NAME
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 ses-
sion.
-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 uselegs-
file 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.
BEWARE
The reason for the -M option is that if the COEs are few, then a sta-
ble 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 com-
puted. Conventional wisdom recommends plotting the time-series and the
computed regression line to see if it makes sense.
SEE ALSO
gmt(GMTMANSECTION), x_system(GMTMANSECTION)
REFERENCES
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