NAME
XINIT - Initialization of Cross-Over Data Bases.
SYNOPSIS
xinit -I
DESCRIPTION
The purpose of xinit is to create two key files that will be
holding all the cross-over information for all the cruises
tested. These files are called xx_base.b and xx_legs.b, and
they will contain data for each cross-over and totals for
each leg, respectively. xinit will create these two files in
the current directory, and write out the fileheader with a 1
as the next record number in the case of xx_base.b. NB! Any
previous files with the same names in the current directory
will be erased, so use with caution.
-I Must be present form initialization to take effect.
Both files are binary and have fixed recordlengths. The for-
mats of the files are as follows:
xx_base.b:
Recordlength = 40 bytes.
Rec # 1: fileheader
Rec # 2: pairheader
Next n recs: crossover-structure
Rec # n+3: pairheader etc.
The fileheader is a 40 byte character string where the
last 10 bytes contains the record number of the last
record in the file. The pairheader is a 40 byte char-
acter string which contains the names of the two legs
in question and the number of COEs generated between
them. The crossover-structure contains all the infor-
mation for one COE, that is lat, lon, time along leg
values of gravity, magnetics, and bathymetry at the
cross-over point, the heading of track #1, and the
heading of track #2. See program listing for more
details on formats. The file is sequential in that new
data are appended at the end of the file.
xx_legs.b:
Recordlength = 204 bytes.
Each record contains the complete information for each
leg that has been checked. The leg-structure contains
fields like year of cruise, no of internal/external
COEs for gravity, magnetics, and bathymetry, their
means and standard deviations, and the best fitting
regression lines, i.e. the dc-shifts and drift-rates
computed from the time/error data points. See program
listing for complete description of record format.
SEE ALSO
gmt(l), x_system(l)
REFERENCES
Wessel, P. XOVER: A Cross-over Error Detector for Track
Data, Computers & Geosciences, 15, 333-346.