NAME

     miror - module to pad records  of  data  by  mirroring  real
     traces at the front and back of the records.

SYNOPSIS

     miror [ -Nntap ] [ -Ootap ] [ -rs ] [ -re ] [ -md ] [ -n   ]
     [ -d  ] [ -R  ] [ -? ] [ -H ]

DESCRIPTION

     miror pads records of seismic data to minimize edge  effects
     from  the  application  of  spatial  filters  by mirroring a
     user-specified number of traces from the front  and/or  back
     of  the records, where front means at trace 1 and back means
     at the last trace in the  record.   The  first  and  last  N
     traces  are  repeated  at  the  front and back of the record
     using the first and last trace as a pivot point.  This means
     that if the user requests five traces to be used in the mir-
     ror, the trace sequence in each output record,  relative  to
     the input, will be trace 5, trace 4, trace 3, trace 2, trace
     1, trace 2, trace 3, etc.  The option is given  to  extrapo-
     late  trace  distances  from the input trace distances.  The
     program  will  automatically  determine  the  direction   of
     increase  or  decrease of offset and increment and/or decre-
     ment appropriately.  The previous miror can  be  removed  by
     specifying -R on the command line.

     Miror gets its data and parameters from command  line  argu-
     ments.   These  arguments  specify the input and output data
     set names, the number of traces  to  be  mirrored,  and  the
     method of handling offsets.

  Command line arguments
     -N ntap
          Enter the input data set name immediately after  typing
          -N.   This  input file should include the complete path
          name if the file  resides  in  a  different  directory.
          Example  -n/b/tsp/dummy  tells  the program to look for
          file 'dummy' in directory '/b/tsp'.  (Default = stdin)

     -O otap
          Enter the output data set name immediately after typing
          -O.   Specify  the  full  path  to  write the file to a
          directory other than  the  current  working  directory.
          (Default = stdout )

     -rs start record
          Enter the sequential number of the record on  which  to
          begin  processing.   All data prior to this record will
          be skipped and not output.  (Default = first)

     -re record end
          Enter the sequential number of the record on  which  to
          end processing.  All data following this record will be
          skipped and not output.  (Default = last)

     -md operations mode
          Enter the flag indicating whether mirroring is to occur
          at the front and back of a record or at the front only.
          A value of 0 specifies front and back.  A  value  of  1
          specified front only.  (Default = 0)

     -n number of traces in the mirror
          Enter the number of traces to mirror  about  the  first
          and  last  trace  in  the  record.   (Default = 1/2 the
          number of traces per input record)

     -d offset handling
          Enter the value indicating the method of  handling  the
          distance  values  in  the  trace  header.  A value of 0
          specifies that the distances are to  remain  unchanged.
          A  value  of  1 requests extrapolation of offsets using
          the first and last values  and  the  increment  at  the
          front and back of the record. (Default = 0)

     -R remove previous miror
          Remove the previously mirrored  traces.   Program  will
          scan the historical line header of the input data, find
          the last miror run and use the md and n parameters that
          were specified or the appropriate defaults.  When -R is
          specified, -md or -n values on the command line will be
          ignored.

     -?  Enter the command line argument '-?' to get online help.
     The program terminates after the help screen is printed.

     -H Enter the command line argument -H to  get  online  help.
     The program terminates after the help screen is printed.

SEE ALSO

        embed(1)

AUTHOR

        Richard Crider E&PT  Houston

COPYRIGHT

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