NAME

     grot  - apply global rotation to 2-component seismic data

SYNOPSIS

     grot [ -Nntap ] [ -Ootap ] [ -Fftap ] [ -aang ] [ -nsnstr  ]
     [ -nenetr ] [ -rsnrst ] [ -renred ] [ -V ] [ -? ]

DESCRIPTION

     grot reads 2-component  seismic  data  and  sample-by-sample
     applies a rotational transformation based on the angle.  The
     input data is an interleaved 2-compnent stream such  as  the
     output  of  running  mergn on two data sets with the -m flag
     set (multiplex on).  The transformation is given by

          out1(i) =  cos(ang) * in1(i) + sin(ang) * in2(i)

          out1(i) = -sin(ang) * in1(i) + cos(ang) * in2(i)

     where in1 and in2 are two side-by-side  traces  representing
     two components.

     grot gets both its data and its parameters from command line
     arguments.   These  arguments specify the input, output, the
     start and end traces, start and  end  records,  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).

     -F ftap
          Enter the data set name of the input (rec,angle)  flat-
          file  immediately after typing -F.  If not present this
          file is not used and the rotation angle is  taken  from
          the -a entry (see below).

     -a ang
          Enter the rotation angle in degrees (default = 0).

     -ns nstr
          Enter the start trace number (should refer to the first
          component).   The  default  is  the  first trace of the
          record.

     -ne netr
          Enter the end trace number (should refer to the  second
          component). The default is the last trace of the record
          minus 1.

     -rs nrst
          Enter start record number.  Default value is the  first
          record.

     -re nred
          Enter end record number.  Default value is last record.

     -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

     unknown

SEE ALSO

     mergn, umerg

AUTHOR

     Paul Gutowski, TRC, x3146

COPYRIGHT

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