vpad

     vpad - pad/remove samples from first 3 axes of a dataset

SYNTAX

     vpad [ -N filename -O filename
            -1b begpad1 -1e endpad1
            -2b begpad2 -2e endpad2
            -3b begpad3 -3e endpad3
            -val padval -dead -h ]

DESCRIPTION

     vpad adds or removes samples from the axes of a 3D  velocity
     field.  Samples  are added with positive values for the pad-
     ding variables, samples are removed  with  negative  values.
     The  padding  default is to replicate values into the padded
     region. This can be changed to fill padded  regions  with  a
     constant value.

OPTIONS

     -N filename
          Enter the input dataset name or file immediately  after
          typing  -N.  This file should include the relative path
          name if the file resides in a different directory.  The
          default is to read data from stdin:

     -O filename
          Enter the output dataset name or file immediately after
          typing  -O.  This file should include the relative path
          name if the file resides in a different directory.  The
          default is to write data on stdout:

     -1b begpad1, -1e endpad1
          Enter the number of samples to pad at the beginning and
          at  the  end  of axis 1 (# of samples to pad at the top
          and  bottom  of  each  trace).   (default:   begpad1=0,
          endpad1=0)

     -2b begpad2, -2e endpad2
          Enter the number of samples to pad at the beginning and
          at  the end of axis 2 (# of traces to pad at the begin-
          ning and end  of  each  record).  (default:  begpad2=0,
          endpad2=0)

     -3b begpad3, -3e endpad3
          Enter the number of samples to pad at the beginning and
          at the end of axis 3 (# of records to pad at the begin-
          ning and end  of  the  dataset).  (default:  begpad3=0,
          endpad3=0)

     -val padval
          This parameter will force padded samples to  be  filled
          with  padval. (default: replicate samples)

     -dead
          Use -dead to flag padded traces as  dead.  This  stuffs
          30000 in the StaCor trace header field.

     -h or -?
          Print online help to the terminal.

EXAMPLE

         vpad -N velocity_in.usp  -1b 45 -val1500 |\
         vpad -O velocity_out.usp -2b -8 -2e 12

     This will pad 45 samples with the value 1500 to the  top  of
     each  trace  and  then remove 8 traces from the beginning of
     each record, while copying the last trace 12  times  at  the
     end of each record.

BUGS

     None known

AUTHORS

     M.J. O'Brien