.TH X_LIST 1gmt "Feb 27 2014" "GMT 4.5.13 (SVN)" "Generic Mapping Tools"
.SH NAME
\fBx_list\fP \- Extract Cross-Over Information from the Data Base.
.SH SYNOPSIS
\fBx_list\fP [ \fIleg1\fP ] [ \fIleg2\fP ] [ \fB\-\fP\fIdataflags\fP ] 
[ \fB\-R\fP\fIwest/east/south/north\fP ] 
[ \fB\-X\fP\fIxbase\fP ] [ \fB\-H\fP ] [ \fB\-I\fP ] 
[ \fB\-V\fP ] [ \fB\-C\fP\fIcorrfile\fP ] [ \fB\-Z\fP\fIignorefile\fP ]
.SH DESCRIPTION
\fBx_list\fP will allow the user to extract information from the xx_base.b and xx_legs.b files.
Several options can be passed on the command line in order to specify which parameters to
extract. They are:
.TP
\fIleg1 leg2\fP
If two legs are specified, the cross-overs they have in common are returned.  If one leg is
specified, all the external cross-overs involving this leg are returned, OR only its internal
cross-overs if \-I is selected.  If no legs are given, all the external (or internal with \-I)
cross-overs are returned.  This program is useful if one wants to look at, say, gravity COEs versus
time from port for a particular leg, etc.
.TP
\fIdataflags\fP
This is a string of any combination of the following:
.br
	\fBl\fP means list both legnames.
.br
	\fBt\fP means list time.
.br
	\fBx\fP means list longitude.
.br
	\fBy\fP means list latitude.
.br
	\fBg\fP means list gravity COEs.
.br
	\fBm\fP means list magnetics COEs.
.br
	\fBb\fP means list bathymetry COEs.
.br
	\fBG\fP means list average gravity at cross-over.
.br
	\fBM\fP means list average magnetic anomaly at cross-over.
.br
	\fBB\fP means list average bathymetry at cross-over.
.br
	\fBh\fP means list heading of ship at cross-over.
.br
The components are written out in the order they appear in \fIdataflags\fP. The default output is
\fB\-txygmbGMBhl\fP.  When internal COEs are desired, the time reported is the elapsed time since
the ship first occupied the cross-over point. For external COEs the time means time from the start
of the year in seconds.
.TP
\fB\-R\fP
Only return cross-overs inside the specified region \fIwest, east, south, \fPand \fInorth\fP.  [Default is world].
.TP
\fB\-X\fP
Indicate alternate \fIxx_base.b\fP file.
.TP
\fB\-H\fP
Issue one header record on output.
.TP
\fB\-I\fP
Report on internal COEs [Default is external COEs].
.TP
\fB\-C\fP
Apply cross-over correction to the data (i.e., reports the cross-over value after the best-fitting
corrections have been applied to both legs). If no \fIcorrfile\fP is given, the default correction file
is assumed.
.TP
\fB\-Z\fP
Ignore those legs that appear in the \fIignorefile\fP.
.TP
\fB\-V\fP
Selects verbose mode, which will send progress reports to stderr [Default runs "silently"].
.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.