NAME

     flatt2d - convert flat file from time to depth using a velo-
     city field.

SYNOPSIS

     flatt2d [ -P1inpick ] [  -P2outpick  ]  [  -V1velfield  ]  [
     -Ddefvalue ] [ -iliili ] [ -idiidi ] [ -dzdz ] [ -V ] [ -? ]
     [ -h ]

DESCRIPTION

     flatt2d reads an ascii file with "li di ms" triplets  and  a
     usp  velocity  cube.  The ascii file should contain one tri-
     plet per line.  Each member of each  triplet  in  the  ascii
     file  must  be  separated by white space.  The velocity grid
     should contain records which correspond to line indices  and
     traces  which  correspond  to depth indices (lines and cmps,
     respectively).  The input horizon picks can be either  grid-
     ded  or  not  gridded.  The output horizon picks will not be
     output in the same order as input.

     flatt2d gets both its dataset names and its parameters  from
     command  line  arguments.  These arguments specify the input
     horizon file, the output horizon file, the  velocity  field,
     the li and di biases.

  Command line arguments
     -P1inpick
          Enter the input ascii  horizon  file  name  immediately
          after  typing  -P1.  This input file should include the
          complete path name if the file resides in  a  different
          directory.  Example -L/b/vsp/dummy tells the program to
          look for file 'dummy' in directory 'vsp' stored on  the
          'b' disk.

     -P2outpick
          Enter the output ascii horizon file name  after  typing
          -P2.   The output file also requires the full path name
          (see above).

     -V1velfield
          Enter the name of the  usp-compatible  velocity  field.
          Input the file name immediately after typing -V1.  Pro-
          gram flatt2d assumes the records and traces start their
          numbering at 1.

     -Ddefvalue
          Enter the default time value to be converted to  depth.
          If  a value is input, then their will be an output pick
          for every li and di on the velocity field.   The  input
          time will be correctly converted to depth.


     -iliili
          Enter the starting li that  corresponds  to  the  first
          record  on the velocity field.  This value will be sub-
          tracted from the li in the ascii file (assumed to be in
          the first field) to map into the velocity records.  The
          default is 1 which will work correctly if the first  li
          is  1.   This  bias  will be restored on output.  N ote
          that an input pick will not be output if it is  not  in
          the domain of the velocity field.

     -idiidi
          Enter the starting di that  corresponds  to  the  first
          trace  on the velocity field .  This value will be sub-
          tracted from the li in the ascii file (assumed to be in
          the second field) to map into the velocity traces.  The
          default is 1 which will work correctly if the first  di
          is 1.  This bias will be restored on output.  Note that
          an input pick will not be output if it is  not  in  the
          domain of the velocity field.

     -dz  Enter the depth interval between consecutive samples on
          the input velocity field after typing '-dz' on the com-
          mand line.  This value will override  the  line  header
          value Dx1000 in the input velocity field.

     -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.

     -h   Enter this option to get online help.  The program will
          terminate after printing this.

SEE ALSO

     flatd2t gxd2t gxt2d, xsdt2d, xsdd2t, and vttd.

BUGS

     The output picks will not be in the same order as the  input
     picks.   The  first  pick  in  may be the last pick out, for
     example.  The output picks will be sorted first  by  li  and
     secondarily by di.

AUTHOR

     Gary Murphy

COPYRIGHT

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