NAME

     XINIT - Initialization of Cross-Over Data Bases.


SYNOPSIS

     xinit -I


DESCRIPTION

     The purpose of xinit is to create two key files that will be
     holding  all  the cross-over information for all the cruises
     tested. These files are called xx_base.b and xx_legs.b,  and
     they  will  contain  data for each cross-over and totals for
     each leg, respectively. xinit will create these two files in
     the current directory, and write out the fileheader with a 1
     as the next record number in the case of xx_base.b. NB!  Any
     previous  files with the same names in the current directory
     will be erased, so use with caution.

     -I   Must be present form initialization to take effect.


     Both files are binary and have fixed recordlengths. The for-
     mats of the files are as follows:

     xx_base.b:
               Recordlength = 40 bytes.
               Rec # 1:       fileheader
               Rec # 2:       pairheader
               Next n recs:        crossover-structure
               Rec  #  n+3:        pairheader etc.
          The fileheader is a 40 byte character string where  the
          last  10  bytes  contains the record number of the last
          record in the file.  The pairheader is a 40 byte  char-
          acter  string  which contains the names of the two legs
          in question and the number of  COEs  generated  between
          them.   The crossover-structure contains all the infor-
          mation for one COE, that is lat, lon,  time  along  leg
          values  of  gravity,  magnetics,  and bathymetry at the
          cross-over point, the heading  of  track  #1,  and  the
          heading  of  track  #2.  See  program  listing for more
          details on formats. The file is sequential in that  new
          data are appended at the end of the file.

     xx_legs.b:
               Recordlength = 204 bytes.

          Each record contains the complete information for  each
          leg  that  has been checked. The leg-structure contains
          fields like year of  cruise,  no  of  internal/external
          COEs  for  gravity,  magnetics,  and  bathymetry, their
          means and standard deviations,  and  the  best  fitting
          regression  lines,  i.e.  the dc-shifts and drift-rates
          computed from the time/error data points.  See  program
          listing for complete description of record format.


SEE ALSO

     gmt(l), x_system(l)


REFERENCES

     Wessel, P. XOVER: A  Cross-over  Error  Detector  for  Track
     Data, Computers & Geosciences, 15, 333-346.