man mgd77track () - A shiptrack plotting program


mgd77track - A shiptrack plotting program


mgd77track leg-ids -Rwest/east/south/north -Jparameters [ -A[c][size] ] [ -Btickinfo ] [ -Dastartdate ] [ -Dbstopdate ] [ -K ] [ -Mtrackticks ] [ -O ] [ -P ] [ -Sastartdist ] [ -Sbstopdist ] [ -TT|t|dms,mc,mfs,mf,mfc ] [ -U[dx/dy/][label] ] [ -V ] [ -Wpen ] [ -Xx-shift ] [ -Yy-shift ] [ -ccopies ]


mgd77track reads NGDC MGD-77 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 standard output.

Can be one or more NGDC names, like 01010007 etc.
Selects the map projection. Scale is UNIT/degree, 1:xxxxx, or width in UNIT (upper case modifier). UNIT is cm, inch, or m, depending on the MEASURE_UNIT setting in .gmtdefaults4, but this can be overridden on the command line by appending c, i, or m to the scale/width value. For map height, max dimension, or min dimension, append h, +, or - to the width, respectively.


-Jclon0/lat0/scale (Cassini)

-Jjlon0/scale (Miller)

-Jmscale (Mercator - Greenwich and Equator as origin)

-Jmlon0/lat0/scale (Mercator - Give meridian and standard parallel)

-Joalon0/lat0/azimuth/scale (Oblique Mercator - point and azimuth)

-Joblon0/lat0/lon1/lat1/scale (Oblique Mercator - two points)

-Joclon0/lat0/lonp/latp/scale (Oblique Mercator - point and pole)

-Jqlon0/scale (Equidistant Cylindrical Projection (Plate Carree))

-Jtlon0/scale (TM - Transverse Mercator, with Equator as y = 0)

-Jtlon0/lat0/scale (TM - Transverse Mercator, set origin)

-Juzone/scale (UTM - Universal Transverse Mercator)

-Jylon0/lats/scale (Basic Cylindrical Projection)


-Jalon0/lat0/scale (Lambert).

-Jelon0/lat0/scale (Equidistant).

-Jflon0/lat0/horizon/scale (Gnomonic).

-Jglon0/lat0/scale (Orthographic).

-Jslon0/lat0/[slat/]scale (General Stereographic)


-Jblon0/lat0/lat1/lat2/scale (Albers)

-Jdlon0/lat0/lat1/lat2/scale (Equidistant)

-Jllon0/lat0/lat1/lat2/scale (Lambert)


-Jhlon0/scale (Hammer)

-Jilon0/scale (Sinusoidal)

-Jk[f|s]lon0/scale (Eckert IV (f) and VI (s))

-Jnlon0/scale (Robinson)

-Jrlon0/scale (Winkel Tripel)

-Jvlon0/scale (Van der Grinten)

-Jwlon0/scale (Mollweide)


-Jp[a]scale[/origin] (polar (theta,r) coordinates, optional a for azimuths and offset theta [0])

-Jxx-scale[l|ppow][/y-scale[l|ppow]][d] (Linear, log, and power scaling)

More details can be found in the psbasemap man pages.

xmin, xmax, ymin, and ymax specify the Region of interest. For geographic regions, these limits correspond to west, east, south, and north and you may specify them in decimal degrees or in [+-]dd:mm[][W|E|S|N] format. Append r if lower left and upper right map coordinates are given instead of wesn. The two shorthands -Rg -Rd stand for global domain (0/360 or -180/+180 in longitude respectively, with -90/+90 in latitude). For calendar time coordinates you may either give relative time (relative to the selected TIME_EPOCH and in the selected TIME_UNIT; append t to -JX|x), or absolute time of the form [date]T[clock] (append T to -JX|x). At least one of date and clock must be present; the T is always required. The date string must be of the form [-]yyyy[-mm[-dd]] (Gregorian calendar) or yyyy[-Www[-d]] (ISO week calendar), while the clock string must be of the form hh:mm:ss[.xxx]. The use of delimiters and their type and positions must be as indicated (however, input/output and plotting formats are flexible).


No space between the option flag and the associated arguments.

Annotate each leg every time it enters the plot. 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 LABEL_FONT.
Sets map boundary annotation and tickmark intervals; see the psbasemap man page for all the details.
Do not plot data collected before startdate (yyyy-mm-ddT[hh:mm:ss]) [Default is first day].
Do not plot data collected after stopdate (yyyy-mm-ddT[hh:mm:ss]). [Default is last day].
More PostScript code will be appended later [Default terminates the plot system].
To put time/distance 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).
Selects Overlay plot mode [Default initializes a new plot system].
Selects Portrait plotting mode [GMT Default is Landscape, see gmtdefaults to change this].
Do not plot data that are less than startdist km along track from port of departure. Append k for km, m for miles, or n for nautical miles [Default is 0 meters].
Do not plot data that are more than stopdist km along track from port of departure. Append k for km, m for miles, or n for nautical miles [Default is length of track].
Controlls 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 markerconfcolor. Repeat the -T option for each marker type.
Draw Unix System time stamp on plot. User may specify where the lower left corner of the stamp should fall on the page relative to lower left corner of plot. Optionally, append a label, or c (which will plot the command string.). The GMT parameters UNIX_TIME and UNIX_TIME_POS can affect the appearance; see the gmtdefaults man page for details.
pen is the pne used for the trackline. [Default is 0.25p,black]. [Default is solid].
-X -Y
Shift origin of plot by (x-shift,y-shift). Prepend a for absolute coordinates; the default (r) will reset plot origin. Give c to center plot using current page size.
Selects verbose mode, which will send progress reports to stderr [Default runs "silently"].
Specifies the number of plot copies. [Default is 1].


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:

mgd77track 01010007 -R70W/20E/40S/20N -Jm0.1 -B10g5 -A10 -Ma1da1000kf6hf250k | lpr



Wessel, P., and W. H. F. Smith, 2004, The Generic Mapping Tools (GMT) version 4 Technical Reference & Cookbook, SOEST/NOAA.

Wessel, P., and W. H. F. Smith, 1998, New, Improved Version of Generic Mapping Tools Released, EOS Trans., AGU, 79 (47), p. 579.

Wessel, P., and W. H. F. Smith, 1995, New Version of the Generic Mapping Tools Released, EOS Trans., AGU, 76 (33), p. 329.

Wessel, P., and W. H. F. Smith, 1995, New Version of the Generic Mapping Tools Released, http: American Geophysical Union.

Wessel, P., and W. H. F. Smith, 1991, Free Software Helps Map and Display Data, EOS Trans., AGU, 72 (41), p. 441.