1GMT(1) GMT GMT(1)
2
6 gmt - The Generic Mapping Tools data processing and display software
7 package
8
10 GMT is a collection of public-domain Unix tools that allows you to
11 manipulate x,y and x,y,z data sets (filtering, trend fitting, gridding,
12 projecting, etc.) and produce PostScript illustrations ranging from
13 simple x-y plots, via contour maps, to artificially illuminated sur‐
14 faces and 3-D perspective views in black/white or full color. Linear,
15 log10, and power scaling is supported in addition to over 30 common map
16 projections. The processing and display routines within GMT are com‐
17 pletely general and will handle any (x,y) or (x,y,z) data as input.
18
20 gmt is the main program that can start any of the modules:
21 gmt module module-options
23 where module is the name of a GMT module and the options are those that
25 pertain to that particular module. A few special modules are also
26 available:
27 gmt clear items
29 while delete the user's history. Choose between history (deletes the
31 gmt.history file in the current directory), conf (deletes the gmt.conf
32 file in the current directory), cache (deletes the user's cache direc‐
33 tory and all of its content), or all (does all of the above).
34 If no module is given then several other options are available:
36 --help List and description of GMT modules.
38 --show-cores
40 Show number of available cores.
41 --show-bindir
43 Show directory of executables and exit.
44 --show-datadir
46 Show data directory/ies and exit.
47 --show-modules
49 List module names on stdout and exit.
50 --show-plugindir
52 Show plugin directory and exit.
53 --show-sharedir
55 Show share directory and exit.
56 --version
58 Print version and exit.
59 = Check if that module exist and if so the program will exit with
61 status of 0; otherwise the status of exit will be non-zero.
62
64 GMT provides basic command-line completion (tab completion) for bash.
65 The completion rules are either installed in /etc/bash_completion.d/gmt
66 or <prefix>/share/tools/gmt_completion.bash. Depending on the distri‐
67 bution, you may still need to source the gmt completion file from
68 ~/.bash_completion or ~/.bashrc. For more information see Section com‐
69 mand-line-completion in the CookBook.
70
72 The following is a summary of all the programs supplied with GMT and a
73 very short description of their purpose. Detailed information about
74 each program can be found in the separate manual pages.
75 ┌───────────────┬───────────────────────┐
77 │blockmean │ │
78 ├───────────────┼───────────────────────┤
79 │blockmedian │ │
80 ├───────────────┼───────────────────────┤
81 │blockmode │ │
82 ├───────────────┼───────────────────────┤
83 │filter1d │ │
84 ├───────────────┼───────────────────────┤
85 │fitcircle │ │
86 ├───────────────┼───────────────────────┤
87 │gmt2kml │ │
88 ├───────────────┼───────────────────────┤
89 │gmtconnect │ │
90 ├───────────────┼───────────────────────┤
91 │gmtconvert │ │
92 ├───────────────┼───────────────────────┤
93 │gmtdefaults │ │
94 ├───────────────┼───────────────────────┤
95 │gmtget │ │
96 ├───────────────┼───────────────────────┤
97 │gmtinfo │ │
98 ├───────────────┼───────────────────────┤
99 │gmtmath │ │
100 ├───────────────┼───────────────────────┤
101 │gmtselect │ │
102 ├───────────────┼───────────────────────┤
103 │gmtset │ │
104 ├───────────────┼───────────────────────┤
105 │gmtspatial │ │
106 ├───────────────┼───────────────────────┤
107 │gmtsimplify │ │
108 ├───────────────┼───────────────────────┤
109 │gmtvector │ │
110 ├───────────────┼───────────────────────┤
111 │gmtwhich │ │
112 ├───────────────┼───────────────────────┤
113 │grd2cpt │ │
114 ├───────────────┼───────────────────────┤
115 │grd2rgb │ │
116 ├───────────────┼───────────────────────┤
117 │grd2xyz │ │
118 ├───────────────┼───────────────────────┤
