1X2SYS_DATALIST(1) GMT X2SYS_DATALIST(1)
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6 x2sys_datalist - Extract content of track data files
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9 x2sys_datalist track(s) -TTAG [ -A ] [ -E ] [ -Fname1,name2,... ] [
10 -I[list] ] [ -L[corrtable] ] [ -Rregion ] [ -S ] [ [ -V[level] ] [
11 -bobinary ] [ -donodata ] [ -hheaders ]
12 Note: No space is allowed between the option flag and the associated
14 arguments.
15
17 x2sys_datalist reads one or more files and produces a single ASCII [or
18 binary] table. The files can be of any format, which must be described
19 and passed with the -T option. You may limit the output to a geo‐
20 graphic region, and insist that the output from several files be sepa‐
21 rated by a multiple segment header. Only the named data fields will be
22 output [Default selects all columns].
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25 tracks Can be one or more ASCII, native binary, or COARDS netCDF 1-D
26 data files. To supply the data files via a text file with a list
27 of tracks (one per record), specify the name of the track list
28 after a leading equal-sign (e.g., =tracks.lis). If the names are
29 missing their file extension we will append the suffix specified
30 for this TAG. Track files will be searched for first in the cur‐
31 rent directory and second in all directories listed in
32 $X2SYS_HOME/TAG/TAG_paths.txt (if it exists). [If $X2SYS_HOME is
33 not set it will default to $GMT_SHAREDIR/x2sys]. (Note: MGD77
34 files will also be looked for via MGD77_HOME/mgd77_paths.txt and
35 *.gmt files will be searched for via $GMT_SHAREDIR/mgg/gmt‐
36 file_paths).
37 -TTAG Specify the x2sys TAG which tracks the attributes of this data
39 type.
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42 -A Eliminate COEs by distributing the COE between the two tracks in
43 proportion to track weight. These (dist, adjustment) spline
44 knots files for each track and data column are called track.col‐
45 umn.adj and are expected to be in the $X2SYS_HOME/TAG directory.
46 The adjustments are only applied if the corresponding adjust
47 file can be found [No residual adjustments]
48 -E Enhance ASCII output by writing GMT segment headers between data
50 from each track [no segment headers].
51 -Fname1,name2,...
53 Give a comma-separated sub-set list of column names defined in
54 the definition file. [Default selects all data columns].
55 -I[list]
57 Name of ASCII file with a list of track names (one per record)
58 that should be excluded from consideration [Default includes all
59 tracks].
60 -L[corrtable]
62 Apply optimal corrections to columns where such corrections are
63 available. Append the correction table to use [Default uses the
64 correction table TAG_corrections.txt which is expected to reside
65 in the $X2SYS_HOME/TAG directory]. For the format of this file,
66 see CORRECTIONS below.
67 -Rwest/east/south/north[/zmin/zmax][+r][+uunit]
69 west, east, south, and north specify the region of interest, and
70 you may specify them in decimal degrees or in
71 [±]dd:mm[:ss.xxx][W|E|S|N] format Append +r if lower left and
72 upper right map coordinates are given instead of w/e/s/n. The
73 two shorthands -Rg and -Rd stand for global domain (0/360 and
74 -180/+180 in longitude respectively, with -90/+90 in latitude).
75 Alternatively for grid creation, give Rcodelon/lat/nx/ny, where
76 code is a 2-character combination of L, C, R (for left, center,
77 or right) and T, M, B for top, middle, or bottom. e.g., BL for
78 lower left. This indicates which point on a rectangular region
79 the lon/lat coordinate refers to, and the grid dimensions nx and
80 ny with grid spacings via -I is used to create the corresponding
81 region. Alternatively, specify the name of an existing grid
82 file and the -R settings (and grid spacing, if applicable) are
83 copied from the grid. Appending +uunit expects projected (Carte‐
84 sian) coordinates compatible with chosen -J and we inversely
85 project to determine actual rectangular geographic region. For
86 perspective view (-p), optionally append /zmin/zmax. In case of
87 perspective view (-p), a z-range (zmin, zmax) can be appended to
88 indicate the third dimension. This needs to be done only when
89 using the -Jz option, not when using only the -p option. In the
90 latter case a perspective view of the plane is plotted, with no
91 third dimension. For Cartesian data just give
92 xmin/xmax/ymin/ymax. This option limits the COEs to those that
93 fall inside the specified domain.
