X_LIST

x_list − Extract Cross-Over Information from the Data Base.

x_list [ leg1 ] [ leg2 ] [ −dataflags ] [ −Rwest/east/south/north ] [ −Xxbase ] [ −H ] [ −I ] [ −V ] [ −Ccorrfile ] [ −Zignorefile ]

x_list 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:

leg1 leg2

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.

dataflags

This is a string of any combination of the following:

l means list both legnames.

t means list time.

x means list longitude.

y means list latitude.

g means list gravity COEs.

m means list magnetics COEs.

b means list bathymetry COEs.

G means list average gravity at cross-over.

M means list average magnetic anomaly at cross-over.

B means list average bathymetry at cross-over.

h means list heading of ship at cross-over.

The components are written out in the order they appear in dataflags. The default output is −txygmbGMBhl. 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.

−R

Only return cross-overs inside the specified region west, east, south, and north. [Default is world].

−X

Indicate alternate xx_base.b file.

−H

Issue one header record on output.

−I

Report on internal COEs [Default is external COEs].

−C

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 corrfile is given, the default correction file is assumed.

−Z

Ignore those legs that appear in the ignorefile.

−V

Operate in verbose mode.

GMT(l), x_system(l)

Wessel, P. XOVER: A Cross-over Error Detector for Track Data, Computers & Geosciences, 15, 333-346.