119 │grdblend │ │
120 ├───────────────┼───────────────────────┤
121 │grdclip │ │
122 ├───────────────┼───────────────────────┤
123 │grdcontour │ │
124 ├───────────────┼───────────────────────┤
125 │grdconvert │ │
126 ├───────────────┼───────────────────────┤
127 │grdcut │ │
128 ├───────────────┼───────────────────────┤
129 │grdedit │ │
130 └───────────────┴───────────────────────┘
131 │grdfft │ │
134 ├───────────────┼───────────────────────┤
135 │grdfilter │ │
136 ├───────────────┼───────────────────────┤
137 │grdgradient │ │
138 ├───────────────┼───────────────────────┤
139 │grdhisteq │ │
140 ├───────────────┼───────────────────────┤
141 │grdimage │ │
142 ├───────────────┼───────────────────────┤
143 │grdinfo │ │
144 ├───────────────┼───────────────────────┤
145 │grdlandmask │ │
146 ├───────────────┼───────────────────────┤
147 │grdmask │ │
148 ├───────────────┼───────────────────────┤
149 │grdmath │ │
150 ├───────────────┼───────────────────────┤
151 │grdpaste │ │
152 ├───────────────┼───────────────────────┤
153 │grdproject │ │
154 ├───────────────┼───────────────────────┤
155 │grdraster │ │
156 ├───────────────┼───────────────────────┤
157 │grdsample │ │
158 ├───────────────┼───────────────────────┤
159 │grdtrack │ │
160 ├───────────────┼───────────────────────┤
161 │grdtrend │ │
162 ├───────────────┼───────────────────────┤
163 │grdvector │ │
164 ├───────────────┼───────────────────────┤
165 │grdview │ │
166 ├───────────────┼───────────────────────┤
167 │grdvolume │ │
168 ├───────────────┼───────────────────────┤
169 │greenspline │ │
170 ├───────────────┼───────────────────────┤
171 │kml2gmt │ │
172 ├───────────────┼───────────────────────┤
173 │makecpt │ │
174 ├───────────────┼───────────────────────┤
175 │mapproject │ │
176 ├───────────────┼───────────────────────┤
177 │nearneighbor │ │
178 ├───────────────┼───────────────────────┤
179 │project │ │
180 ├───────────────┼───────────────────────┤
181 │psbasemap │ │
182 ├───────────────┼───────────────────────┤
183 │psclip │ │
184 ├───────────────┼───────────────────────┤
185 │pscoast │ │
186 ├───────────────┼───────────────────────┤
187 │pscontour │ │
188 ├───────────────┼───────────────────────┤
189 │psconvert │ │
190 ├───────────────┼───────────────────────┤
191 │pshistogram │ │
192 ├───────────────┼───────────────────────┤
193 │psimage │ │
194 ├───────────────┼───────────────────────┤
195 │pslegend │ │
196 └───────────────┴───────────────────────┘
197 │psmask │ │
200 ├───────────────┼───────────────────────┤
201 │psrose │ │
202 ├───────────────┼───────────────────────┤
203 │psscale │ │
204 ├───────────────┼───────────────────────┤
205 │pstext │ │
206 ├───────────────┼───────────────────────┤
207 │pswiggle │ │
208 ├───────────────┼───────────────────────┤
209 │psxy │ │
210 ├───────────────┼───────────────────────┤
211 │psxyz │ │
212 ├───────────────┼───────────────────────┤
213 │sample1d │ │
214 ├───────────────┼───────────────────────┤
215 │spectrum1d │ │
216 ├───────────────┼───────────────────────┤
217 │splitxyz │ │
218 ├───────────────┼───────────────────────┤
219 │surface │ │
220 ├───────────────┼───────────────────────┤
221 │trend1d │ │
222 ├───────────────┼───────────────────────┤
223 │trend2d │ │
224 ├───────────────┼───────────────────────┤
225 │triangulate │ │
226 ├───────────────┼───────────────────────┤
227 │xyz2grd │ │
228 ├───────────────┼───────────────────────┤
229 │ │ Supplement gshhg: │
230 ├───────────────┼───────────────────────┤
231 │gshhg │ │
232 ├───────────────┼───────────────────────┤
233 │ │ Supplement img: │
234 ├───────────────┼───────────────────────┤
235 │img2grd │ │
236 ├───────────────┼───────────────────────┤
237 │ │ Supplement meca: │
238 ├───────────────┼───────────────────────┤
239 │pscoupe │ │
240 ├───────────────┼───────────────────────┤
241 │psmeca │ │