94 -S Suppress output records where all the data columns are NaN
96 [Default will output all records].
97 -V[level] (more ...)
99 Select verbosity level [c].
100 -bo[ncols][type] (more ...)
102 Select native binary output.
103 -donodata (more ...)
105 Replace output columns that equal NaN with nodata.
106 -h[i|o][n][+c][+d][+rremark][+rtitle] (more ...)
108 Skip or produce header record(s).
109 -^ or just -
111 Print a short message about the syntax of the command, then
112 exits (NOTE: on Windows just use -).
113 -+ or just +
115 Print an extensive usage (help) message, including the explana‐
116 tion of any module-specific option (but not the GMT common
117 options), then exits.
118 -? or no arguments
120 Print a complete usage (help) message, including the explanation
121 of all options, then exits.
122
124 To extract all data from the old-style MGG supplement file c2104.gmt,
125 recognized by the tag GMT:
126 gmt x2sys_datalist c2104.gmt -TGMT > myfile
128 To make lon,lat, and depth input for blockmean and surface using all
130 the files listed in the file tracks.lis and define by the tag TRK, but
131 only the data that are inside the specified area, and make output
132 binary, run
133 gmt x2sys_datalist =tracks.lis -TTRK -Fon,lat,depth -R40/-30/25/35 -bo > alltopo_bin.xyz
135
137 The correction table is an ASCII file with coefficients and parameters
138 needed to carry out corrections. This table is usually produced by
139 x2sys_solve. Comment records beginning with # are allowed. All correc‐
140 tion records are of the form
141 trackID observation correction
143 where trackID is the track name, observation is one of the abbrevia‐
145 tions for an observed field contained in files under this TAG, and cor‐
146 rection consists of one or more white-space-separated terms that will
147 be subtracted from the observation before output. Each term must have
148 this exact syntax:
149 factor[*[function]([scale](abbrev[-origin]))[^power]]
151 where terms in brackets are optional (the brackets themselves are not
153 used but regular parentheses must be used exactly as indicated). No
154 spaces are allowed except between terms. The factor is the amplitude of
155 the basis function, while the optional function can be one of sin, cos,
156 or exp. The optional scale and origin can be used to translate the
157 argument (before giving it to the optional function). The argument
158 abbrev is one of the abbreviations for columns known to this TAG. How‐
159 ever, it can also be one of the three auxiliary terms dist (for
160 along-track distances), azim for along-track azimuths, and vel (for
161 along-track speed); these are all sensitive to the -C and -N settings
162 used when defining the TAB; furthermore, vel requires time to be
163 present in the data. If origin is given as T it means that we should
164 replace it with the value of abbrev for the very first record in the
165 file (this is usually only done for time). If the first data record
166 entry is NaN we revert origin to zero. Optionally, raise the entire
167 expression to the given power, before multiplying by factor. The fol‐
168 lowing is an example of fictitious corrections to the track ABC, imply‐
169 ing the z column should have a linear trend removed, the field obs
170 should be corrected by a strange dependency on latitude, weight needs
171 to have 1 added (hence correction is given as -1), and fuel should be
172 reduced by a linear distance term:
173 ABC z 7.1 1e-4*((time-T))
175 ABC obs 0.5*exp(-1e-3(lat))^1.5
177 ABC weight -1
179 ABC fuel 0.02*((dist))
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183 blockmean, gmt, surface, x2sys_init, x2sys_datalist, x2sys_get,
184 x2sys_list, x2sys_put, x2sys_report, x2sys_solve
185
187 2019, P. Wessel, W. H. F. Smith, R. Scharroo, J. Luis, and F. Wobbe
1885.4.5 Feb 24, 2019 X2SYS_DATALIST(1)