NAME

     navcheck - Navigation check of 3D seismic data and flag  bad
     traces as dead.

SYNOPSIS

     navcheck [ -Nntap ] [  -Ootap  ]  [  -X1xgraph_bad_nav  ]  [
     -X2xgraph_bad_offsets  ] [ -X2xgraph_bad_range ] [ -nsnstr ]
     [ -nenetr ] [ -rsnrst ] [ -renred ] [ -valuevalue ] [  -tol-
     tolerance  ]  [  -mindistmin_dist  ]  [ -maxdistmax_dist ] [
     -dxgroup_interval ]  [  -hw1HdrWrd1  ]  [  -hw2HdrWrd2  ]  [
     -hw3HdrWrd3   ]  [  -hw4HdrWrd4  ]  [  -xminurvey_Xmin  ]  [
     -yminurvey_ymin ] [ -xmaxurvey_Xmax ] [ -ymaxurvey_ymax ]  [
     -W ] [ -D ] [ -L ] [ -R ] [ -V ] [ -? ]

DESCRIPTION

     navcheck Checks the navigation information of a  3D  seismic
     survey  and  flags  bad traces as dead by putting 30000 into
     the StaCor..  This is done in the following ways:  1)  check
     the  header  words  with  source  and  recieve  values for a
     specific user defined value.  2) check  the  values  in  the
     source  and  reciever  header words against the user defined
     survey limits assuming a quadralateral.  3) check  the  dis-
     tance  values  in  DstSgn against values calculated from the
     source and reciever locaations in hw1-4.  4)  check  maximum
     possible  range of distance in DstSgn against a user defined
     value.  Other methods can always be added, call  Gridley  at
     socon 422 - 3842.

     Navcheck produces  3 xgraph files ready for graphing.  These
     files  define the location of any source/reciever which fail
     any of the navigation checks above and sorts these into dif-
     ferent  file  for  QC.   This can be useful for defining any
     systematic problems in the survey when plotted.

     Navcheck gets both its data and its parameters from  command
     line  arguments.  These arguments specify the input, output,
     the start and end traces, the start  and  end  records,  and
     verbose

  Command line arguments
     -N ntap
          Enter the input data set name or file immediately after
          typing  -N  (can  be  piped).   This  input file should
          include the complete path name if the file resides in a
          different  directory.   Example  -N/vsp/dummy tells the
          program to look for file 'dummy' in directory 'vsp'.

     -O otap
          Enter the output data  set  name  or  file  immediately
          after typing -O (see above).


     -X1 xgraph_file_bad_nav
          Enter the output data set name for xgraph file with bad
          navigation x and y positions. (Optional)

     -X2 xgraph_file_bad_distance
          Enter the output data set name for xgraph file with bad
          distance x and y positions. (Optional)

     -X3 xgraph_file_bad_range
          Enter the output data set name for xgraph file with bad
          range x and y positions. (Optional)

     -ns nstr
          Enter the processing start trace number.  Trace numbers
          below  this  value  will  not  be processed but will be
          passed.  The default is 1.

     -ne netr
          Enter the processing end trace number.   Trace  numbers
          above  this  value  will  not  be processed but will be
          passed.  The default is the last trace  number  on  the
          input data set.

     -rs nrst
          Enter processing start record number.   Record  numbers
          below  this  value  will  not  be processed but will be
          passed. Default value is the first record.

     -re nred
          Enter processing end  record  number.   Record  numbers
          above  this  value  will  not  be processed but will be
          passed. Default value is last record.

     -value value
          Enter the key value to search the header words  (hw1-4)
          for.  Default = 0.

     -tol tolerance
          Enter the tolerance for distance exclusion .  Default =
          25.

     -mindist mindist
          Enter the minimum distance for spread.  Default = 0.

     -maxdist maxdist
          Enter the maximum distance for spread.  Default = 5000.

     -dx group interval
          Enter the group interval of spread.  Default = 25.

     -hw1 headerword1
          Enter the header word for Source Point  X.   Default  =
          SrPtXC

     -hw2 headerword2
          Enter the header word for Source Point  Y.   Default  =
          SrPtYC

     -hw3 headerword3
          Enter the header word for Reciever Point X.  Default  =
          RcPtXC

     -hw4 headerword4
          Enter the header word for Reciever Point Y.  Default  =
          RcPtYC

     -xmin xmin
          Enter the minimum x limit of survey.  Default = 0.

     -ymin ymin
          Enter the minimum y limit of survey.  Default = 0.

     -xmax xmax
          Enter the maximum x limit of survey.  Default = 0.

     -ymax ymax
          Enter the maximum y limit of survey.  Default = 0.

     -W   Use the Header Word limit check (-value).

     -D   Use the distance calculation check  (-mindist/-maxdist,
          -tol).

     -L   Use the survey limit check on x and y  values  (-xmin,-
          xmax,-ymin,-ymax).

     -R   Use   the   maximum   range   limit   on   DstSgn    (-
          mindist,maxdist).

     -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.

BUGS

     unknown

AUTHOR

     James Gridley


     Proprietary - for the  exclusive  use  of  Amoco  Production
     Company and other wholly owned subsidiaries of Amoco Produc-
     tion

COPYRIGHT

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