This is the command mgd77trackgmt that can be run in the OnWorks free hosting provider using one of our multiple free online workstations such as Ubuntu Online, Fedora Online, Windows online emulator or MAC OS online emulator
mgd77track - Plot track-line map of MGD77 cruises
mgd77track NGDC-ids region parameters [ [c][size][,spacing] ] [ [p|s]parameters ] [ f|g|e
] [ -Dastartdate ] [ bstopdate ] [ ] [ d|t|ngap ] [ ignore ] [ ] [ trackticks ] [
-o<flags> ] [ -p<flags> ] [ astartdist[u] ] [ bstopdist[u] ] [ T|t|dms,mc,mfs,mf,mfc ] [
[just/dx/dy/][c|label] ] [ [level] ] [ [-|+][pen] ] [ x_offset ] [ y_offset ] [ -ccopies ]
[ -p<flags> ] [ -t<transp> ]
Note: No space is allowed between the option flag and the associated arguments.
mgd77track reads NGDC MGD77 cruises and creates PostScript code that will plot one or more
ship tracks on a map using the specified projection. The PostScript code is written to
Can be one or more of five kinds of specifiers:
1. 8-character NGDC IDs, e.g., 01010083, JA010010etc., etc.
2. 2-character <agency> codes which will return all cruises from each agency.
3. 4-character <agency><vessel> codes, which will return all cruises from those
4. =<list>, where <list> is a table with NGDC IDs, one per line.
5. If nothing is specified we return all cruises in the data base.
(See mgd77info -L for agency and vessel codes). The ".mgd77" or ".nc" extensions
will automatically be appended, if needed (use -I to ignore certain file types).
Cruise files will be looked for first in the current directory and second in all
directories listed in $MGD77_HOME/mgd77_paths.txt [If $MGD77_HOME is not set it
will default to $GMT_SHAREDIR/mgd77].
-Jparameters (more ...)
Select map projection.
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.
Using -Runit 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
Append c to annotate using the MGD77 cruise ID [Default uses the filename prefix].
Optional size is the font size in points. The leg annotation font is controlled by
FONT_LABEL. By default, each leg is annotated every time it enters the map region.
Alternatively, append ,spacing to place this label every spacing units apart along
the track. Append one of the units k (km), n (nautical mile), d (day), or h (hour).
-B[p|s]parameters (more ...)
Set map boundary intervals.
Select procedure for along-track distance calculation:
f Flat Earth distances. g Great circle distances [Default]. e Geodesic
distances on current GMT ellipsoid.
Do not plot data collected before startdate (yyyy-mm-ddT[hh:mm:ss]) [Default is
Do not plot data collected after stopdate (yyyy-mm-ddT[hh:mm:ss]). [Default is last
-F Do not apply the error bit flags if present in a MGD77+ file [Default will apply
these flags upon reading the data].
Let successive point separations exceeding dgap (km) or tgap (minutes) indicate a
break in the track where we should not draw a line [no gaps recognized]. Repeat to
use both types of gap checking. The nN form is used to plot only one every other N
points. This is useful to reduce plot file size bat cannot be used (will be
ignored) with the other two gap types.
Ignore certain data file formats from consideration. Append a|c|t to ignore MGD77
ASCII, MGD77+ netCDF, or plain table files, respectively. The option may be
repeated to ignore more than one format. [Default ignores none].
-K (more ...)
Do not finalize the PostScript plot.
To put time/distance log-marks on the track. E.g. a500ka24ht6h means (a)nnotate
every 500 km (k) and 24 h(ours), with (t)ickmarks every 500 km and 6 hours.
Alternatively you may use the modifiers d (days) and n (nautical miles).
-O (more ...)
Append to existing PostScript plot.
-P (more ...)
Select "Portrait" plot orientation.
Do not plot data that are less than startdist meter along track from port of
departure. Append k for km, m for miles, or n for nautical miles [Default is 0
Do not plot data that are more than stopdist meter along track from port of
departure. Append k for km, m for miles, or n for nautical miles [Default is end of
Controls the attributes of the three kinds of markers (T for the first time marker
in a new day, t for additional time markers in the same day, and d for distance
markers). For each of these you can specify the 5 comma-separated attributes
markersize, markercolor, markerfontsize, markerfont, and markerfontcolor. Repeat
the -T option for each marker type.
-U[just/dx/dy/][c|label] (more ...)
Draw GMT time stamp logo on plot.
Append pen used for the trackline. [Defaults: width = default, color = black, style
= solid]. A leading + will use the lookup color (via -C) for both symbol fill and
outline pen color, while a leading - will set outline pen color and turn off symbol
-Y[a|c|f|r][y-shift[u]] (more ...)
Shift plot origin.
-V[level] (more ...)
Select verbosity level [c].
-ccopies (more ...)
Specify number of plot copies [Default is 1].
-p[x|y|z]azim/elev[/zlevel][+wlon0/lat0[/z0]][+vx0/y0] (more ...)
Select perspective view.
-t[transp] (more ...)
Set PDF transparency level in percent.
-^ or just -
Print a short message about the syntax of the command, then exits (NOTE: on Windows
use just -).
-+ 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 options, then
Print GMT version and exit.
Print full path to GMT share directory and exit.
To generate a Mercator plot of the track of the cruise 01010007 in the area 70W to 20E,
40S to 20N, using a Mercator scale of 0.1inch/degree, label the tracks with 10 points
characters, annotate the boundaries every 10 degrees, draw gridlines every 5 degrees, and
mark the track every day and 1000 km, with ticks every 6 hours and 250 km, and send the
plot to the default printer, enter the following command:
gmt mgd77track 01010007 -R70W/20E/40S/20N -Jm0.1 -B10g5 -A10 \
-La1da1000kf6hf250k \| lpr
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