

               RWDSEQ, READSEQ and SKPSEQ

               TAXIS will not support the obsolete arguments.














                                CHAPTER 12

                            COMMAND DESCRIPTION





     @file_name/qualifier arg1 arg2 arg3 ...

               Reads commands from the file file_name  until  an  EOF,
          blank  line,  a RETURN command is executed or the file ends,
          then reverts  to  the  previous  command  level  for  input.
          Default  device  is  SY:.  Default extension is '.PPC'.  The
          current  command  file  name  is  placed  in  global  symbol
          PPL$COMMAND_FILE.

               PPLUS can be started with a command file  specified  by
          typing  $PPL  file_name, where file_name is the command file
          name.  PPLUS will produce no screen output if called from  a
          BATCH  file.  PPLUS will terminate and not pass control back
          to the SYS$INPUT file.

               The arguments may be any legal string.   The  arguments
          arg1,arg2,etc are SET to the local symbols P1, P2, etc.  For
          example:

            @command_file your_file "A label" "PLTYPE 2"

           The local symbols will be:

            P1 = your_file
            P2 = A label
            P3 = PLTYPE 2

               These symbols can then be substituted into the  command
          file.

               Qualifiers are (default in parenthesis):

            /[NO]ECHO    Controls echoing to the file echo.dat 
                         during execution. (NOECHO)

            /[NO]DEBUG   Sets DEBUG mode during execution.  In



COMMAND DESCRIPTION                                          Page 12-2


                         debug mode the commands are written to the
                         echo file after symbol substitution has
                         occurred. (NODEBUG)

            /[NO]QUIET   Turns off messages to the terminal. (NOQUIET)

            /[NO]LOG     Echos commands to terminal. (NOLOG)

            /[NO]LATCH   Causes the current qualifiers to be the
                         new default for all command levels. (NOLATCH)


     AUTO,ON/OFF

               Turns on and off the automatic copying of  plots  while
          at a TEK terminal.    default=OFF


     AUTOLAB,ON/OFF

               ON (default for BIBO and EPIC data) to get graph labels
          from  data  file  headers.   OFF  (default  for  other  data
          formats) for manual entry of graph labels.    default=OFF


     AXATIC,ATICX,ATICY

               Sets the number of large tics in auto mode for X and  Y
          axes.    default=5


     AXLABP,LABX,LABY

               Sets the numeric and character label position for X and
          Y axes.  -1=bottom/left of plot, 0=no label, +1=top/right of
          plot.    default=-1


     AXLEN,XLEN,YLEN

               Sets the X and Y axes length in inches.  XLEN  is  also
          used   as   the   length   in   inches  of  the  time  axis.
            default=5.5,4.0 The values of xlen and ylen are placed  in
          global symbols PPL$XLEN and PPL$YLEN.


     AXLINT,LINTX,LINTY

               Sets the label interval for X and Y axes.   Labels  are
          only  drawn  for large tics.    Default=2, i.e.  every other
          large tic.



COMMAND DESCRIPTION                                          Page 12-3


     AXLSZE,HGTX,HGTY

               Sets the label height for  X  and  Y  axes  in  inches.
          default=0.10  If  HGTX  or HGTY is negative the numeric axis
          labels are multiplied by -1 before plotting.


     AXNMTC,NMTCX,NMTCY

               Sets the number of small tics between large tics for  X
          and Y axes.    default=0


     AXNSIG,NSIGX,NSIGY

               Sets the number of significant  digits  in  labels  for
          auto labelling.    default=2


     AXSET,TOP,BOT,LEFT,RIGHT

               Sets the flags controlling the  plotting  of  the  four
          axes.   If  =1  axis is ON, =0 axis is OFF.  The default for
          all axes is ON.


     AXTYPE,TYPEX,TYPEY

               Sets the axis type for X and Y axes.  1 - normal,  2  -
          log,  3  -  inv-log.   Type  3 axis draws the top/right axis
          inverse and the bottom/left normal.    default=1


     BAUD,IB

               Sets baud rate.  Null entry not allowed.

               IB= Baud rate   default=110


     BOX,ON/OFF

               Turns on and off the  box  that  is  drawn  around  the
          entire plotting region.  default is ON.


     C

               Comment.  This command can be used to  comment  your  @
          files.   No  action  is done when this command is processed.
          The C must be followed by at least one blank space.



COMMAND DESCRIPTION                                          Page 12-4


     CLSPLT Closes  the  metacode  file.   Not  to  be  confused  with
          %CLSPLT,  which  is  documented  in  the  Advanced  Commands
          Chapter.


     CONPRE,prefix

               Sets a prefix string for the numeric contour labels  of
          up  to  10 characters.  For example, CONPRE,@P2@TR will give
          labels using pen  2  and  triplex  roman  font.   Default  =
          spaces.


     CONPST,postfix

               As CONPRE but sets up to 10  characters  following  the
          contour numeric label.  For example, CONPST,cm/sec will give
          contour labels like "10 cm/sec".  Default = spaces.


     CONSET,HGT,NSIG,NARC,DASHLN,SPACLN,CAY,NRNG,DSLAB

               Sets parameters for contouring and placing random  data
          on a grid.  Must be issued before the RD command.

          HGT = height of contour labels   default=.08 inches
          NSIG = no. of significant digits in contour labels 
                 default=2
          NARC = number of line segments to use to connect contour 
                 points   default=1
          DASHLN = dash length of dashes mode   default=.04 inches
          SPACLN = space length of dashes mode   default=.04 inches
          CAY = is the interpolation scheme.  If CAY=0.0, Laplacian 
                interpolation is used.  The resulting surface tends
                to have rather sharp peaks and dips at the data 
                points (like a tent with poles pushed up into it).
                There is no chance of spurious peaks appearing.  As
                CAY is increased, Spline interpolation predominates
                over the Laplacian, and the surface passes through
                the data points more smoothly.  The possibility of
                spurious peaks increases with CAY.  CAY= infinity is
                pure Spline interpolation.  An over relaxation 
                process in used to perform the interpolation.  A 
                value of CAY=5.0 (the default) often gives a good 
                surface.
          NRNG = Any grid points farther than NRNG away from the 
                 nearest data point will be set to "undefined" 
                 (1.0E35).   default=5
          DSLAB= nominal distance between labels on a contour line.
                 default = 5.0 inches


     CONTOUR/qualifier,vcomp,label



COMMAND DESCRIPTION                                          Page 12-5


               Does a contour plot of  data  in  buffer.   Label  will
          replace  that  in  the  current main label buffer.  Label is
          optional.  If either axis is log that index must be  equally
          spaced in log-space (i.e.  10**(xmin+dx)).  Contour does not
          take the log of the coordinate.  The contour lines  will  be
          plotted  with the pen selected for line 1.  The label cannot
          begin with a numeric character, i.e., 95W.  You can  plot  a
          number by specifying a font, e.g., @SR100 meters.

               Vcomp indicates  which  vector  component  to  contour.
          Default  is  1.  Vcomp is to be used when a vector field has
          been read in.  See the VECSET and VECTOR commands.

