NAME

     adjsum - do adjacent trace stack

SYNOPSIS

     adjsum [ -Nntap ] [ -Ootap ] [ -gsgs ] [ -V ] [ -? ]

DESCRIPTION

     adjsum reads input data and stacks every n traces, averaging
     a  number  of  the trace header words as well as normalizing
     the output traces by the number of live samples in the  sum-
     mation  at  every  sample  point.  The header words averaged
     are: SrPtXC, SrPTYC, RcPtXC, RcPtYC, SrRcMX, SrRcMY, CDPBCX,
     CDPBCY,  DstSgn, StaCor. Dead traces (StaCor = 30000) do not
     participate in the summation.  It  is  strongly  recommended
     that  some  form  of brute promary NMO correction be applied
     prior to input into this code (and of course  that  the  NMO
     correction be reversed on the output data).

     For 3D data  you  often  have  several  lines  or  streamers
     included  in a single record. It is recommended that utop be
     run prior to adjsum change the line header so that each line
     or  streamer  is  a record (with the number of records being
     increased accordingly). A follow  on  utop  will  reset  the
     number  of  records  and  number of trace per record back to
     their original values.

     adjsum gets both its data and its  parameters  from  command
     line  arguments.  These arguments specify the input, output,
     and the number of traces in the adjacent trace stack.

  Command line arguments
     -Nntap
          Enter the input data set name or file immediately after
          typing  -N;  entering  nothing  specifies a stdin pipe.
          This input put 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.

     -Ootap
          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).

     -gs gs
          (integer) Enter the number of traces  in  the  adjacent
          trace  stack.  This  must be exactly divisible into the
          input number of traces per record. Default = 2

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

     -?   Enter this (or '-?' if you are running in  c-shell)  to
          get  online  help.   The  program  will terminate after
          printing this.

EXAMPLE

     bdnmo -N indata -v brute_vel | \
     utop -L 240 -R 500 | \
     adjsum -gs 2 | \
     utop -L 960 -R 125 | \
     bdnmo -O odata -v brute_vel -R

     where a single brute NMO correction has been applied to  the
     input  data  before adjacent 2 trace summation and unapplied
     after the summation. The input data is composed of 125 shots
     each  with  4  streamers  of 240 channels. A utop is used to
     reset the line header before adjacent trace stacking to sin-
     gle  streamer  records.  A  follow on utop resets these line
     header values.

BUGS

     Unknown

AUTHOR

     Paul Gutowski, TRC x3146, pgutowski@amoco.com

COPYRIGHT

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