x2sys_datalist
x2sys_datalist - Extract content of track data files
Synopsis
x2sys_datalist track(s) -TTAG
[ -A ]
[ -E ]
[ -Fname1,name2,...) ]
[ -I[list] ]
[ -L[corrtable] ]
[ -Rregion ]
[ -S ] [
[ -V[level] ]
[ -bo<binary> ]
[ -do<nodata> ]
[ -h<headers> ]
Note: No space is allowed between the option flag and the associated arguments.
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].
Required Arguments
- 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).
- -TTAG
- Specify the x2sys TAG which tracks the attributes of this data type.
Optional 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]
- -E
- Enhance ASCII output by writing GMT segment headers between data
from each track [no segment headers].
- -Fname1,name2,...)
- Give a comma-separated sub-set list of column names defined in the
definition file. [Default selects all data columns].
- -I[list]
- Name of ASCII file with a list of track names (one per record) that
should be excluded from consideration [Default includes all tracks].
- -L[corrtable]
- 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[unit]west/east/south/north[/zmin/zmax][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 for grid creation, give Rcodelon/lat/nx/ny, where
code is a 2-character combination of L, C, R (for left, center, or right)
and T, M, B for top, middle, or bottom. e.g., BL for lower left. This
indicates which point on a rectangular region the lon/lat coordinate
refers to, and the grid dimensions nx and ny with grid spacings via
-I is used to create the corresponding region.
Alternatively, specify the name of an existing grid file and the
-R settings (and grid spacing, if applicable) are copied from
the grid. Using -Runit expects projected (Cartesian)
coordinates compatible with chosen -J and we inversely project
to determine actual rectangular geographic region.
For perspective view (-p), optionally append /zmin/zmax.
In case of perspective view (-p), a z-range (zmin, zmax)
can be appended to indicate the third dimension. This needs to be
done only when using the -Jz option, not when using only the
-p option. In the latter case a perspective view of the plane is
plotted, with no third dimension. 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[level] (more ...)
- Select verbosity level [c].
- -bo[ncols][type] (more ...)
- Select native binary output.
- -donodata (more ...)
- Replace output columns that equal NaN with nodata.
- -h[i|o][n][+c][+d][+rremark][+rtitle] (more ...)
- Skip or produce header record(s).
- -^ or just -
- Print a short message about the syntax of the command, then exits (NOTE: on Windows use just -).
- -+ or just +
- Print an extensive usage (help) message, including the explanation of
any module-specific option (but not the GMT common options), then exits.
- -? or no arguments
- Print a complete usage (help) message, including the explanation of
options, then exits.
- --version
- Print GMT version and exit.
- --show-datadir
- Print full path to GMT share directory and exit.
Examples
To extract all data from the old-style MGG supplement file c2104.gmt,
recognized by the tag GMT:
gmt x2sys_datalist c2104.gmt -TGMT > 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
gmt x2sys_datalist =tracks.lis -TTRK -Fon,lat,depth -R40/-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))