               Valid qualifiers are:

            /[NO]WAIT    Controls whether PPLUS pauses after plot 
                         completion.  Pause is signaled by a tone
                         and terminated by typing a character. If
                         an <ESC> is typed PPLUS will return from
                         the current command level to the lowest
                         command level.  Default = WAIT.

            /[NO]OVERLAY Controls whether PPLUS overlays the
                         plot on the preceeding plot. The default
                         is /NOOVERLAY which causes the plot
                         to be a new plot.  The axes and their 
                         labels are not redrawn.  Moveable labels
                         (LABS command) will redraw.


     CROSS,ICODE

               Turns on and off the drawing of a  solid  line  through
          (0,0)   on   a  plot.   Optionally  can  draw  vertical  and
          horizontal  lines.   Draws  line  through  (XOFF,YOFF)  when
          either   TRANSXY   or  LINE  command  is  used  to  apply  a
          transformation to the data.

           ICODE = 0 cross off
                 = 1 draw through (0,0) (default)
                 = 2 horizontal line through each YOFF
                 = 3 vertical line through each XOFF
                 = 4 horizontal and vertical through each XOFF, YOFF


     DATPT,type,mark

               Controls the drawing of marks on a contour  plot  along
          the  x  and/or  y axis on a grid at the points where the raw
          ungridded X,Y,Z triplets are located.

          type = 0 no points drawn (default)
               = 1 points drawn along the x axis



COMMAND DESCRIPTION                                          Page 12-6


               = 2 points drawn along the y axis
               = 3 points drawn at each raw input value
          mark = 0 use the default mark (default)
               = other use the specified mark to denote the location.

               The default mark is down arrow for x axis,  left  arrow
          for y axis, and pluses for type=3.  (also see MARKH)


     DEBUG on/off

               Turns on and off the debugging mode.  In debug mode the
          input  lines  are  echoed  to the ECHO.DAT file after symbol
          substitution.  Default = off.


     DEC symbol

               Decrements the value  stored  in  symbol  by  one.   If
          symbol  does  not  exist  it is created and given a value of
          zero.


     DELETE symbol

               Deletes "symbol" from the symbol table.


     DFLTFNT,font

               Sets the default font used for  all  labelling.   PPLUS
          initially  uses  Simplex  Roman  (SR)  as  the default font.
          Fonts are still selectable using the font command @xx, where
          xx  is  the  two letter font code.  NOTE:  This command also
          replaces the string set  by  the  CONPRE  command  with  the
          selected  font.  The default font is not saved with MULTPLT.
          This command changes the environment and can only be changed
          back with another DFLTFNT command or using the @CL command.

          font = the new default font (no default)


     DIR,arg

               Prints a listing of files with names or extensions that
          match "arg".


     ECHO,on/off

               Turns on/off echoing of PPLUS commands in the echo file
          ECHO.  Default is ON.  ECHO is a logical that can be defined
          prior to entering PPLUS (e.g., DEFINE ECHO  echo_file.echo).



COMMAND DESCRIPTION                                          Page 12-7


          Default is for echoing to go into the file ECHO.DAT.


     ENGLISH

               Sets the internal  conversion  factors  in  COMPLOT  to
          inches.   This  is  the  default condition.  (see the METRIC
          command)


     ENTER

               Allows the input of X,Y pairs from the terminal.  PPLUS
          prompts the user with 'enter>'.  Type END to stop.


     EVAR/qualifier,x-var,y-var

               Specifies which EPIC variables are to be plotted  as  x
          and   y  when  FORMAT,EPIC  command  has  been  given.   The
          EPIC/pointer file is named with the  RD  command,  and  each
          call  to  RD  results  in  reading another EPIC data file as
          indicated by the EPIC/pointer file.  PPLUS can extract  axis
          labels  and  a  plot  title from the data file headers.  Use
          FORMAT/CTD,EPIC to tell PPLUS that EPIC CTD  data  is  being
          read.   Use  FORMAT,EPIC to tell PPLUS that EPIC time series
          data is being read.  See FORMAT command description for  all
          the EPIC defaults.

          x-var = Variable to be plotted as x
          y-var = Variable to be plotted as y

          EVAR ? displays a list of variables possible for x-var and
          y-var.

          Examples of variables are TIM (time), U (zonal velocity),  V
          (meridional  velocity), etc.  If you want to plot x=time and
          y=zonal velocity, the command would be EVAR,TIM,U.   If  the
          variable  you  want  to  plot  is  not in this list, you can
          specify the column number of the variable in the  EPIC  data
          file.   For example, EPIC current meter data files generally
          have  variables  DATE,TIME,U,V,SPEED,DIRECTION.    To   plot
          x=time and y=speed, the command would be EVAR,TIM,5.  If the
          x variable is specified by column number, the EVAR  argument
          list  must  be  enclosed in double quotes, (e.g., EVAR,"3,4"
          will plot the variable in column 3 as x and the variable  in
          column 4 as y).

          EVAR (without arguments) will yield a plot with  x=date/time
          and  y=the  first  variable  following date/time on the data
          file for time series data.   For  CTD  data,  EVAR  (without
          arguments) will yield a plot with x=variable in column 2 and
          y=variable in column 1 (usually pressure).



COMMAND DESCRIPTION                                          Page 12-8


          Valid Qualifiers are:

            /[NO]OFFSET  For time series data.
                         Controls whether PPLUS offsets the time
                         word so that data points are plotted in
                         the center of each time interval.  The
                         default is OFFSET, which is appropriate
                         for most EPIC time series.  (EPIC time
                         words represent the start of the time
                         interval in most cases, such as average
                         data.)  Use /NOOFFSET to force PPLUS 
                         to plot data points at the start of 
                         each time interval (e.g., this would 
                         be appropriate for subsampled data).
                         Default is OFFSET.

            /[NO]TIME    For time series data.
                         Controls whether PPLUS reads the time
                         word from the time series data file.  
                         The default is /NOTIME, which means 
                         that the data is evenly spaced in time, 
                         making it unnecessary to read the time 
                         words. Use /TIME to make PPLUS read the 
                         time word for data which is unevenly 
                         spaced in time.  Default is /NOTIME
                         (unless dt is negative, in which case
                         the default is /TIME).

            /[NO]NEXT    /NEXT indicates that the next variable
                         is to be read from the same data file.
                         When /NEXT is used, no new data file
                         name will be read from the EPIC file.
                         The variables indicated by the EVAR 
                         command will be read from the last data
                         file.  This option permits overplotting
                         several variables from the same data
                         file, and can be used with the commands
                         described in the ADVANCED COMMANDS
                         chapter to produce a plot with multiple
                         axes.  When /NEXT is used, both x and
                         y variables must be specified with the
                         EVAR command.  Default is /NONEXT.

               The above qualifiers  will  also  work  with  the  VARS
          command when EPIC data is being read.


     EXIT

               Causes all output buffers to be flushed and  exits  the
          program.



