1X2SYS_LIST(1) GMT X2SYS_LIST(1)
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6 x2sys_list - Extract subset from crossover data base
7
9 x2sys_list -Ccolumn -TTAG [ coedbase.txt ] [ -Aasymm_max ] [ -E ] [
10 -FacdhiInNtTvwxyz ] [ -I[list] ] [ -L[corrtable] ] [ -Nnx_min ] [
11 -Qe|i ] [ -Rregion ] [ -Strack ] [ -V[level] ] [ -W[list] ] [
12 -bobinary ]
13 Note: No space is allowed between the option flag and the associated
15 arguments.
16
18 x2sys_list will read the crossover ASCII data base coedbase.txt (or
19 stdin) and extract a subset of the crossovers based on the other argu‐
20 ments. The output may be ASCII or binary.
21
23 -Ccolumn
24 Specify which data column you want to process. Crossovers
25 related to this column name must be present in the crossover
26 data base.
27 -TTAG Specify the x2sys TAG which tracks the attributes of this data
29 type.
30
32 coedbase.txt
33 The name of the input ASCII crossover error data base as pro‐
34 duced by x2sys_cross. If not given we read standard input
35 instead.
36 -Aasymm_max
38 Specifies maximum asymmetry in the distribution of crossovers
39 relative to the mid point in time (or distance, if not time is
40 available). Asymmetry is computed as (n_right - n_left)/(n_right
41 + n_left), referring the the number of crossovers that falls in
42 the left or right half of the range. Symmetric distributions
43 will have values close to zero. If specified, we exclude tracks
44 whose asymmetry exceeds the specify cutoff in absolute value [1,
45 i.e., include all].
46 -E Enhance ASCII output by writing GMT segment headers with name of
48 the two tracks and their total number of cross-overs [no segment
49 headers].
50 -FacdhiInNtTvwxyz
52 Specify your desired output using any combination of acdhiIn‐
53 NtTvwxyz, in any order. Do not use space between the letters,
54 and note your selection is case-sensitive. The output will be
55 ASCII (or binary, -bo) columns of values. Description of codes:
56 a is the angle (< 90) defined by the crossing tracks, c is
57 crossover value of chosen observation (see -C), d is distance
58 along track, h is heading along track, i is the signed time
59 interval between the visit at the crossover of the two tracks
60 involved, I is same as i but is unsigned, n is the names of the
61 two tracks, N is the id numbers of the two tracks, t is time
62 along track in dateTclock format (NaN if not available), T is
63 elapsed time since start of track along track (NaN if not avail‐
64 able), v is speed along track, w is the composite weight, x is
65 x-coordinate (or longitude), y is y-coordinate (or latitude),
66 and z is observed value (see -C) along track. If -S is not spec‐
67 ified then d,h,n,N,t,T,v results in two output columns each:
68 first for track one and next for track two (in lexical order of
69 track names); otherwise, they refer to the specified track only
70 (except for n,N which then refers to the other track). The sign
71 convention for c,i is track one minus track two (lexically
72 sorted). Time intervals will be returned according to the
73 TIME_UNIT GMT defaults setting.
74 -I[list]
76 Name of ASCII file with a list of track names (one per record)
77 that should be excluded from consideration [Default includes all
78 tracks].
79 -L[corrtable]
81 Apply optimal corrections to the chosen observable. Append the
82 correction table to use [Default uses the correction table
83 TAG_corrections.txt which is expected to reside in the
84 $X2SYS_HOME/TAG directory]. For the format of this file, see
85 x2sys_solve.
86 -Nnx_min
88 Only report data from pairs that generated at least nx_min
89 crossovers between them [use all pairs].
90 -Qe|i Append e for external crossovers or i for internal crossovers
92 only [Default is all crossovers].
93 -Rwest/east/south/north[/zmin/zmax][+r][+uunit]
95 west, east, south, and north specify the region of interest, and
96 you may specify them in decimal degrees or in
97 [±]dd:mm[:ss.xxx][W|E|S|N] format Append +r if lower left and
98 upper right map coordinates are given instead of w/e/s/n. The
99 two shorthands -Rg and -Rd stand for global domain (0/360 and
100 -180/+180 in longitude respectively, with -90/+90 in latitude).
101 Alternatively for grid creation, give Rcodelon/lat/nx/ny, where
102 code is a 2-character combination of L, C, R (for left, center,
103 or right) and T, M, B for top, middle, or bottom. e.g., BL for
104 lower left. This indicates which point on a rectangular region
105 the lon/lat coordinate refers to, and the grid dimensions nx and
106 ny with grid spacings via -I is used to create the corresponding
107 region. Alternatively, specify the name of an existing grid
108 file and the -R settings (and grid spacing, if applicable) are
109 copied from the grid. Appending +uunit expects projected (Carte‐
110 sian) coordinates compatible with chosen -J and we inversely
111 project to determine actual rectangular geographic region. For
112 perspective view (-p), optionally append /zmin/zmax. In case of
113 perspective view (-p), a z-range (zmin, zmax) can be appended to
114 indicate the third dimension. This needs to be done only when
115 using the -Jz option, not when using only the -p option. In the
116 latter case a perspective view of the plane is plotted, with no
117 third dimension. For Cartesian data just give
118 xmin/xmax/ymin/ymax. This option bases the statistics on those
119 COE that fall inside the specified domain.
120 -Strack
122 Name of a single track. If given we restrict output to those
123 crossovers involving this track [Default output is crossovers
124 involving any track pair].
125 -V[level] (more ...)
127 Select verbosity level [c].
128 -W[list]
130 Name of ASCII file with a list of track names and their relative
131 weights (one track per record) that should be used to calculate
132 the composite crossover weight (output code w above). [Default
133 sets weights to 1].
134 -bo[ncols][type] (more ...)
136 Select native binary output.
137 -^ or just -
139 Print a short message about the syntax of the command, then
140 exits (NOTE: on Windows just use -).
141 -+ or just +
143 Print an extensive usage (help) message, including the explana‐
144 tion of any module-specific option (but not the GMT common
145 options), then exits.
146 -? or no arguments
148 Print a complete usage (help) message, including the explanation
149 of all options, then exits.
150
152 To find all the magnetic crossovers associated with the tag MGD77 from
153 the file COE_data.txt, restricted to occupy a certain region in the
154 south Pacific, and return location, time, and crossover value, try
155 gmt x2sys_list COE_data.txt -V -TMGD77 -R180/240/-60/-30 -Cmag -Fxytz > mag_coe.txt
157 To find all the faa crossovers globally that involves track 12345678
159 and output time since start of the year, using a binary double preci‐
160 sion format, try
161 gmt x2sys_list COE_data.txt -V -TMGD77 -Cfaa -S12345678 -FTz -bod > faa_coe.b
163
165 x2sys_binlist, x2sys_cross, x2sys_datalist, x2sys_get, x2sys_init,
166 x2sys_put, x2sys_report, x2sys_solve
167
169 2019, P. Wessel, W. H. F. Smith, R. Scharroo, J. Luis, and F. Wobbe
1705.4.5 Feb 24, 2019 X2SYS_LIST(1)