242 ├───────────────┼───────────────────────┤
243 │pspolar │ │
244 ├───────────────┼───────────────────────┤
245 │psvelo │ │
246 ├───────────────┼───────────────────────┤
247 │pssac │ │
248 ├───────────────┼───────────────────────┤
249 │ │ Supplement mgd77: │
250 ├───────────────┼───────────────────────┤
251 │mgd77convert │ │
252 ├───────────────┼───────────────────────┤
253 │mgd77header │ │
254 ├───────────────┼───────────────────────┤
255 │mgd77info │ │
256 ├───────────────┼───────────────────────┤
257 │mgd77list │ │
258 ├───────────────┼───────────────────────┤
259 │mgd77magref │ │
260 ├───────────────┼───────────────────────┤
261 │mgd77manage │ │
262 └───────────────┴───────────────────────┘
263 │mgd77path │ │
266 ├───────────────┼───────────────────────┤
267 │mgd77sniffer │ │
268 ├───────────────┼───────────────────────┤
269 │mgd77track │ │
270 ├───────────────┼───────────────────────┤
271 │ │ Supplement potential: │
272 ├───────────────┼───────────────────────┤
273 │gmtgravmag3d │ │
274 ├───────────────┼───────────────────────┤
275 │gmtflexure │ │
276 ├───────────────┼───────────────────────┤
277 │gpsgridder │ │
278 ├───────────────┼───────────────────────┤
279 │gravfft │ │
280 ├───────────────┼───────────────────────┤
281 │grdflexure │ │
282 ├───────────────┼───────────────────────┤
283 │grdgravmag3d │ │
284 ├───────────────┼───────────────────────┤
285 │grdredpol │ │
286 ├───────────────┼───────────────────────┤
287 │grdseamount │ │
288 ├───────────────┼───────────────────────┤
289 │talwani2d │ │
290 ├───────────────┼───────────────────────┤
291 │talwani3d │ │
292 ├───────────────┼───────────────────────┤
293 │ │ Supplement segy: │
294 ├───────────────┼───────────────────────┤
295 │pssegy │ │
296 ├───────────────┼───────────────────────┤
297 │pssegyz │ │
298 ├───────────────┼───────────────────────┤
299 │segy2grd │ │
300 ├───────────────┼───────────────────────┤
301 │ │ Supplement sph: │
302 ├───────────────┼───────────────────────┤
303 │sphdistance │ │
304 ├───────────────┼───────────────────────┤
305 │sphinterpolate │ │
306 ├───────────────┼───────────────────────┤
307 │sphtriangulate │ │
308 ├───────────────┼───────────────────────┤
309 │ │ Supplement spotter: │
310 ├───────────────┼───────────────────────┤
311 │backtracker │ │
312 ├───────────────┼───────────────────────┤
313 │gmtpmodeler │ │
314 ├───────────────┼───────────────────────┤
315 │grdpmodeler │ │
316 ├───────────────┼───────────────────────┤
317 │grdrotater │ │
318 ├───────────────┼───────────────────────┤
319 │grdspotter │ │
320 ├───────────────┼───────────────────────┤
321 │hotspotter │ │
322 ├───────────────┼───────────────────────┤
323 │originator │ │
324 ├───────────────┼───────────────────────┤
325 │rotconverter │ │
326 ├───────────────┼───────────────────────┤
327 │rotsmoother │ │
328 └───────────────┴───────────────────────┘
329 │ │ Supplement x2sys: │
332 ├───────────────┼───────────────────────┤
333 │x2sys_binlist │ │
334 ├───────────────┼───────────────────────┤
335 │x2sys_cross │ │
336 ├───────────────┼───────────────────────┤
337 │x2sys_datalist │ │
338 ├───────────────┼───────────────────────┤
339 │x2sys_get │ │
340 ├───────────────┼───────────────────────┤
341 │x2sys_init │ │
342 ├───────────────┼───────────────────────┤
343 │x2sys_list │ │
344 ├───────────────┼───────────────────────┤
345 │x2sys_merge │ │
346 ├───────────────┼───────────────────────┤
347 │x2sys_put │ │
348 ├───────────────┼───────────────────────┤
349 │x2sys_report │ │
350 ├───────────────┼───────────────────────┤
351 │x2sys_solve │ │
352 └───────────────┴───────────────────────┘
353
355 The gmt program can also load custom modules from shared libraries
356 built as specified in the GMT API documentation. This way your modules
357 can benefit form the GMT infrastructure and extend GMT in specific
358 ways.