COMMAND DESCRIPTION                                          Page 12-9


     FORMAT/qualifier,frmt

               Allows  the  input  of  a  user  supplied  format   for
          formatted sequential data files.  Null entry is not allowed.
          The current format is in global symbol PPL$FORMAT.

          frmt = a format   default=(3F10.2)
                 FREE for free form
                 DSF for DSF files
                 BIBO for DSF files without a PPLUS header
                 EPIC for EPIC time series data
                 UNF for UNFORMATTED files.

            Valid qualifier (for EPIC data only) is:

            /[NO]CTD     Controls whether EPIC data is read as
                         time series data or as CTD data.
                         If the data is EPIC CTD data, then
                         the /CTD switch must be used.  
                         Default is /NOCTD.  


     GET,file_name

               Restores  options  to  those  in  effect  at  the  time
          SAVE,file_name was called.  file_name must be specified.


     GRID[,LINEAR]

               If the argument LINEAR  is  omitted  (default),  normal
          gridding   is  used.   Otherwise,  if  LINEAR  is  included,
          gridding is done by linear interpolation with the  following
          restrictions on the data:

            1. Data must be on a grid.  The grid may have irregular 
               spacing.
            2. There cannot be gaps in the middle of the grid.  Every
               grid point in the middle of the grid must be specified.
            3. The grid may have ragged edges.

               Must be issued before the RD command.  Note that if the
          grid  is  coarser than the data, it is possible that some of
          the data will not be used in the gridding  process.   It  is
          best  to  make  the  grid  as fine as or finer than the data
          rather than coarser.


     HELP,arg

               Give access to the VMS help files on topic "arg".



COMMAND DESCRIPTION                                         Page 12-10


     HLABS,n,height

               Sets the height in inches of the  nth  moveable  label.
          The  height is reset to the default (specified by the LABSET
          command) by omitting the height value or clearing the labels
          with a LABS command.  (also see LABS, RLABS, LLABS, LABSET)


     HLP,arg

               Gives help on the PPLUS topic "arg".


     IF expression THEN

               The first element of a BLOCK IF  statement;  the  other
          two  elements  are  ELSE  and ENDIF.  ELSE and ENDIF are not
          valid in any other context.
          expression = argument operator argument
            argument = symbol name, number or a string enclosed by
          quotes
            operator = .EQ., .NE., .LT., .GT., .LE. or .GE.

               The symbol name can be undefined and its value is  then
          "" (i.e., null string).


     INC sym

               Increments the value stored in the symbol sym  by  one.
          If  sym  does  not  exist it is created and given a value of
          one.


     LABS/qualifier,n,X,Y,JST,label

               Defines the nth movable  label  for  all  plots.   When
          plotting is done, the cross hairs will come on if no X and Y
          position has been specified.  Typing a  C  will  center  the
          label  at  the  cross  hairs or typing a R will position the
          label to the right of the cross hairs.  By  typing  L  or  F
          then  repositioning  the cross hairs and then typing another
          character a line will be drawn from the first point  to  the
          second and the label will be drawn at the second point (if F
          was specified an arrow will be drawn).  Any character  other
          than  L,  F,  R or C will cause the the label to be drawn at
          the cross hairs.  Null entries are  not  allowed  for  n  or
          label.   A  comment  will be inserted into the ECHO.DAT file
          giving the coordinates when cross hairs are used.  If  n  is
          omitted  LABS  is reset and all moveable labels are cleared.
          (also see LABSET, HLABS, RLABS, LLABS)

          n = label number (up to 25 allowed)



COMMAND DESCRIPTION                                         Page 12-11


          X = X position of label in user units (optional)
          Y = Y position of label in user units (must exist if X is 
                present)
          JST = justification of label. -1 left (default), 0 center, 
                +1 right
          label = any SYMBEL compatible string

          /[NO]USER   determines units of x and y positions.  Default
                      is /USER. If /NOUSER units are inches from the 
                      ORIGIN.  (see the ORIGIN command)

               NOTE:  Units specified by the /user qualifier are  also
          used  in  the LLABS command.  If your terminal does not have
          cross hairs, you must specify X and Y.


     LABSET,HLAB1,HXLAB,HYLAB,HLABS

               Sets character heights for  labels.   (also  see  LABS,
          RLABS, LLABS)
          HLAB1 = main label    default=.16 inches
          HXLAB = x - label    default=.12 inches
          HYLAB = y - label   default=.12 inches
          HLABS = movable labels   default=.12 inches


     LEV,arg,arg,arg ...

               Sets the contour levels, the  contour  line  type,  the
          contour  line  label  characteristics and lets the user edit
          (insert/delete)  levels.   Any  duplicate  levels  will   be
          deleted, however, each LEV command edits the existing levels
          and unless requested the levels are  not  cleared.   Maximum
          number of levels is 500.

          arg = ()  clear levels, number of automatic levels to 10.
          arg = (min,max,inc,idig)  specifies the contour levels and 
                label type
                  min = starting value for levels creation
                  max = ending value for levels creation (if omitted
                        only the starting level will be created)
                  inc = increment used to create levels. (if omitted
                        only the starting and ending levels will be 
                        created, if 0 the starting and ending levels 
                        are deleted)
                  idig = 0 through 9  Number of digits after the 
                         decimal point in the label
                       = -1 contour label plotted as an integer
                       = -3 no contour label will be drawn
          arg = type(min,max,inc,ipen)  sets the contour lines 
                specified to "type"
                  type = DASH sets the line type to dash
                       = DARK sets the line type to dark (heavy)



COMMAND DESCRIPTION                                         Page 12-12


                       = DEL deletes the indicated levels.
                       = LINE sets the line type to line (normal)
                       = PEN sets the pen used for a contour line to 
                             "ipen".  ipen=0 to use default pen.

               For  example,  "LEV,(),(9,20,1,-1),DASH(8,20,2)"   will
          clear  the  previous  levels  and  create  contours at every
          integral value from  9  to  20  with  the  labels  drawn  as
          integers,  all  even  valued  contours  from 8 to 20 will be
          drawn with dashed lines.


     LIMITS,value,comparison,flag

               This command sets the testing value and  type  of  test
          for  bad  data points.  X, y and z are checked and the point
          will not be plotted if the test is true.

          value = test value for the test
          comparison = XLE test for x .le. value, default off, 0.0
                       XEQ test for x .eq. value, default off, 0.0
                       XGE test for x .ge. value, default on, 1.E35
                       YLE test for y .le. value, default off, 0.0
                       YEQ test for y .eq. value, default off, 0.0
                       YGE test for y .ge. value, default on, 1.E35
                       ZLE test for z .le. value, default off, 0.0
                       ZEQ test for z .eq. value, default off, 0.0
                       ZGE test for z .ge. value, default on, 1.E35
          flag = OFF the test is disabled, otherwise the test is
                     enabled.

               If your are reading data to be  contoured  with  ZGRID,
          the limits are checked only after interpolation.  If you are
          using GRID,LINEAR,  limits  are  checked  before  and  after
          interpolation.


