NAME

     tvdin  - module to associate [t,v,d] function output by  the
     USP  routine  tvd  with  the  endpoint  seismic data for nmo
     correction with the dip term using the USP routine tvdnmo.

SYNOPSIS

     tvdin [ -Nntap ] [ -Ootap ] [ -vvtap ] [ -R ] [  -shot  ]  [
     -receiver ] [ -cdp ] [ -pri ] [ -hwiwd ] [ -V ] [ -? ]

DESCRIPTION

     tvdin allows the user to create a record by record  velocity
     &  dip  traces  from  a  model file for use with the program
     tvdnmo. The input is from the standard input unless the flag
     -N is specified, and the velocity model file is given on the
     standard output, unless the -O flag is specified.  Output is
     in  the form of two trace records (one for each input record
     to be processed):  the first being the velocity at each sam-
     ple; the second being the dip in radians at each sample.

     The velocity file is in USP format  and  must  be  generated
     using  the  data stream to be tvdnmo'd as the input file, to
     guarantee that the header information is consistent. This is
     because the program tvdnmo reads both the trace file and the
     velocity file in exactly the same sequence.

  Command line arguments
     -N ntap
          Enter the full path of the  file  continuing  the  data
          set.  Usually  the  best  procedure is to type out your
          sisort command line and pipe that into tvdin.  If  ntap
          is  not specified a pipe input is expected on the stan-
          dard input. If standard input  is  not  specified,  and
          there  is no input to the program, e.g., program run in
          background, expect a very ungracious  crash.   (default
          standard input)

     -O otap
          Output   file   name   for    desired    records    and
          traces.(default is standard output)

     -v vtap
          Time-velocity-dip file:  this file output from the  USP
          routine  tvd  which  takes  the time-distance model and
          calculates  the  dip-velocity  required  to  tweak  the
          modelled events into their respective quadrants.

     -R   If present regular  data  numbering  is  assumed.   The
          appropriate  header  value is read from the first trace
          of the input data and the subsequent values are  deter-
          mined by incrementing this value by 1 each time.


     -shot
          use shot location as reference [SrcLoc]

     -receiver
          use group location as reference [RecInd]

     -cdp use cdp location as reference [DphInd]

     -pri use permanent record location as reference [PrRcNm]

     -hw iwd
          give the actual trace header mnemonic to  use  for  the
          record  numbering  of the velocity file.  Of course use
          of this entry will obviate all above flags.

     -V   Very verbose mode.

      -? -h -help
          tvdin will send a description of the command line argu-
          ments and stop.

BUGS

     The individual trace number can be changed,  check  original
     header information by scan program.

SEE ALSO

     tvd, tvdnmo, velin

AUTHOR

      re-write by P.G.A. Garossino [ATTC:X3932]
      [original USP code by P.Gutowski, 1989]

COPYRIGHT

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