## NAME

           x_update - Archiving of Cross-Over Information

## SYNOPSIS

           x_update cross-overfile [ -Xxbase ] [ -Llegbase ] [ -V ] [
           -Wmax ]

## DESCRIPTION

           x_update reads the  ASCII  file  produced  by  x_over  and
           writes the information to the database files xx_base.b and
           xx_legs.b (unless other filenames  are  specified  on  the
           command  line) using a compact, binary format. The options
           recognized are:

           -X     Indicate alternate xx_base.b file.

           -L     Indicate alternate xx_legs.b file.

           -V     Verbose. Reports  the  pair  currently  being  pro
                  cessed.

           -W     Prints a warning if the number of COEs generated by
                  any pair of legs exceed max.

## For security reasons the xx_legs.b are first renamed to

           xx_legs.b_old, to prevent loss of
           information  if  a  black-out or system crash should occur
           during writing of the new xx_legs.b  file.  It  is  recom
           mended  that  the  old file is left on the disk in case of
           other disasters. Note that x_update does not  check  if  a
           pair  of  legs  already exist in the xx_base.b file. It is
           the user's' responsibility to ensure that  duplication  of
           information  does  not occur. Should some pairs already in
           the database need to be  re-examined,  then  run  x_remove
           which  will  wipe  out all traces of the specified cruises
           from the x_system data base files. Now  we  can  pass  the
           pairs  that  need  to  be  redone  through x_over/x_update
           again.

## SEE ALSO

           gmt(l), x_system(l)

## REFERENCES

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

                               15 Oct 2001                x_update(l)