     LINE,n,MARK,TYPE,XOFF,YOFF,DN1,UP1,DN2,UP2

               Sets the characteristics for each of  the  50  possible
          X-Y plot lines.

          n = line number
          MARK = data mark (see list at end of manual, e.g. 1 for x, 3
          for +)
          TYPE = type of line
                  0 - line connecting points and no mark at each point
                  1 - line connecting points and mark at each data
          point
                  2 - mark end points only
                  3 - only mark (no line)
                  4 - dashes
                  5 - dashes with mark at end points



COMMAND DESCRIPTION                                         Page 12-13


          XOFF = X offset   default=0.0
          YOFF = Y offset   default=0.0
          DN,UP = dash characteristics in inches.

               Default TYPE=0 for n=1, TYPE=4 otherwise.


     LINFIT,n,XIMIN,XIMAX,XOMIN,XOMAX

               A linear least squares fit is performed on the data  in
          line  n and the resulting fitting line is placed in the next
          available       line       buffer.        For       example,
          RD,data.fil   LINFIT,1    will  place  the fitting line from
          the regression of line 1 into buffer 2.

          n = line number (no default)
          XIMIN = min x value for the regression domain
          XIMAX = max x value for the regression domain
          XOMIN = min x value for the fitting line (default=XIMIN)
          XOMAX = max x value for the fitting line (default=XOMIN)


               XIMIN and XIMAX default to the minimum and the  maximum
          of  the  data.   XOMIN and XOMAX default to XIMIN and XIMAX,
          respectively.  An alternate form for the command may be used
          when TAXIS is ON and TSTART has been set.  It is:

          LINFIT,n,TIMIN,TIMAX,TOMIN,TOMAX

               Where the arguments are the beginning and ending  times
          in  Woods  Hole  format  WYYMMDDHHMM,  i.e.,  W8101121800 is
          12-JAN-1981 18:00.  The arguments have the same meanings and
          defaults as above.

               The following global symbols are defined by LINFIT:
          PPL$LF_R2 = regression coefficient squared
          PPL$LF_A  = constant for fit  (y = a + b*x)
          PPL$LF_A_STDEV = standard error of A
          PPL$LF_B  = constant for fit
          PPL$LF_B_STDEV = standard error of B
          PPL$LF_VAR = total variance
          PPL$LF_RES_VAR = residual variance after fit


     LIST,IMIN,IMAX,JMIN,JMAX,VCOMP,arg

               List on the terminal the appropriate information.  Null
          entry  is not allowed if arg is not DATA.  IMIN, IMAX, JMIN,
          JMAX only valid if arg=DATA.   Defaults  are  to  print  the
          total plot buffer.

          IMIN=   min I for CONTOUR , start pt for X-Y
          IMAX=   max I for CONTOUR , stop pt for X-Y



COMMAND DESCRIPTION                                         Page 12-14


          JMIN=   min J for CONTOUR , start line  for X-Y
          JMAX=   max J for CONTOUR , stop line  for X-Y
          VCOMP=  vector component to be listed (VECTOR command)
          arg=    LEVELS    contour levels and weights
                  CONSET    contour information
                  DATA      data currently in buffer
                  DATPT   contour data location before gridding
                  LABELS  prints the labels at the terminal
                  LABSET  LABSET parameters
                  LINES   current LINE and PEN values
                  LIMITS  the current values set/reset by the limits 
                          command
                  PLOT    gives plot information and plot file name
                  READ    sequential read information
                  STATS   min and max plus sizes of last read
                  TAXIS   T-axis attributes
                  TICS    Tic sizes and options
                  TRANSXY X and Y transform values
                  VECTOR  Vector plotting attributes (VECTOR command)
                  XAXIS   X-axis attributes
                  YAXIS   Y-axis attributes


     LISTSYM

               Lists the symbols currently defined.


     LLABS,n,X,Y,TYPE

               Defines the starting position in user units for a  line
          associated with the moveable labels.  The end of the line is
          determined from the  LABS  command.   This  command  has  no
          effect   if   the   label  is  to  be  positioned  with  the
          cross-hairs.  If the command is issued  without  coordinates
          the  TYPE  is  set  to none.  Fancy has an arrow head at the
          starting position.  (also see LABS, RLABS, HLABS, LABSET)


          n = label number less than 11
          X = X position of line in user units
          Y = Y position of line in user units
          TYPE = line type.  0 no line, 1 normal line, 2 fancy line

               NOTE:  Units of x and y positions are determined by the
          /USER qualifier in the LABS command.


     MARKH,n,SIZE

               Sets the mark size used for  plotting  line  number  n.
          The  mark size for line 1 is used for the marks in the DATPT
          command (contouring).



COMMAND DESCRIPTION                                         Page 12-15


          n = line number (no default)
          SIZE = size of mark in inches (default= 0.08)


     METRIC

               Sets the internal  conversion  factors  in  COMPLOT  to
          millimeters.  Default condition is inches.


     MULTPLT,NX,NY

               This command allows the  user  to  plot  several  plots
          together.   The  individual  plots  are arranged in rows and
          columns.  The X axis length of each plot in the same  column
          and  the  Y  axis  length  of  each plot in the same row are
          identical.  The axis  lengths  are  specified  in  rows  and
          columns.  The spacings between the rows and columns are also
          user controlled.  If the  spacing  is  zero  the  plots  are
          placed  together  without axis labels if appropriate.  There
          are prompts for all additional information needed.


          NX = number of columns 
          NY = number of rows

          The prompts will be:

          ENTER XLEN FOR COLS 1,2,...,NX
          multplt>
          ENTER YLEN FOR ROWS 1,2,...,NY
          multplt>
          ENTER PLOT SPACINGS
          LEFT BNDRY TO COL1, COL1 TO COL2,ETC...
          multplt>
          ROW1 TO ROW2,...,ROW NY TO BOTTOM
          multplt>



               Axis length and ORIGIN  are  reset  after  plotting  is
          finished.


     NLINES

               Resets the the input buffer so that the next data  line
          read  will  be  line  1.  The input buffer is normally reset
          when a plot is made.


     ORIGIN,XORG,YORG



COMMAND DESCRIPTION                                         Page 12-16


               Sets the distance the lower left  hand  corner  of  the
          plotting area is from the lower left corner of the box.  The
          values of xorg and yorg are placed  in  the  global  symbols
          PPL$XORG and PPL$YORG.

          XORG = x-distance (in)   default=1.4
          YORG = y-distance (in)   default=1.2 


     PEN,n,ipen

               Sets the pen to be used for line n.  ipen should be  in
          the  range  1-6,  subject to the limitations of the plotting
          device.  On the VERSATEC, pen 2 is thicker than pen 1, pen 3
          is  thicker  than  pen  4, etc.  The pen selected for line 1
          will be used to draw the contour lines.  (also see LEV)

          n = line number. If n=0 sets the pen used to plot the axes 
              and labels.
          ipen = pen number.   default=1


     PLOT/qualifiers,label

               Does an X-Y plot  of  data  in  the  plot  buffer  (all
          lines).  The plot label "label" is optional.  The plot label
          can be blanked with the TITLE command.  If either x-axis  or
          y-axis   is   log  PLOT  will  take  the  logarithm  of  the
          appropriate coordinate as it  is  plotted.   This  will  not
          affect the data buffer.

