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.