

 
Manual Reference Pages  X_SOLVE_DC_DRIFT (1)
NAME
x_solve_dc_drift  Find Bestfitting D.C.shift and Drift Estimates
CONTENTS
Synopsis
Description
Beware
See Also
References
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 bestfitting
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 crossovers.

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 x_list and gmtlist).

A

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

V

Selects verbose mode, which will send progress reports to stderr [Default runs "silently"].


BEWARE
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 COEs do occur near the ports so that a drift estimate can be computed.
Conventional wisdom recommends plotting the timeseries and the computed regression line to
see if it makes sense.
SEE ALSO
GMT(1),
x_system(1)
REFERENCES
Wessel, P. XOVER: A Crossover Error Detector for Track Data,
Computers & Geosciences, 15, 333346.
GMT 4.5.14  X_SOLVE_DC_DRIFT (1)  1 Nov 2015 
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