               Valid qualifiers are:

            /[NO]WAIT    Controls whether PPLUS pauses after plot 
                         completion.  Pause is signaled by a tone
                         and terminated by typing a character. If
                         an <ESC> is typed PPLUS will return from
                         the current command level to the lowest
                         command level.  Default = WAIT.

            /[NO]OVERLAY Controls whether PPLUS overlays the
                         plot on the preceeding plot. The default
                         is /NOOVERLAY which causes the plot
                         to be a new plot.  The axes and their 
                         labels are not redrawn.  Moveable labels
                         (LABS command) will redraw.


     PLOTV/qualifiers,VANG,INC,label

               Does  a  stick  plot  for  U,V  pairs  stored  in   X,Y
          ,respectively.  May be used with or without TAXIS option ON.



COMMAND DESCRIPTION                                         Page 12-17


          VANG = rotation angle of vectors   default=0.0
          INC = plots every inc vector (subsamples)
          label = plot label 

               Valid qualifiers are:

            /[NO]WAIT   Controls whether PPLUS pauses after plot 
                         completion.  Pause is signaled by a tone
                         and terminated by typing a character. If
                         an <ESC> is typed PPLUS will return from
                         the current command level to the lowest
                         command level.  Default = WAIT.

            /[NO]OVERLAY Controls whether PPLUS overlays the
                         plot on the preceeding plot. The default
                         is /NOOVERLAY which causes the plot
                         to be a new plot.  The axes and their 
                         labels are not redrawn.  Moveable labels
                         (LABS command) will redraw.


     PLOTUV/qualifiers,VANG,INC,label

               Similar to PLOTV except U and V are in alternate pairs,
          where   X1=  count,  Y1=  U  component,  X2=  count,  Y2=  V
          component, etc.  NLINES must be set to an  even  number  and
          first series read will be U second V etc.

               Valid qualifiers are:

            /[NO]WAIT   Controls whether PPLUS pauses after plot 
                         completion.  Pause is signaled by a tone
                         and terminated by typing a character. If
                         an <ESC> is typed PPLUS will return from
                         the current command level to the lowest
                         command level.  Default = WAIT.

            /[NO]OVERLAY Controls whether PPLUS overlays the
                         plot on the preceeding plot. The default
                         is /NOOVERLAY which causes the plot
                         to be a new plot.  The axes and their 
                         labels are not redrawn.  Moveable labels
                         (LABS command) will redraw.


     PLTNME,fname

               Specifies the file name to be  used  for  plots.   File
          name is available in the global symbol PPL$PLTNME.
          fname = the file name (default = ZETA.PLT)


     PLTYPE,ICODE



COMMAND DESCRIPTION                                         Page 12-18


               Sets plotting medium.  Null entry is not allowed.   The
          binary  file  is converted into device specific code using a
          post processor.  The plot file name can be  specified  using
          the PLTNME command.
           ICODE = device code for plotting
                 -2 = HP and TEK 
                 -1 = HP
                  0 = Binary file
            1 = TEK
            2 = TEK and Binary file
            3 = GKS (valid on MicroVAX only)
            4 = GKS and Binary file (valid on MicroVAX only)
            default=1 


     RD/qualifier,NX,NY,TYPE,n,file_name

               Read formatted or unformatted data  from  a  sequential
          file  according to FORMAT and VARS or EVARS.  The input file
          name is available in the global symbol PPL$INPUT_FILE.

               NX and NY  define  the  grid  on  which  data  will  be
          plotted.   If  X,Y,Z triplets are being read the grid can be
          coarser or finer than the input data.   Thus,  when  reading
          triplets  NX,  NY  of  50,  21  indicates  the grid used for
          contouring will be 50 x 21 and not that the input data is on
          this  grid.   When  the  input data are values of Z only the
          input grid and the plotting grid must be identical.  Maximum
          number of points for a single read is 100,000 pairs, 200,000
          grid points or 50,000 triplets.  Default  number  of  points
          read  is  the  remaining  buffer  space.   File_name  may be
          omitted  if  previously  defined.   Null  entries  are   not
          allowed.

          NX = no. of columns on the plotting grid for contouring or
               no. of points to read if not contouring.  See NY for 
               explanation.
          NY = no. of rows if data is on a grid for contouring.  
               Omitted otherwise.

               The meaning of NX and NY change depending on whether 
               you're reading data for contouring or not.  If you're
               reading contour data NX is the number of columns and 
               NY is the number of rows.

               If the data is not contour data NX is the number 
               of points to be read and NY is not required.  The 
               default for NX is the space remaining in the buffer.
               Reading will stop automatically at the EOF without any
               error.
          TYPE = method by which grid data is to be read (contour 
                 data only)
                   0 by rows (1st subscript varies fastest)



COMMAND DESCRIPTION                                         Page 12-19


                   1 by columns (2nd subscript varies fastest)
          N = number of data sets to be read (on same file). 
          file_name = file name.  Default device is SY:.
                If the file name is explicitly given the file will be
                read after rewinding the file.  If the file name is 
                not given no rewind takes place.

                If the data is EPIC, the file name given with the RD
                command is the name of the EPIC/pointer file for the
                data file.  Otherwise, the file name is the name of
                the data file itself


            Valid qualifier (use only with VECTOR, VECSET, VECKEY
          commands):
             /[NO]VECTOR  /VECTOR reads the second component grid
                          using the old xmin,xmax,ymin,ymax.  This
                          is done after the first vector component
                          has been read in the usual fashion.  See
                          the VECTOR command
                          Default is /NOVECTOR.

          If you are reading triplets PPLUS prompts for  total  number
          of  points  to  be  read  in with 'rd>'.  If you are reading
          triplets  or  grid  data  PPLUS   will   also   prompt   for
          xmin,xmax,ymin,ymax.  (limits)


     RESET

               Uses the logical PPL$RESET as the input file to the GET
          command.


     RETURN

               Return from  current  command  level  to  the  previous
          command  level.   If  executed  at  the top level PPLUS will
          exit.


     RLABS,n,ANG

               Specifies the angle  to  rotate  the  moveable  labels.
          (The labels defined by the LABS command.)

          n = number of the label (no default)
          ANG = angle in degrees.  Default = 0.0


     ROTATE,ON/OFF



COMMAND DESCRIPTION                                         Page 12-20


               Rotates the plot 90 degrees on the screen and  plotter.
          Default = OFF


     RWD,file_name

               Rewinds  the  current  data  file.   File_name  may  be
          omitted  if  previously  defined.  Files are also rewound by
          explicitly including  the  file  name  in  the  SKP  and  RD
          commands.   Rewinds  the  EPIC pointer file.  The input file
          name is available in the global symbol PPL$INPUT_FILE.

               If the data is EPIC, the file name given with  the  RWD
          command is the name of the EPIC/pointer file for time series
          data.  Otherwise, the file name is the name of the data file
          itself


     SAVE,file_name

               Saves the options currently in effect on file file_name
          in a binary format.  File_name must be specified.


