.TH X_INIT 1gmt "Feb 27 2014" "GMT 4.5.13 (SVN)" "Generic Mapping Tools"
.SH NAME
\fBx_init\fP \- Initialization of Cross-Over Data Bases.
.SH SYNOPSIS
\fBx_init\fP \fB\-I\fP
.SH DESCRIPTION
The purpose of \fBx_init\fP is to create two key files that will be holding all the cross-over
information for all the cruises tested. These files are called \fIxx_base.b\fP and \fIxx_legs.b\fP, and
they will contain data for each cross-over and totals for each leg, respectively. 
\fBx_init\fP 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.
.TP
\fB\-I\fP
Must be present form initialization to take effect.
.SH BEWARE
Both files are binary and have fixed record lengths. The formats of the files are as follows:
.br
.TP
.B xx_base.b:
	Record length = 40 bytes.
.br
	Rec # 1:		fileheader
.br
	Rec # 2:		pairheader
.br
	Next n recs:		crossover-structure
.br
	Rec  #  n+3:		pairheader etc.
.br
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.
.TP
.B xx_legs.b:
	Record length = 204 bytes.
.br
.sp
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.
.br
.SH SEE ALSO
.IR GMT (1),
.IR x_system (1)
.SH REFERENCES
Wessel, P. XOVER: A Cross-over Error Detector for Track Data,
\fIComputers & Geosciences, 15\fP, 333-346.