NAME

     XLIST - To extract  Cross-Over  Information  from  the  Data
     Base.


SYNOPSIS

     xlist   [   leg1   ]   [   leg2   ]   [   -dataflags   ]   [
     -Rwest/east/south/north ] [ -Xxbase ] [ -H ] [ -I ] [ -V ] [
     -Ccorrfile ] [ -Zignorefile ]


DESCRIPTION

     xlist will allow the user to extract  information  from  the
     xx_base.b  and  xx_legs.b  files.   Several  options  can be
     passed on the command line in order to specify which parame-
     ters to extract. They are:

     leg1 leg2
          If two legs are specified, the cross-overs they have in
          common  are returned.  If one leg is specified, all the
          external cross-overs involving this leg  are  returned,
          OR only its internal cross-overs if -I is selected.  If
          no legs are given, all the external (or  internal  with
          -I)  cross-overs  are returned.  This program is useful
          if one wants to look at, say, gravity COEs versus  time
          from port for a particular leg etc.

     dataflags
          This is a string of any combination of the following:
               l means list both legnames.
               t means list time.
               x means list longitude
               y means list latitude.
               g means list gravity COEs.
               m means list magnetics COEs.
               b means list bathymetry COEs.
               G means list average gravity at cross-over.
               M means list average magnetic  anomaly  at  cross-
          over.
               B means list average bathymetry at cross-over.
               h means list heading of ship at cross-over.
          The components are written out in the order they appear
          in dataflags. The default output is -txygmbGMBhl.  When
          internal COEs are desired, the  time  reported  is  the
          elapsed  time  since the ship first occupied the cross-
          over point. For external COEs the time means time  from
          the start of the year in seconds.

     -R   Only return cross-overs  inside  the  specified  region
          west, east, south, and north.  [Default is world].

     -X   Indicate alternate xx_base.b file.

     -H   Issue one header record on output.
     -I   Report on internal COEs [Default is external COEs].

     -C   Apply cross-over correction to the data  (i.e.  reports
          the cross-over value after the best-fitting corrections
          have been applied to both  legs).  If  no  corrfile  is
          given, the default correction file is assumed.

     -Z   Ignore those legs that appear in the ignorefile.

     -V   Operate in verbose mode.


SEE ALSO

     gmt(l), x_system(l)


REFERENCES

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