     SET sym arg

               Creates/modifies the symbol sym and  sets  it  to  arg.
          The  argument  arg can be either a legal character string, a
          simple arithmetic expression,  or  a  special  function.   A
          simple  arithmetic  expression  is of the form num1 op num2,
          where  op  is  +,  -,  *  or   /   (addition,   subtraction,
          multiplication  or  division) and num1 and num2 are numbers.
          The numeric values must be separated from the operator op by
          spaces.   The  string  will be used exactly as it appears if
          enclosed by double quotes (").  For example:

          SET XPOS 4.4 + 2           results in XPOS =  6.200E00
          SET A_LABEL "4.4 + 2"      results in A_LABEL = 4.4 + 2

               The special functions manipulate and reformat character
          strings.  They are:


               $EDIT(symbol,argument)

               $EXTRACT(start,length,symbol)

               $INTEGER(symbol)

               $LENGTH(symbol)



COMMAND DESCRIPTION                                         Page 12-21


               $LOCATE(substring,symbol)

               $ELEMENT(position,delimiter,symbol)

          The general format is  SET  sym  $function(arg1,  arg2,...).
          These  functions  are  described  in  the  SPECIAL FUNCTIONS
          section.


     SHOW symbol

               Prints the current value of "symbol".


     SIZE,width,height

               Sets total plotting size  in  inches  of  the  plotting
          region.  Null entries are not allowed.  The width and height
          should be about 2 and 1.5 inches greater than the respective
          axis  lengths.  The displacement specified by ORIGIN must be
          considered when values for SIZE and AXLEN are being  chosen.
          The  maximum  allowed  size  for Versatec plots (to keep the
          plot on a single page) is 8 by 10.5.  The  values  of  width
          and  height  are  placed in the global symbols PPL$WIDTH and
          PPL$HEIGHT.
           width = plotting area total width  (default = 7.5)
          height = plotting area total height (default = 5.625)


     SKP,n,file_name

               Skip n sequential or  unformatted  records.   File_name
          may  be  omitted if previously defined.  If the file name is
          explicitly given the records will be skipped after rewinding
          the  file.   If  the  file name is not given no rewind takes
          place.  The input file  name  is  available  in  the  global
          symbol PPL$INPUT_FILE.

               If the data is EPIC, the file name given with  the  SKP
          command is the name of the EPIC/pointer file for time series
          data.  Otherwise, the file name is the name of the data file
          itself.


     SMOOTH,n

               Does n laplacian smoothings on contour type data.  Null
          entry is not allowed.


     SPAWN



COMMAND DESCRIPTION                                         Page 12-22


               Creates  a  sub-process  and  passes  control  to  this
          process.  When finished with the spawned process type LOGOUT
          to return to PPLUS.


     TAXIS/qualifier,DT,arg

               Sets the time axis characteristics.  The axis length is
          specified  with  AXLEN  for  this style axis.  When TAXIS is
          turned on and BIBO or EPIC formatted data is read, the  time
          series are automatically adjusted properly relative to TMIN.
          NOTE:  DT and TSTART (set with the TIME command) are  needed
          only when BIBO or EPIC data is not being used.

          DT = sampling rate in minutes (default=1440 ,ie, daily)
          arg = ON/OFF turns TAXIS option on and off (default=OFF)

          /[NO]YAXIS   if yaxis draw a vertical time axis in place 
                       of the yaxis. (NOYAXIS)


     TEKNME[,fname]

               Stores the Tektronix plot in file fname  if  specified.
          Terminal  must  have  NOWRAP  to  dump  the plot back to the
          screen with the TYPE command.  The  current  Tektronix  plot
          file name is available in global symbol PPL$TEKNME.


     TICS,SMX,LGX,SMY,LGY,IX,IY

               Sets the sizes in inches of the small and large tics on
          the  X  and  Y axis.  The tic style may also be set for both
          axis.
          SMX = small X axis tic size   default=0.125
          LGX = large X axis tic size   default=0.25
          SMY = small Y axis tic size   default=0.125
          LGY = large Y axis tic size   default=0.25
          IX =     1   X tics on the inside
                   0   X tics on both sides 
                  -1   X tics on the outside (default)
          IY  =    1   Y tics on the inside
                   0   Y tics on both sides 
                  -1   Y tics on the outside (default)


     TIME,TMIN,TMAX,TSTART

               Specifies time axis limits and starting  time  of  time
          series  data.  See TAXIS command for restrictions.  (Default
          is auto-scaling for BIBO and EPIC formatted data)



COMMAND DESCRIPTION                                         Page 12-23


               Note:  If you  read  time  as  a  sequence  number  and
          specify DT (set with the TAXIS command) and TSTART, then the
          TSTART time/date must correspond to a sequence number of  1.
          TMIN  and  DT  (see  TAXIS command) must be specified before
          TSTART.  TSTART must be re-entered whenever DT is changed.

          TMIN = Start date/time of time axis (WHOI format = 
                 Wyymmddhhmm)
          TMAX = End date/time of time axis
          TSTART = Start time of time series data (optional)


     TITLE,HLAB,label

               Sets the main plot title to "label" without  generating
          a  plot.   If  "label"  is  omitted  the  main plot title is
          cleared.  Optionally the size  of  the  title  can  also  be
          specified.

          HLAB = the height of the title in inches. (default = .16
          inches)


     TKTYPE,TYPE

               Sets the type of  TEK  terminal.   Null  entry  is  not
          allowed.   Valid  values are:  4010, 4014, 4107, 4115, 4051,
          4052 and 4662.

               TYPE = model no.  of TEK terminal   default=4010


     TRANSXY,n,XFACT,XOFF,YFACT,YOFF

               Lets you define a linear transformation for the X and Y
          variables  in  each  line,  i.e.,  XT(i)= XFACT*X(i) + XOFF.
          TRANSXY does not affect the data.  The translation  is  only
          applied as the data is plotted.

          n = line number (no default)
          XFACT = multiplicative factor for X (default=1.0)
          XOFF = offset for X (default=0.0)
          YFACT = multiplicative factor for Y (default=1.0)
          YOFF = offset for Y (default=0.0)

               The transformation factors are available in the  global
          symbols    PPL$XFACT(n),   PPL$XOFF(n),   PPL$YFACT(n)   and
          PPL$YOFF(n), where "n" is the line number.   Initially  only
          the first 10 lines will have these symbols defined.

               If the value being scaled is time and TAXIS is on, XOFF
          or  YOFF  is  in units of DT.  Unless DT is changed with the
          TAXIS command, it will have the default value of 1 day.



COMMAND DESCRIPTION                                         Page 12-24


     TXLABP,n

               Specifies time axis label position (-1 for below  plot,
          0 for no label, or +1 for above plot).


     TXLINT,low_int,hi_int

               Specifies which time axis tics will be labeled.

          Low_int = labeling interval for lowest level of tics 
                    (e.g. mon on mon/yr axis)
          Hi_int = labeling interval for highest level of tics 
                    (e.g. yr on mon/yr axis)


     TXLSZE,ht

               Specifies height of time axis labels (inches).


     TXNMTC,n

               Specifies number of small tics between  large  tics  on
          time  axis.   If NMTCT is -1 the major divisions are denoted
          by large  tics  and  the  minor  divisions  by  small  tics,
          otherwise  they  are  denoted  by thick tics and large tics,
          respectively.


