Provided by: gmt_4.5.11-1build1_amd64 
NAME
x2sys_datalist - A generic data-extractor for ASCII or binary files
SYNOPSIS
x2sys_datalist track(s) -TTAG [ -A ] [ -Fname1,name2,... ] [ -H[i][nrec] ] [ -L[corrtable] ] [
-Rwest/east/south/north[r] ] [ -S ] [ -V ] [ -bo[s|S|d|D[ncol]|c[var1/...]] ] [ -m[flag] ]
DESCRIPTION
x2sys_datalist reads one or more files and produces a single ASCII [or binary] table. The files can be
of any format, which must be described and passed with the -T option. You may limit the output to a
geographic region, and insist that the output from several files be separated by a multiple segment
header. Only the named data fields will be output [Default selects all columns].
tracks Can be one or more ASCII, native binary, or COARDS netCDF 1-D data files. To supply the data
files via a text file with a list of tracks (one per record), specify the name of the track list
after a leading equal-sign (e.g., =tracks.lis). If the names are missing their file extension we
will append the suffix specified for this TAG. Track files will be searched for first in the
current directory and second in all directories listed in $X2SYS_HOME/TAG/TAG_paths.txt (if it
exists). [If $X2SYS_HOME is not set it will default to $GMT_SHAREDIR/x2sys]. (Note: MGD77 files
will also be looked for via MGD77_HOME/mgd77_paths.txt and *.gmt files will be searched for via
$GMT_SHAREDIR/mgg/gmtfile_paths).
-T Specify the x2sys TAG which tracks the attributes of this data type.
OPTIONS
No space between the option flag and the associated arguments.
-A Eliminate COEs by distributing the COE between the two tracks in proportion to track weight.
These (dist, adjustment) spline knots files for each track and data column are called
track.column.adj and are expected to be in the $X2SYS_HOME/TAG directory. The adjustments are
only applied if the corresponding adjust file can be found [No residual adjustments]
-F Give a comma-separated sub-set list of column names defined in the definition file. [Default
selects all data columns].
-H Input file(s) has header record(s). If used, the default number of header records is
N_HEADER_RECS. Use -Hi if only input data should have header records [Default will write out
header records if the input data have them]. Blank lines and lines starting with # are always
skipped.
-L Apply optimal corrections to columns where such corrections are available. Append the correction
table to use [Default uses the correction table TAG_corrections.txt which is expected to reside in
the $X2SYS_HOME/TAG directory]. For the format of this file, see CORRECTIONS below.
-R west, east, south, and north specify the Region of interest, and you may specify them in decimal
degrees or in [+-]dd:mm[:ss.xxx][W|E|S|N] format. Append r if lower left and upper right map
coordinates are given instead of w/e/s/n. The two shorthands -Rg and -Rd stand for global domain
(0/360 and -180/+180 in longitude respectively, with -90/+90 in latitude). Alternatively, specify
the name of an existing grid file and the -R settings (and grid spacing, if applicable) are copied
from the grid. For Cartesian data just give xmin/xmax/ymin/ymax. This option limits the COEs to
those that fall inside the specified domain.
-S Suppress output records where all the data columns are NaN [Default will output all records].
-V Selects verbose mode, which will send progress reports to stderr [Default runs "silently"].
-bo Selects binary output. Append s for single precision [Default is d (double)]. Uppercase S or D
will force byte-swapping. Optionally, append ncol, the number of desired columns in your binary
output file.
-m Output a multisegment header between data from each track. Note this option does not imply
anything about the input file; that information is conveyed via the system tag (-T).
EXAMPLES
To extract all data from the old-style MGG supplement file c2104.gmt, recognized by the tag GMT:
x2sys_datalist c2104.gmt -T GMT > myfile
To make lon,lat, and depth input for blockmean and surface using all the files listed in the file
tracks.lis and define by the tag TRK, but only the data that are inside the specified area, and make
output binary, run
x2sys_datalist =tracks.lis -T TRK -F lon,lat,depth -R-40/-30/25/35 -bo > alltopo_bin.xyz
CORRECTIONS
The correction table is an ASCII file with coefficients and parameters needed to carry out corrections.
This table is usually produced by x2sys_solve. Comment records beginning with # are allowed. All
correction records are of the form
trackID observation correction
where trackID is the track name, observation is one of the abbreviations for an observed field contained
in files under this TAG, and correction consists of one or more white-space-separated terms that will be
subtracted from the observation before output. Each term must have this exact syntax:
factor[*[function]([scale](abbrev[-origin]))[^power]]
where terms in brackets are optional (the brackets themselves are not used but regular parentheses must
be used exactly as indicated). No spaces are allowed except between terms. The factor is the amplitude
of the basis function, while the optional function can be one of sin, cos, or exp. The optional scale and
origin can be used to translate the argument (before giving it to the optional function). The argument
abbrev is one of the abbreviations for columns known to this TAG. However, it can also be one of the
three auxiliary terms dist (for along-track distances), azim for along-track azimuths, and vel (for
along-track speed); these are all sensitive to the -C and -N settings used when defining the TAB;
furthermore, vel requires time to be present in the data. If origin is given as T it means that we
should replace it with the value of abbrev for the very first record in the file (this is usually only
done for time). If the first data record entry is NaN we revert origin to zero. Optionally, raise the
entire expression to the given power, before multiplying by factor. The following is an example of
fictitious corrections to the track ABC, implying the z column should have a linear trend removed, the
field obs should be corrected by a strange dependency on latitude, weight needs to have 1 added (hence
correction is given as -1), and fuel should be reduced by a linear distance term:
ABC z 7.1 1e-4*((time-T))
ABC obs 0.5*exp(-1e-3(lat))^1.5
ABC weight -1
ABC fuel 0.02*((dist))
SEE ALSO
blockmean(1), GMT(1), surface(1), x2sys_init(1), x2sys_datalist(1), x2sys_get(1), x2sys_list(1),
x2sys_put(1), x2sys_report(1), x2sys_solve(1)
GMT 4.5.11 5 Nov 2013 X2SYS_DATALIST(1gmt)