x2sys_list - Extract subset from crossover data base
x2sys_list -Ccolumn -TTAG [
coedbase.txt ] [ -Aasymm_max ] [ -E ] [
-FacdhiInNtTvwxyz ] [ -I[list] ] [
-L[corrtable] ] [ -Nnx_min ] [
-Qe|i ] [ -Rregion ] [
-Strack ] [ -V[level] ] [ -W[list]
] [ -bobinary ]
Note: No space is allowed between the option flag and the
associated arguments.
x2sys_list will read the crossover ASCII data base
coedbase.txt (or stdin) and extract a subset of the crossovers
based on the other arguments. The output may be ASCII or binary.
- -Ccolumn
- Specify which data column you want to process. Crossovers related to this
column name must be present in the crossover data base.
- -TTAG
- Specify the x2sys TAG which tracks the attributes of this data
type.
- coedbase.txt
- The name of the input ASCII crossover error data base as produced by
x2sys_cross. If not given we read standard input instead.
- -Aasymm_max
- Specifies maximum asymmetry in the distribution of crossovers relative to
the mid point in time (or distance, if not time is available). Asymmetry
is computed as (n_right - n_left)/(n_right + n_left), referring the the
number of crossovers that falls in the left or right half of the range.
Symmetric distributions will have values close to zero. If specified, we
exclude tracks whose asymmetry exceeds the specify cutoff in absolute
value [1, i.e., include all].
- -E
- Enhance ASCII output by writing GMT segment headers with name of the two
tracks and their total number of cross-overs [no segment headers].
- -FacdhiInNtTvwxyz
- Specify your desired output using any combination of
acdhiInNtTvwxyz, in any order. Do not use space between the
letters, and note your selection is case-sensitive. The output will be
ASCII (or binary, -bo) columns of values. Description of codes:
a is the angle (< 90) defined by the crossing tracks, c
is crossover value of chosen observation (see -C), d is
distance along track, h is heading along track, i is the
signed time interval between the visit at the crossover of the two tracks
involved, I is same as i but is unsigned, n is the
names of the two tracks, N is the id numbers of the two tracks,
t is time along track in dateTclock format
(NaN if not available), T is elapsed time since start of track
along track (NaN if not available), v is speed along track,
w is the composite weight, x is x-coordinate (or
longitude), y is y-coordinate (or latitude), and z is
observed value (see -C) along track. If -S is not specified
then d,h,n,N,t,T,v
results in two output columns each: first for track one and next for track
two (in lexical order of track names); otherwise, they refer to the
specified track only (except for n,N which then refers to
the other track). The sign convention for c,i is track one
minus track two (lexically sorted). Time intervals will be returned
according to the TIME_UNIT GMT defaults setting.
- -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 the chosen observable. 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 x2sys_solve.
- -Nnx_min
- Only report data from pairs that generated at least nx_min
crossovers between them [use all pairs].
- -Qe|i
- Append e for external crossovers or i for internal
crossovers only [Default is all crossovers].
- -Rwest/east/south/north[/zmin/zmax][+r][+uunit]
- 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. Appending +uunit 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 bases the statistics on those COE that fall inside the specified
domain.
- -Strack
- Name of a single track. If given we restrict output to those crossovers
involving this track [Default output is crossovers involving any track
pair].
- -W[list]
- Name of ASCII file with a list of track names and their relative weights
(one track per record) that should be used to calculate the composite
crossover weight (output code w above). [Default sets weights to
1].
- -^ or just -
- Print a short message about the syntax of the command, then exits (NOTE:
on Windows just use -).
- -+ 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 all
options, then exits.
To find all the magnetic crossovers associated with the tag MGD77
from the file COE_data.txt, restricted to occupy a certain region in the
south Pacific, and return location, time, and crossover value, try
gmt x2sys_list COE_data.txt -V -TMGD77 -R180/240/-60/-30 -Cmag -Fxytz > mag_coe.txt
To find all the faa crossovers globally that involves track
12345678 and output time since start of the year, using a binary double
precision format, try
gmt x2sys_list COE_data.txt -V -TMGD77 -Cfaa -S12345678 -FTz -bod > faa_coe.b
x2sys_binlist, x2sys_cross, x2sys_datalist, x2sys_get, x2sys_init,
x2sys_put, x2sys_report, x2sys_solve
2019, P. Wessel, W. H. F. Smith, R. Scharroo, J. Luis, and F.
Wobbe