NAME

     wrot  - module to rotate 3 component data about a given com-
     ponents axis.

SYNOPSIS

     wrot [ -Nntap ] [ -Ootap ] [ -Pptap ] [ -rsnrst ] [  -renred
     ]  [ -xxcomp ] [ -yycomp ] [ -zzcomp ] [ -dtdeltat ] [ -flat
     ] [ -pick ] [ -rotangle ] [ -ROTangle ] [ -V ] [ -? ]

DESCRIPTION

     wrot computes, for each input  record,  the  polar  rotation
     angle corresponding to the maximum amplitude vector found in
     the x,y plane within a user specified time window.  All  x,y
     data  within  the record is then rotated to that angle about
     the z axis.   Input data is expected  in  N  trace  records,
     where  N  is an integer multiple of 3.  [note: more than one
     source could result in more than three  traces  per  record,
     where each record corresponds to a particular receiver depth
     in the borehole.]  The first three  traces  [ie.  the  first
     source  recorded]  are  used  to compute the rotation angle.
     Designation of the x,y and z component trace is left to  the
     user.   The  maximum  amplitude  search  window  is input by
     either a flat file of StartTime, EndTime, Record values,  or
     a  pickfile containing one pick for window start and one for
     window end.

     wrot gets both its data and its parameters from command line
     arguments.   These  arguments  specify  the input and output
     datasets, the input search window pick/flat file, the  start
     and  end  traces,  the  trace corresponding to the x,y and z
     components,  the  pickfile  sample  units   over-ride,   the
     flatfile/pickfile flag and verbose printout, if desired.

  Command line arguments
     -N ntap
          Enter the input data set name or file immediately after
          typing -N unless the input is from a pipe in which case
          the -N entry must be omitted.  This input  file  should
          include the complete path name if the file resides in a
          different directory.  Example -N/b/vsp/dummy tells  the
          program to look for file 'dummy' in directory '/b/vsp'.

     -O otap
          Enter the output data  set  name  or  file  immediately
          after typing -O.  This output file is not required when
          piping the output to another process.  The output  data
          set also requires the full path name (see above).

     -P ptap
          Enter the name of the  pick/flat  file  containing  the
          maximum  amplitude search window parameters immediately
          after typing -P.  This input file  should  include  the
          complete  path  name if the file resides in a different
          directory.  Example -N/b/vsp/dummy tells the program to
          look for file 'dummy' in directory '/b/vsp'.

          This file may either be a pick file in XSD format or  a
          flat file in the following format:

           StartTime,EndTime,Record
           StartTime,EndTime,Record
           StartTime,EndTime,Record
               .        .      .
               .        .      .
               .        .      .
               .        .      .
           StartTime,EndTime,Record
           0        ,0      ,-1

          If using the XSD pickfile format wrot expects two  seg-
          ments  with  increasing  sequential record number.  The
          easiest way to satisfy this constraint is to  plot  one
          desired  trace  from  every record then pick the window
          start and end from left to right.  Should you forget to
          flag the pickfile with the correct sample units you may
          use the sample unit override (see below) to compensate.

     -rs nrst  [Default:first record]
          Enter start record number.

     -re nred  [Default:last record]
          Enter end record number.

     -x xcomp  [Default:1]
          Enter the number of the trace  containing  the  x  com-
          ponent data.

     -y ycomp  [Default:2]
          Enter the number of the trace  containing  the  y  com-
          ponent data.

     -z zcomp  [Default:3]
          Enter the number of the trace  containing  the  z  com-
          ponent data.

     -dt deltat  [Default:not used]
          Enter the pickfile sample units override in ms.

     -flat
          Enter the command line argument  '-flat'  when  a  flat
          file is used to input maximum amplitude search window.

     -pick
          Enter the command line argument  '-pick'  when  a  pick
          file is used to input maximum amplitude search window.

     -rot [Default:0]
          Enter  the  additional  rotation  angle  (in   degrees)
          desired.

     -ROT [Default:0]
          Enter the constant rotation angle (in degrees) desired.
          A NON-ZERO ENTRY RESULTS IN ONLY THIS ROTATION.

     -V   Enter the command line argument '-V' to get  additional
          printout.

     -?   Enter the command line  argument  '-?'  to  get  online
          help.   The program terminates after the help screen is
          printed.

BUGS

     Picks must be in increasing sequential  record  number.   If
     this proves too onerous give me a call and I will change the
     code to allow sorting of the input pick file.

SEE ALSO

     grot(1)

AUTHOR

     Original code by R.M. Alford, USP version  P.G.A.  Garossino
     [APR:3932,zpgg07@trc.amoco.com]

COPYRIGHT

     copyright 2001, Amoco Production Company
               All Rights Reserved
          an affiliate of BP America Inc.