1X2SYS_LIST(1) Generic Mapping Tools X2SYS_LIST(1)
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6 x2sys_list - Output a subset of crossovers from data base
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9 x2sys_list -Ccolumn -TTAG [ coedbase.txt ] [ -Aasymm_max ] [ -FacdhiIn‐
10 NtTvxyz ] [ -I[list] ] [ -L[corrtable] ] [ -Nnx_min ] [ -Qe|i ] [
11 -Rwest/east/south/north[r] ] [ -Strack ] [ -V ] [ -W[list] ] [
12 -bo[s|S|d|D[ncol]|c[var1/...]] ] [ -m[flag] ]
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15 x2sys_list will read the crossover ASCII data base coedbase.txt (or
16 stdin) and extract a subset of the crossovers based on the other argu‐
17 ments. The output may be ASCII or binary.
18 -C Specify which data column you want to process. Crossovers
20 related to this column name must be present in the crossover
21 data base.
22 -T Specify the x2sys TAG which tracks the attributes of this data
24 type.
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27 No space between the option flag and the associated arguments.
28 coedbase.txt
30 The name of the input ASCII crossover error data base as pro‐
31 duced by x2sys_cross. If not given we read standard input
32 instead.
33 -A Specifies maximum asymmetry in the distribution of crossovers
35 relative to the mid point in time (or distance, if not time is
36 available). Asymmetry is computed as (n_right -
37 n_left)/(n_right + n_left), referring the the number of
38 crossovers that falls in the left or right half of the range.
39 Symmetric distributions will have values close to zero. If
40 specified, we exclude tracks whose asymmetry exceeds the specify
41 cutoff in absolute value [1, i.e., include all].
42 -F Specify your desired output using any combination of acdhiIn‐
44 NtTvwxyz, in any order. Do not use space between the letters,
45 and note your selection is case-sensitive. The output will be
46 ASCII (or binary, see -bo) columns of values. Description of
47 codes: a is the angle (< 90) defined by the crossing tracks, c
48 is crossover value of chosen observation (see -C), d is distance
49 along track, h is heading along track, i is the signed time
50 interval between the visit at the crossover of the two tracks
51 involved, I is same as i but is unsigned, n is the names of the
52 two tracks, N is the id numbers of the two tracks, t is time
53 along track in dateTclock format (NaN if not available), T is
54 elapsed time since start of track along track (NaN if not avail‐
55 able), v is speed along track, w is the composite weight, x is
56 x-coordinate (or longitude), y is y-coordinate (or latitude),
57 and z is observed value (see -C) along track. If -S is not
58 specified then d,h,n,N,t,T,v results in two output columns each:
59 first for track one and next for track two (in lexical order of
60 track names); otherwise, they refer to the specified track only
61 (except for n,N which then refers to the other track). The sign
62 convention for c,i is track one minus track two (lexically
63 sorted). Time intervals will be returned according to the
64 TIME_UNIT GMT defaults setting.
65 -I Name of ASCII file with a list of track names (one per record)
67 that should be excluded from consideration [Default includes all
68 tracks].
69 -L Apply optimal corrections to the chosen observable. Append the
71 correction table to use [Default uses the correction table
72 TAG_corrections.txt which is expected to reside in the
73 $X2SYS_HOME/TAG directory]. For the format of this file, see
74 x2sys_solve.
75 -N Only report data from pairs that generated at least nx_min
77 crossovers between them [use all pairs].
78 -Q Append e for external crossovers or i for internal crossovers
80 only [Default is all crossovers].
81 -R west, east, south, and north specify the Region of interest, and
83 you may specify them in decimal degrees or in
84 [+-]dd:mm[:ss.xxx][W|E|S|N] format. Append r if lower left and
85 upper right map coordinates are given instead of w/e/s/n. The
86 two shorthands -Rg and -Rd stand for global domain (0/360 and
87 -180/+180 in longitude respectively, with -90/+90 in latitude).
88 Alternatively, specify the name of an existing grid file and the
89 -R settings (and grid spacing, if applicable) are copied from
90 the grid. For Cartesian data just give xmin/xmax/ymin/ymax.
91 This option limits the COEs to those that fall inside the speci‐
92 fied domain.
93 -S Name of a single track. If given we restrict output to those
95 crossovers involving this track [Default output is crossovers
96 involving any track pair]. Prepend a '+' to make it print info
97 relative to both tracks [Default is selected track]. This
98 applies only to comon information such as distance, time, head‐
99 ing.
100 -V Selects verbose mode, which will send progress reports to stderr
102 [Default runs "silently"].
103 -W Name of ASCII file with a list of track names and their relative
105 weights (one track per record) that should be used to calculate
106 the composite crossover weight (output code w above). [Default
107 sets weights to 1].
108 -bo Selects binary output. Append s for single precision [Default
110 is d (double)]. Uppercase S or D will force byte-swapping.
111 Optionally, append ncol, the number of desired columns in your
112 binary output file.
113 -m Multiple segment output format. Segments with crossovers for a
115 single track pair are separated by a record whose first charac‐
116 ter is flag and contains the two track names. [Default is '>'].
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119 To find all the magnetic crossovers associated with the tag MGD77 from
120 the file COE_data.txt, restricted to occupy a certain region in the
121 south Pacific, and return location, time, and crossover value, try
122 x2sys_list COE_data.txt -V -TMGD77 -R180/240/-60/-30 -Cmag -Fxytz >
124 mag_coe.txt
125 To find all the faa crossovers globally that involves track 12345678
127 and output time since start of the year, using a binary double preci‐
128 sion format, try
129 x2sys_list COE_data.txt -V -TMGD77 -Cfaa -S12345678 -FTz -bod >
131 faa_coe.b
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134 x2sys_binlist(1), x2sys_cross(1), x2sys_datalist(1), x2sys_get(1),
135 x2sys_init(1), x2sys_put(1), x2sys_report(1), x2sys_solve(1)
136GMT 4.5.6 10 Mar 2011 X2SYS_LIST(1)