NAME¶
x2sys_datalist - A generic data-extractor for ASCII or binary files
SYNOPSIS¶
x2sys_datalist track(s) -TTAG [
-A ] [
-F name1,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)