Provided by: gmt_4.5.11-1build1_amd64 
NAME
x_init - Initialization of Cross-Over Data Bases.
SYNOPSIS
x_init -I
DESCRIPTION
The purpose of x_init 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. x_init 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.
BEWARE
Both files are binary and have fixed record lengths. The formats of the files are as follows:
xx_base.b:
Record length = 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 character 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 information 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:
Record length = 204 bytes.
Each record contains the complete information for each leg that has been checked. The leg-
structure contains fields like year of cruise, number 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(1), x_system(1)
REFERENCES
Wessel, P. XOVER: A Cross-over Error Detector for Track Data, Computers & Geosciences, 15, 333-346.