359
361 -B[p|s]parameters -Jparameters -Jz|Zparameters -K -O -P
362 -Rwest/east/south/north[/zmin/zmax][+r]
363 -U[stamp]
364 -V[level]
365 -Xx_offset
366 -Yy_offset -aflags -bbinary -dnodata -fflags -ggaps -hheaders -iflags
367 -nflags -oflags -pflags -r -sflags -ttransp -x[[-]n] -:[i|o]
368
370 These are all the common GMT options that remain the same for all GMT
371 programs. No space between the option flag and the associated argu‐
372 ments.
373 -B[p|s]parameters
375 Set map Frame and Axes parameters. The Frame parameters are
376 specified by
377 -B[axes][+b][+gfill][+n][+olon/lat][+ttitle]
379 where axes selects which axes to plot. By default, all 4 map
381 boundaries (or plot axes) are plotted (named W, E, S, N). To
382 customize, append the codes for those you want (e.g., WSn).
383 Upper case means plot and annotate while lower case just plots
384 the specified axes. If a 3-D basemap is selected with -p and
385 -Jz, append Z or z to control the appearance of the vertical
386 axis. By default a single vertical axes will be plotted at the
387 most suitable map corner. Override the default by appending any
388 combination of corner ids 1234, where 1 represents the lower
389 left corner and the order goes counter-clockwise. Append +b to
390 draw the outline of the 3-D cube defined by -R; this modifier is
391 also needed to display gridlines in the x-z, y-z planes. Note
392 that for 3-D views the title, if given, will be suppressed. You
393 can paint the interior of the canvas with +gfill. Append +n to
394 have no frame and annotations at all [Default is controlled by
395 the codes]. Optionally append +oplon/plat to draw oblique grid‐
396 lines about specified pole [regular gridlines]. Ignored if grid‐
397 lines are not requested (below) and disallowed for the oblique
398 Mercator projection. To add a plot title (+ttitle). The Frame
399 setting is optional but can be invoked once to override the
400 above defaults.
401 The Axes parameters are specified by
403 -B[p|s][x|y|z]intervals[+l|Llabel][+pprefix][+uunit]
405 but you may also split this into two separate invocations for
407 clarity, i.e.,
408 · -B[p|s][x|y|z][+l|Llabel][+pprefix][+uunit]
410 · -B[p|s][x|y|z]intervals
412 The first optional flag following -B selects p (rimary) [Default] or
414 s (econdary) axes information (mostly used for time axes annota‐
415 tions). The [x|y|z] flags specify which axes you are providing
416 information for. If none are given then we default to xy. If you
417 wish to give different annotation intervals or labels for the various
418 axes then you must repeat the B option for each axis (If a 3-D
419 basemap is selected with -p and -Jz, use -Bz to give settings for the
420 vertical axis.). To add a label to an axis, just append +llabel
421 (Cartesian projections only). Use +L to force a horizontal label for
422 y-axes (useful for very short labels). If the axis annotation should
423 have a leading text prefix (e.g., dollar sign for those plots of your
424 net worth) you can append +pprefix. For geographic maps the addition
425 of degree symbols, etc. is automatic (and controlled by the GMT
426 default setting FORMAT_GEO_MAP). However, for other plots you can add
427 specific units by adding +uunit. If any of these text strings con‐
428 tain spaces or special characters you will need to enclose them in
429 quotes. The intervals specification is a concatenated string made up
430 of substrings of the form
431 [a|f|g]stride[+-phase][u].
433 The leading a is used to specify the annotation and major tick spac‐
435 ing [Default], f for minor tick spacing, and g for gridline spacing.
436 stride is the desired stride interval. The optional phase shifts the
437 annotation interval by that amount (positive or negative). The
438 optional unit indicates the unit of the stride and can be any of
439 · Y (year, plot with 4 digits)
441 · y (year, plot with 2 digits)
443 · O (month, plot using FORMAT_DATE_MAP)
445 · o (month, plot with 2 digits)
447 · U (ISO week, plot using FORMAT_DATE_MAP)
449 · u (ISO week, plot using 2 digits)
451 · r (Gregorian week, 7-day stride from start of week TIME_WEEK_START)
453 · K (ISO weekday, plot name of day)
455 · D (date, plot using FORMAT_DATE_MAP)
457 · d (day, plot day of month 0-31 or year 1-366, via FORMAT_DATE_MAP)
459 · R (day, same as d, aligned with TIME_WEEK_START)
461 · H (hour, plot using FORMAT_CLOCK_MAP)
463 · h (hour, plot with 2 digits)
465 · M (minute, plot using FORMAT_CLOCK_MAP)
467 · m (minute, plot with 2 digits)
469 · S (second, plot using FORMAT_CLOCK_MAP)
471 · s (second, plot with 2 digits).
