X_INIT(1) Generic Mapping Tools X_INIT(1)NAMEx_init - Initialization of Cross-Over Data Bases.
SYNOPSISx_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 gener‐
ated 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 pro‐
gram 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 ALSOGMT(1), x_system(1)REFERENCES
Wessel, P. XOVER: A Cross-over Error Detector for Track Data, Computers
& Geosciences, 15, 333-346.
GMT 4.5.14 1 Nov 2015 X_INIT(1)
