x_solve_dc_drift

       x_solve_dc_drift  - Find Best-fitting D.C.-shift and Drift
       Estimates

SYNOPSIS

       x_solve_dc_drift [ -Xxbase ] [ -Llbase ] [ -Iignorefile  ]
       [    -S    ]    [   -Citeration   ]   [   -Mmin_nx   ]   [
       -Rwest/east/south/north ] [  -Uuselegsfile  ]  [  -V  ]  [
       -Bbinfile ] [ -AASCIIfile ]

DESCRIPTION

       x_solve_dc_drift  will  read  the  database  files and, by
       iterating, find the best-fitting regression  line  to  the
       <time,COE>  points for each leg that minimizes the overall
       standard deviation of the data  set  in  a  least  squares
       sense. Finally, correction file(s) are created.

       -X     Indicate an alternate database to read. [Default is
              xx_base.b].

       -L     Indicate an alternate legbase to read. [Default  is
              xx_legs.b].

       -I     Ignore  information for certain legs (that might be
              bad etc).

       -S     Reset the old d.c.-shift  and  drift  estimates  to
              zero before iterating.

       -C     Specify  how  many  iterations  to  do.  Default is
              interactive session.

       -M     Solve for drift only  if  the  leg  has  more  than
              min_nx cross-overs.

       -R     Only  take  COEs  inside  this region into account.
              [Default is world].

       -U     Solve for corrections involving COEs from  legs  in
              the uselegsfile only.

       -B     Create  a binary correction file (which can be read
              by xlist and gmtlist).

       -A     Create an ASCII correction table. At least  one  of
              -A and -B must be specified.

       -V     Operate in verbose mode.

The reason for the -M option is that if the COEs are few, then a

       stable estimate of the slope may
       not be obtained (e.g. when most of the COEs  occur  midway
       between  ports).  However,  in  most cases the bulk of the
       time-series and the computed regression line to see if  it
       makes sense.

SEE ALSO

       gmt(l), x_system(l)

REFERENCES

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