473 Note for geographic axes m and s instead mean arc minutes and arc
475 seconds. All entities that are language-specific are under control
476 by GMT_LANGUAGE. Alternatively, for linear maps, we can omit stride,
477 thus setting xinfo, yinfo, or zinfo to a plots annotations at auto‐
478 matically determined intervals,
479 · ag plots both annotations and grid lines with the same spacing,
481 · afg adds suitable minor tick intervals,
483 · g plots grid lines with the same interval as if -Bf was used.
485 For custom annotations and intervals, let intervals be given as cint‐
487 file, where intfile contains any number of records with coord type
488 [label]. Here, type is one or more letters from a|i, f, and g. For
489 a|i you must supply a label that will be plotted at the coord loca‐
490 tion. For non-geographical projections: Give negative scale (in -Jx)
491 or axis length (in -JX) to change the direction of increasing coordi‐
492 nates (i.e., to make the y-axis positive down). For log10 axes:
493 Annotations can be specified in one of three ways:
494 1. stride can be 1, 2, 3, or -n. Annotations will then occur at 1,
496 1-2-5, or 1-2-3-4-...-9, respectively; for -n we annotate every
497 n't magnitude. This option can also be used for the frame and grid
498 intervals.
499 2. An l is appended to the tickinfo string. Then, log10 of the tick
501 value is plotted at every integer log10 value.
502 3. A p is appended to the tickinfo string. Then, annotations appear
504 as 10 raised to log10 of the tick value.
505 For power axes: Annotations can be specified in one of two ways:
507 1. stride sets the regular annotation interval.
509 2. A p is appended to the tickinfo string. Then, the annotation
511 interval is expected to be in transformed units, but the annota‐
512 tion value will be plotted as untransformed units. E.g., if stride
513 = 1 and power = 0.5 (i.e., sqrt), then equidistant annotations
514 labeled 1-4-9... will appear.
515 These GMT parameters can affect the appearance of the map boundary:
517 MAP_ANNOT_MIN_ANGLE, MAP_ANNOT_MIN_SPACING, FONT_ANNOT_PRIMARY,
518 FONT_ANNOT_SECONDARY, MAP_ANNOT_OFFSET_PRIMARY, MAP_ANNOT_OFFSET_SEC‐
519 ONDARY, MAP_ANNOT_ORTHO, MAP_FRAME_AXES, MAP_DEFAULT_PEN,
520 MAP_FRAME_TYPE, FORMAT_GEO_MAP, MAP_FRAME_PEN, MAP_FRAME_WIDTH,
521 MAP_GRID_CROSS_SIZE_PRIMARY, MAP_GRID_PEN_PRIMARY,
522 MAP_GRID_CROSS_SIZE_SECONDARY, MAP_GRID_PEN_SECONDARY, FONT_TITLE,
523 FONT_LABEL, MAP_LINE_STEP, MAP_ANNOT_OBLIQUE, FORMAT_CLOCK_MAP, FOR‐
524 MAT_DATE_MAP, FORMAT_TIME_PRIMARY_MAP, FORMAT_TIME_SECONDARY_MAP,
525 GMT_LANGUAGE, TIME_WEEK_START, MAP_TICK_LENGTH_PRIMARY, and
526 MAP_TICK_PEN_PRIMARY; see the gmt.conf man page for details.
527 -Jparameters
529 Select map projection. The following character determines the projec‐
531 tion. If the character is upper case then the argument(s) supplied as
532 scale(s) is interpreted to be the map width (or axis lengths), else the
533 scale argument(s) is the map scale (see its definition for each projec‐
534 tion). UNIT is cm, inch, or point, depending on the PROJ_LENGTH_UNIT
535 setting in gmt.conf, but this can be overridden on the command line by
536 appending c, i, or p to the scale or width values. Append h, +, or - to
537 the given width if you instead want to set map height, the maximum
538 dimension, or the minimum dimension, respectively [Default is w for
539 width]. In case the central meridian is an optional parameter and it
540 is being omitted, then the center of the longitude range given by the
541 -R option is used. The default standard parallel is the equator. The
542 ellipsoid used in the map projections is user-definable by editing the
543 gmt.conf file in your home directory. 73 commonly used ellipsoids and
544 spheroids are currently supported, and users may also specify their own
545 custom ellipsoid parameters [Default is WGS-84]. Several GMT parame‐
546 ters can affect the projection: PROJ_ELLIPSOID, GMT_INTERPOLANT,
547 PROJ_SCALE_FACTOR, and PROJ_LENGTH_UNIT; see the gmt.conf man page for
548 details. Choose one of the following projections (The E or C after
549 projection names stands for Equal-Area and Conformal, respectively):
550 CYLINDRICAL PROJECTIONS:
551 -Jclon0/lat0/scale or -JClon0/lat0/width (Cassini).
