NAME

     rwindow  - generate running analysis windows  of  a  stacked
     data set.

SYNOPSIS

     rwindow [ -Nntap ] [ -Ootap ] [ -ntrntr ] [  -npadnpad  ]  [
     -nlinenline ] [ -R ] [ -V ] [ -? ]

DESCRIPTION

     rwindow takes a seismic  stack  data  and  generates  output
     seismic  records  containing  overlapping running windows of
     seismic traces. The user is then able to apply  conventional
     record  based  2d  filtering,  such  as  fk or tau-p (linear
     radon) transforms  acheiving  a  space  varying  effect.  By
     invoking  the  -R  option,  the  overlapping  windows can be
     blended,  and  the  data  restored  to  its  original   data
     trace/record structure.

     rwindow gets parameters from command line arguments.   These
     arguments specify the input, output, the trace analysis win-
     dow, the number of  traces  to  be  padded,  and  the  trace
     separation in m (ft).

  Command line arguments
     -N ntap
          Enter the input data set name or file immediately after
          typing -N.  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 'vsp' stored on the 'b' disk.

     -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).

     -ntr ntr
          Enter the number of traces to be included in the output
          analysis  records  (windows)  if there were no overlap.
          (Default=200).

     -npad npad
          Enter the number of traces  to  be  used  to  pad  each
          analysis  record.  The  pad  should  be large enough to
          minimize any subsequent filter edge effects (eg from fk
          filtering) upon restoration. npad will be changed to be
          an odd number and stored in line header location RATFld
          for  use when invoking -R option. (Default =21 for for-
          ward  windowing,  drawn  from  trace  header  with   -R
          option).

     -dx dx
          Enter the trace distance. The  signed  trace  distances
          will  be filled in with a distance of zero being at the
          center trace in the output record. (No default for for-
          ward  mode  of  operation, unnecessary for restore (-R)
          mode).

     -nline nline
          Enter the number of seismic lines for 3D stacked  data.
          The data are assumed to be ordered in the inline direc-
          tion, such that nline is the number of seismic records.
          (Default  for  single  trace  record  input  data  = 1.
          Default for multi trace record input data =  number  of
          input records).

     -R   Enter this option if the data are  to  be  restored  to
          their original, unpadded mode.

     -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.

NOTE 1:

     The   flows    rwindow|radonf|polymute|radonr|rwindow    -R,
     rwindow|radonf|taupred|radonr|rwindow         -R         and
     rwindow|fft2da|polymute|fft2da -R|rwindow -R   can be  quite
     effective  in eliminating coherent noise on stacked sections
     in a space variable mode.

NOTE 2:

     The flow  rwindow|radonf -semb  |radonr|rwindow  -R  can  be
     used to increase coherency on stacked data.

NOTE 3 (LINE HEADERS):

     The old usp line header format has been extended in order to
     avoid  conflicts  when  running other algorithms on windowed
     data. When generating running windows in the  inline  direc-
     tion (default mode in rwindow):

     Header keyword           variable

     Nx_Pad                   npad NxLine                   nline
     (number   of   lines   in   the   inline  direction)  Nx_Rec
     nrec_inline  (number  of  inline  windowed  records)  Nx_Trc
     ntrpline  (number  of  inline traces of original unwindowe d
     line) Nx_Win                   number of traces in a  window
     (ntr+2*npad)

     When generating running windows in the  crossline  direction
     (invoked by using the -Y option in rwindow):

     Header keyword           variable

     Ny_Pad                   npad NyLine                   nline
     (number   of   lines  in  the  crossline  direction)  Ny_Rec
     nrec_inline (number of crossline  windowed  records)  Ny_Trc
     ntrpline (number of crossline traces of original unwind owed
     line) Ny_Win                   number of traces in a  window
     (ntr+2*npad)


     Trace header words:

     Header keyword           variable

     LRcCDP                   itrace_sort (running counter  along
     the line that will permit a sort in perpendicular direction)

BUGS

     No bugs known at present.

SEE ALSO

     editt,radonf,radonr,slstkf,slstkr,fft2da,polymute,taupred

AUTHOR

     Kurt J. Marfurt (1993).

COPYRIGHT

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