     TXTYPE,type,style

               Specifies type and style of time series axis.
          type = DAYS
                        style = HR (hour,day on 2 lines) (default)
                                HRDAY (on 1 line)

               = MON
                        style = DAY (day,mon on 2 lines) (default)
                                DAYMON (day,mon on 1 line)

               = YR (default)
                        style = MON1 (1-char month)
                                MON3 (3-char month) (default)
                                MONYR (month,yr on 1 line)


     VARS,NGRP,A1,A2,A3,...,Ai

               Defines the location of variables within a record of  a
          sequential   data  file.   If  only  a  single  variable  is
          specified and it is either X or Y the other is automatically
          filled with the data point number.  If only Z (gridded data)



COMMAND DESCRIPTION                                         Page 12-25


          is given the program expects data to be grid points  in  one
          of  two  formats,  by  rows  or  by columns.  If X, Y, and Z
          (triplets) are given the program uses ZGRID to put the  data
          on  a  evenly spaced grid.  See the chapters Getting Started
          and Data Formats for more information on VARS.


          NGRP = no. of groups per record
          Aj = 1,2, or 3 The position of Aj in VARS command indicates
          which variable
               is to be read as an x, y or z.
            1 = X variable
            2 = Y variable
            3 = Z variable
          i = NVAR no.  of variables per group.     default=VARS,1,1,2
          (i.e.   one group per record, first variable is X, second is
          Y).  If left blank indicates a number not to be read, but  a
          variable is present and expected by the FORMAT.


     VECKEY/qualifier,x,y,ipos,format


               VECKEY sets where the scaling key for  the  vectors  is
          plotted.  See VECTOR and VECSET commands.

            x  =  x position of vector key
            y  =  y position of vector key  (default is no key at all)
            ipos = relative position of key  (not implemented)
            format = format to draw the numeric part of the key
                     default = (1pg10.3)

            Valid qualifiers are:

            /[NO]USER   determines units of x and y positions.
                        Default is /USER. If /NOUSER units are 
                        inches from the ORIGIN.  
                        (see the ORIGIN command)


     VECSET,length,scale



               VECSET sets the scaling for the vectors  plotted.   See
          the VECTOR and VECKEY commands.

            length = length of standard vector in inches.
                     this is also the length of the scale vector.
                     Default is 0.5.
            scale  = length of standard vector in user units.
                     This is also the length of the scale vector is
                     user units.  Default is the twice the mean 



COMMAND DESCRIPTION                                         Page 12-26


                     length of the vectors.


     VECTOR/qual,skipx,skipy,label



               VECTOR draws a field  of  vectors  from  two  component
          grids.  See the VECKEY and VECSET commands.

            skipx = plot every skipx column (default is 1)
            skipy = plot every skipy row (default is 1)
            label = title of plot

           Valid qualifiers are:

            /[NO]WAIT    Controls whether PPLUS pauses after plot 
                         completion.  Pause is signaled by a tone
                         and terminated by typing a character. If
                         an <ESC> is typed PPLUS will return from
                         the current command level to the lowest
                         command level.  Default = WAIT.

            /[NO]OVERLAY Controls whether PPLUS overlays the
                         plot on the preceeding plot. The default
                         is /NOOVERLAY which causes the plot
                         to be a new plot.  The axes and their 
                         labels are not redrawn.  Moveable labels
                         (LABS command) will redraw.
     VELVCT,rlenfact,inc

               Does  a  vector  plot  of  u,v  pairs  located  at  x,y
          locations.   This  plot  is  done on a two dimensional field
          (compared to PLOTV and PLOTUV which  are  one  dimensional).
          To  use VELVCT the data must be stored as two lines.  Line 1
          containing  u,v  data  pairs,  and  line  2  containing  the
          corresponding x,y location pairs.  The lines are loaded with
          data in the ordinary manner.  Default length scaling is  set
          to the minimum inches/user_unit along the x and y axis.

            rlenfact = scaling factor for vector length  
                       (default = 1.0)
            >0 scale = rlenfact * inches/user_unit on x-axis
            <0 scale = rlenfact * inches/user_unit on y-axis

            inc = plots every inc vectors (subsamples)


          example:

          xaxis,0,4,1
          yaxis,1,8,1
          nlines,2



COMMAND DESCRIPTION                                         Page 12-27


          enter
          2.2,3.3
          5.0,6.0
          1.3,2.0
          3.0,0.0
          0.5,7.3
          1.3,4.4
          1.1,4.2
          end
          enter
          1,2
          3,3
          2,2
          3,5
          2,6
          2,7
          3,2
          end
          velvct,-.3,2

          reads 7 x,y and u,v pairs storing them as lines then plots
          every other vector
          scaled .3 * inches/user_unit on y-axis.


     VIEW/qualifiers,ZSCALE,IC,ZMIN,ZMAX,VCOMP,label

               Does a 3 dimensional surface plot.  Label is optional.

          ZSCALE = scale of the z data   default=(YMAX - YMIN)/
                   (ZMAX - ZMIN)
          IC = 0 set Xscal = Yscale, =1 no effect.   default=0
          ZMIN = set the base of the surface plot to ZMIN.  default:
                 use ZMIN from the data
          ZMAX = set the top of the surface plot to ZMAX.  default:
                 use ZMAX from the data
          VCOMP = Vector component to use for plotting (see the
                  VECTOR command).  Default is 1.

           Valid qualifiers are:

            /[NO]WAIT    Controls whether PPLUS pauses after plot 
                         completion.  Pause is signaled by a tone
                         and terminated by typing a character. If
                         an <ESC> is typed PPLUS will return from
                         the current command level to the lowest
                         command level.  Default = WAIT.

            /[NO]OVERLAY Controls whether PPLUS overlays the
                         plot on the preceeding plot. The default
                         is /NOOVERLAY which causes the plot
                         to be a new plot.  The axes and their 
                         labels are not redrawn.  Moveable labels



COMMAND DESCRIPTION                                         Page 12-28


                         (LABS command) will redraw.

               Best results are normally obtained by  using  defaults.
          Using scales does not change the data buffer.


     VPOINT,X,Y,Z

               Sets the viewpoint coordinates  for  surface  plotting.
          To  create  a  surface  plot  use  the  VIEW  command.   The
          viewpoint coordinates are available in  the  global  symbols
          PPL$VIEW_X,  PPL$VIEW_Y  and  PPL$VIEW_Z.  X, Y and Z form a
          right handed coordinate system with the Z axis up and Y axis
          into the page.
          X = x coordinate of viewpoint
          Y = y coordinate of viewpoint
          Z = z coordinate of viewpoint


     WHILE expression THEN

               The first  element  of  a  WHILE  statement  the  other
          element is ENDW.  ENDW is not valid in any other context.
          expression = argument operator argument
            argument = symbol name, number or a string enclosed by
          quotes
            operator = .EQ., .NE., .LT., .GT., .LE. or .GE.

               The symbol name can be undefined and its value is  then
          "" (i.e., null string).


