NAME

     cross2d - 2D crosscorrelation of seismic records


SYNOPSIS

     cross2d [ -N1ntap1 ] [ -N2ntap2 ] [ -Ootap ] [ -lagxlagx ] [
     -lagylagy  ] [ -ss1ss1 ] [ -es1es1 ] [ -ns1ns1 ] [ -ne1ne1 ]
     [ -rs1irs1 ] [ -re1ire1 ] [ -ss2ss2 ] [ -es2es2 ] [  -ns2ns2
     ] [ -ne2ne2 ] [ -rs2irs2 ] [ -re2ire2 ] [ -ttaper ] [ -V ] [
     -? ]


DESCRIPTION

     cross2d computes the two  dimensional  crosscorrelation  for
     two  input  data sets. Specifically designed to work on time
     slice data but  can  be  used  on  any  multi-trace  seismic
     record.  An  ideal  application  would  be  correlating time
     slices of two data sets. The correlation is done as  a  com-
     plex  multiplication  in the KxKy domain in the interests of
     speed. A cosine  taper  may  be  applied  to  minimize  edge
     effects.

     Data set 2 must be at least as large as data set  1  (as  in
     the  one  dimensional program cross).  Data set 1 can either
     be a single record or multi-record as long as the number  of
     records is exactly equal to data set 2.

     The zero lag position will be located in the exact center of
     each  output  record  (for  input records that have the same
     dimensions). The default dimension of the output will be the
     maximum  of  each  of  the  dimensions of the input with one
     added to make the output dimensions odd. This  ensures  that
     the  zero  lag sample is exactly in the center of the output
     record.

     cross2d gets both its data and its parameters  from  command
     line  arguments.  These arguments specify the input, output,
     the start and end traces, start and end samples,  start  and
     end records, and verbose printout, if desired.et 2, and that
     if data set 1 has multiple records it  must  have  the  same
     number of records as data set 2.

  Command line arguments
     -N1 ntap1
          Enter the input data set 1  name  or  file  immediately
          after  typing  -N1.   The  N1  data  set  should be the
          wavelet or pilot record; the N2 data set should be  the
          primary  data  set.  This input file should include the
          complete path name if the file resides in  a  different
          directory.   Example -N1/vsp/dummy tells the program to
          look for file 'dummy' in directory 'vsp'.  Data  set  1
          can not be piped (except in XIKP.

     -N2 ntap2
          Enter the input data set 2  name  or  file  immediately
          after  typing  -N2.   The  N1  data  set  should be the
          wavelet or pilot signal; the N2 data set should be  the
          primary data set. Data set 2 can be piped (stdin).

     -O otap
          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).

     -lagx lagx
          Enter the total (positive and negative) lags in  the  x
          or  trace  direction. The default is to use the maximum
          of this dimension of N1 and N2. This value  is  checked
          to  make sure it is odd to ensure the zero lag position
          is the exact center of the output record (assuming that
          the input records have equal dimensions).

     -lagy lagy
          Enter the total (positive and negative) lags in  the  y
          or  sample direction. The default is to use the maximum
          of this dimension of N1 and N2. This value  is  checked
          to  make sure it is odd to ensure the zero lag position
          is the exact center of the output record (assuming that
          the input records have equal dimensions).

     -ss1 ss1
          Enter the start sample of data set 1.  The  default  is
          the beginning of each trace.

     -es1 es1
          Enter the end sample of data set 1.  The default is the
          end of each trace.

     -ns1 ns1
          Enter the start trace of each record  of  data  set  1.
          The default is the beginning of each record.

     -ne1 ne1
          Enter the end trace of each record of data set 1.   The
          default is the end of each record.

     -rs1 irs1
          Enter the start record of data set 1.  The  default  is
          the  beginning  of  the  data  set. If the number of N1
          records is not equal  to  1  the  total  number  of  N1
          records  chosen  (or defaulted) must be the same as for
          N2.

     -re1 ire1
          Enter the end record of data set 1.  The default is the
          end of the data set. If the number of N1 records is not
          equal to 1 the total number of N1  records  chosen  (or
          defaulted) must be the same as for N2.

     -ss2 ss2
          Enter the start sample of data set 2.  The  default  is
          the beginning of each trace.

     -es2 es2
          Enter the end sample of data set 2.  The default is the
          end of each trace.

     -ns2 ns2
          Enter the start trace of each record  of  data  set  2.
          The default is the beginning of each record.

     -ne2 ne2
          Enter the end trace of each record of data set 2.   The
          default is the end of each record.

     -rs2 irs2
          Enter the start record of data set 2.  The  default  is
          the beginning of the data set. Note that if the N1 data
          set contains (or is selected such that  it  has)  other
          than  a single record then -rs2[] -re2[] must be chosen
          so that the number of records is the same as for N1.

     -re2 ire2
          Enter the end record of data set 2.  The default is the
          end  of the data set. Note that if the N1 data set con-
          tains (or is selected such that it has)  other  than  a
          single record then -rs2[] -re2[] must be chosen so that
          the number of records is the same as for N1.

     -t taper
          Enter the percent taper to apply. The taper is a cosine
          function  and  is  specified as a percent of the dimen-
          sions of the input records. This percent zone  will  be
          tapered on both sides of each direction.  Default = 10

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

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


AUTHOR

     Paul Gutowski, pgutowski@amoco.com


COPYRIGHT

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



















































Man(1) output converted with man2html