552 Give projection center lon0/lat0 and scale (1:xxxx or
553 UNIT/degree).
554 -Jcyl_stere/[lon0/[lat0/]]scale or -JCyl_stere/[lon0/[lat0/]]width
555 (Cylindrical Stereographic).
556 Give central meridian lon0 (optional), standard parallel lat0
557 (optional), and scale along parallel (1:xxxx or UNIT/degree).
558 The standard parallel is typically one of these (but can be any
559 value):
560 · 66.159467 - Miller's modified Gall
562 · 55 - Kamenetskiy's First
564 · 45 - Gall's Stereographic
566 · 30 - Bolshoi Sovietskii Atlas Mira or Kamenetskiy's Second
568 · 0 - Braun's Cylindrical
570 -Jj[lon0/]scale or -JJ[lon0/]width (Miller Cylindrical Projection).
571 Give the central meridian lon0 (optional) and scale (1:xxxx or
572 UNIT/degree).
573 -Jm[lon0/[lat0/]]scale or -JM[lon0/[lat0/]]width (Mercator [C])
574 Give central meridian lon0 (optional), standard parallel lat0
575 (optional), and scale along parallel (1:xxxx or UNIT/degree).
576 -Joparameters (Oblique Mercator [C]).
577 Typically used with -RLLx/LLy/URx/URyr or with projected coordi‐
578 nates. Specify one of:
579 -Jo[a|A]lon0/lat0/azimuth/scale or
581 -JO[a|A]lon0/lat0/azimuth/width
582 Set projection center lon0/lat0, azimuth of oblique equa‐
583 tor, and scale.
584 -Jo[b|B]lon0/lat0/lon1/lat1/scale or
586 -JO[b|B]lon0/lat0/lon1/lat1/scale
587 Set projection center lon0/lat0, another point on the
588 oblique equator lon1/lat1, and scale.
589 -Joc|Clon0/lat0/lonp/latp/scale or
591 -JOc|Clon0/lat0/lonp/latp/scale
592 Set projection center lon0/lat0, pole of oblique projec‐
593 tion lonp/latp, and scale. Give scale along oblique
594 equator (1:xxxx or UNIT/degree). The upper-case A|B|C to
595 removes enforcement of a northern hemisphere pole.
596 -Jq[lon0/[lat0/]]scale or -JQ[lon0/[lat0/]]width (Cylindrical
597 Equidistant).
598 Give the central meridian lon0 (optional), standard parallel
599 lat0 (optional), and scale (1:xxxx or UNIT/degree). The standard
600 parallel is typically one of these (but can be any value):
601 · 61.7 - Grafarend and Niermann, minimum linear distortion
603 · 50.5 - Ronald Miller Equirectangular
605 · 43.5 - Ronald Miller, minimum continental distortion
607 · 42 - Grafarend and Niermann
609 · 37.5 - Ronald Miller, minimum overall distortion
611 · 0 - Plate Carree, Simple Cylindrical, Plain/Plane Chart
613 -Jtlon0/[lat0/]scale or -JTlon0/[lat0/]width (Transverse Mercator
614 [C])
615 Give the central meridian lon0, central parallel lat0
616 (optional), and scale (1:xxxx or UNIT/degree).
617 -Juzone/scale or -JUzone/width (UTM - Universal Transverse Mercator
618 [C]).
619 Give the UTM zone (A,B,1-60[C-X],Y,Z)) and scale (1:xxxx or
620 UNIT/degree). Zones: If C-X not given, prepend - or + to
621 enforce southern or northern hemisphere conventions [northern if
622 south > 0].