     WINDOW,ON/OFF

               Windows the data to within the axes.  default=OFF


     XAXIS,XLO,XHI,XTIC

               Sets the x-axis characteristics.  If TYPEX  is  not  1,
          then  XLO and XHI must be the log of the minimum and maximum
          (must be integral values).  XAXIS without  arguments  resets
          the  auto  scaling.   Auto  scaling does consider LIMITS and
          does not consider WINDOW,ON.
          XLO = axis minimum (beginning of axis)
          XHI = axis maximum (end of axis)
          XTIC = dx distance between large tics


     XFOR,frmt



COMMAND DESCRIPTION                                         Page 12-29


               Sets the format for the x axis label.

          frmt = 0 or (a format)   default=0 (auto label)

               To create an integer  numeric  label  the  format  must
          begin  as "(I" or "(i".  A latitude or longitude axis can be
          created  by  specifying  ''LAT''),  ''LON''),  ''LONE'')  OR
          ''LONW'')  in  the  format.   Two single quotes are required
          because PPLUS symbol substitution will occur with  1  single
          quote.    The   hemisphere  designation  will  be  inserted.
          Longitude must be continuous across the dateline  with  west
          positive  for ''LON'' or ''LONW'', i.e., 135 is 135W and 190
          is 170E.  For ''LONE'' longitude is  continuous  across  the
          dateline  with  east  positive, i.e., 135 is 135E and 190 is
          170W.


     XLAB,label

               Enters the x-axis label.  Label is ignored if TAXIS  is
          on.


     YAXIS,YLO,YHI,YTIC

               Same as XAXIS.


     YFOR,frmt

               Same as XFOR.


     YLAB,label

               Enters the y-axis label.



                                                                 Page Index-1


                                       INDEX



       %, 10-1                             Get, 12-9
       @, 7-1, 11-1, 12-1, 12-3            Grid, 12-9
        
       Arrays, 7-6                         Help, 12-9
       Auto, 12-2                          Hlabs, 12-10, 12-14
       Autolab, 12-2                       Hlp, 12-10
       Axatic, 12-2
       Axlabp, 12-2                        If, 7-5, 12-10
       Axlen, 12-2, 12-21 to 12-22         Inc, 7-5, 12-10
       Axlint, 12-2
       Axlsze, 12-3                        Label, 5-4, 8-1 to 8-2, 9-2, 12-2
       Axnmtc, 12-3                            to 12-4, 12-6, 12-10 to 12-11,
       Axnsig, 12-3                            12-14, 12-16 to 12-17, 12-19,
       Axset, 12-3                             12-22, 12-27 to 12-29
       Axtype, 12-3                        Labels, 12-13
                                           Labs, 12-10 to 12-11, 12-14,
       Baud, 12-3                              12-19
       Bibo, 9-1                           Labset, 12-10 to 12-11, 12-13 to
       Box, 12-3                               12-14
                                           Lev, 12-11, 12-16
       C, 12-3                             Levels, 12-13
       Clsplt, 12-4                        Limits, 12-12 to 12-13
       Color, 8-3                          Line, 12-12
       Conpre, 12-4, 12-6                  Lines, 12-13
       Conpst, 12-4                        Linfit, 12-13
       Conset, 12-4, 12-13                 List, 12-13
       Continuation lines, 3-1             Listsym, 12-14
       Contour, 5-1, 5-4 to 5-5, 12-4,     Llabs, 12-10 to 12-11, 12-14
           12-13
       Cross, 12-5                         Markh, 12-6, 12-14
       Ctd, 10-4, 12-9                     Metric, 12-15
                                           Mom, 6-1
       Data, 12-13                         Multplt, 12-6, 12-15
       Datpt, 12-5, 12-13 to 12-14
       Debug, 12-6                         Nlines, 12-13, 12-15, 12-17
       Dec, 7-5, 12-6
       Delete, 12-6                        Origin, 12-15
       Dfltfnt, 12-6
       Dir, 12-6                           Pen, 8-3, 12-4 to 12-5, 12-11,
       Dsf, 9-2                                12-14, 12-16
                                           Plot, 5-1, 12-13, 12-16
       Echo, 12-6                          Plotuv, 12-17
       English, 12-7                       Plotv, 12-16
       Enter, 12-7                         Pltnme, 6-1, 12-17
       Epic, 9-2, 12-2, 12-7, 12-18        Pltype, 12-17
       Evar, 12-7, 12-18                   Ppl$command_file, 12-1
                                           Ppl$format, 12-9
                                           Ppl$height, 12-21
       Fonts, 8-2                          Ppl$input_file, 12-18, 12-20 to
       Format, 5-1, 9-1, 12-9, 12-18           12-21
       Functions, 7-7                      Ppl$lf_a, 12-13



                                                                 Page Index-2


       Ppl$lf_a_stdev, 12-13               Subscripts, 8-3
       Ppl$lf_b, 12-13                     Superscripts, 8-3
       Ppl$lf_b_stdev, 12-13               Symbol, 7-6
       Ppl$lf_r2, 12-13                    Symbol arrays, 7-6
       Ppl$lf_res_var, 12-13
       Ppl$lf_var, 12-13                   Taxis, 5-6, 12-13, 12-16, 12-22,
       Ppl$pltnme, 12-17                       12-29
       Ppl$teknme, 12-22                   Teknme, 12-22
       Ppl$view_x, 12-28                   Tics, 12-2 to 12-3, 12-13, 12-22,
       Ppl$view_y, 12-28                       12-28
       Ppl$view_z, 12-28                   Time, 12-22
       Ppl$width, 12-21                    Title, 12-23
       Ppl$xfact(n), 12-23                 Tktype, 12-23
       Ppl$xlen, 12-2                      Transxy, 12-13, 12-23
       Ppl$xoff(n), 12-23                  Txlabp, 12-24
       Ppl$xorg, 12-16                     Txlint, 12-24
       Ppl$yfact(n), 12-23                 Txlsze, 12-24
       Ppl$ylen, 12-2                      Txnmtc, 12-24
       Ppl$yoff(n), 12-23                  Txtype, 12-24
       Ppl$yorg, 12-16
                                           Vars, 5-1, 9-1, 12-18, 12-24
       Rd, 5-1, 5-3, 9-1, 12-13, 12-18,    Veckey, 12-25
           12-20                           Vecset, 12-25
       Read, 12-13                         Vector, 12-5, 12-13, 12-19, 12-26
       Reset, 12-19                            to 12-27
       Return, 12-19                       View, 12-27
       Rlabs, 12-10 to 12-11, 12-14,       Vpoint, 12-28
           12-19
       Rotate, 6-1, 12-19                  While, 7-5, 12-28
       Rwd, 12-20                          Window, 12-28
        
       Save, 12-9, 12-20                   Xaxis, 12-13, 12-28
       Set, 12-20                          Xfor, 12-28
       Show, 12-21                         Xlab, 12-29
       Size, 12-21
       Skp, 5-1, 5-3, 12-20 to 12-21
       Smooth, 12-21                       Yaxis, 12-13, 12-29
       Spawn, 12-21                        Yfor, 12-29
       Stats, 12-13                        Ylab, 12-29