623 -Jy[lon0/[lat0/]]scale or -JY[lon0/[lat0/]]width (Cylindrical
624 Equal-Area [E]).
625 Give the central meridian lon0 (optional), standard parallel
626 lat0 (optional), and scale (1:xxxx or UNIT/degree). The standard
627 parallel is typically one of these (but can be any value):
628 · 50 - Balthasart
630 · 45 - Gall
632 · 37.0666 - Caster
634 · 37.4 - Trystan Edwards
636 · 37.5 - Hobo-Dyer
638 · 30 - Behrman
640 · 0 - Lambert (default)
642 CONIC PROJECTIONS:
644 -Jblon0/lat0/lat1/lat2/scale or -JBlon0/lat0/lat1/lat2/width (Albers
646 [E]).
647 Give projection center lon0/lat0, two standard parallels
648 lat1/lat2, and scale (1:xxxx or UNIT/degree).
649 -Jdlon0/lat0/lat1/lat2/scale or -JDlon0/lat0/lat1/lat2/width (Conic
651 Equidistant)
652 Give projection center lon0/lat0, two standard parallels
653 lat1/lat2, and scale (1:xxxx or UNIT/degree).
654 -Jllon0/lat0/lat1/lat2/scale or -JLlon0/lat0/lat1/lat2/width (Lam‐
656 bert [C])
657 Give origin lon0/lat0, two standard parallels lat1/lat2, and
658 scale along these (1:xxxx or UNIT/degree).
659 -Jpoly/[lon0/[lat0/]]scale or -JPoly/[lon0/[lat0/]]width ((American)
661 Polyconic).
662 Give the central meridian lon0 (optional), reference parallel
663 lat0 (optional, default = equator), and scale along central
664 meridian (1:xxxx or UNIT/degree).
665 AZIMUTHAL PROJECTIONS:
667 Except for polar aspects, -Rw/e/s/n will be reset to -Rg. Use
669 -R<...>r for smaller regions.
670 -Jalon0/lat0[/horizon]/scale or -JAlon0/lat0[/horizon]/width (Lam‐
672 bert [E]).
673 lon0/lat0 specifies the projection center. horizon specifies
674 the max distance from projection center (in degrees, <= 180,
675 default 90). Give scale as 1:xxxx or radius/lat, where radius
676 is distance in UNIT from origin to the oblique latitude lat.
677 -Jelon0/lat0[/horizon]/scale or -JElon0/lat0[/horizon]/width
679 (Azimuthal Equidistant).
680 lon0/lat0 specifies the projection center. horizon specifies
681 the max distance from projection center (in degrees, <= 180,
682 default 180). Give scale as 1:xxxx or radius/lat, where
683 radius is distance in UNIT from origin to the oblique lati‐
684 tude lat.
685 -Jflon0/lat0[/horizon]/scale or -JFlon0/lat0[/horizon]/width
687 (Gnomonic).
688 lon0/lat0 specifies the projection center. horizon specifies
689 the max distance from projection center (in degrees, < 90,
690 default 60). Give scale as 1:xxxx or radius/lat, where radius
691 is distance in UNIT from origin to the oblique latitude lat.
692 -Jglon0/lat0[/horizon]/scale or -JGlon0/lat0[/horizon]/width (Ortho‐
694 graphic).
695 lon0/lat0 specifies the projection center. horizon specifies
696 the max distance from projection center (in degrees, <= 90,
697 default 90). Give scale as 1:xxxx or radius/lat, where radius
698 is distance in UNIT from origin to the oblique latitude lat.
699 -Jglon0/lat0/altitude/azimuth/tilt/twist/Width/Height/scale or
701 -JGlon0/lat0/altitude/azimuth/tilt/twist/Width/Height/width (General
702 Perspective).
703 lon0/lat0 specifies the projection center. altitude is the
704 height (in km) of the viewpoint above local sea level. If
705 altitude is less than 10, then it is the distance from the
706 center of the earth to the viewpoint in earth radii. If alti‐
707 tude has a suffix r then it is the radius from the center of
708 the earth in kilometers. azimuth is measured to the east of
709 north of view. tilt is the upward tilt of the plane of pro‐
710 jection. If tilt is negative, then the viewpoint is centered
711 on the horizon. Further, specify the clockwise twist, Width,
712 and Height of the viewpoint in degrees. Give scale as 1:xxxx
713 or radius/lat, where radius is distance in UNIT from origin
714 to the oblique latitude lat.
715 -Jslon0/lat0[/horizon]/scale or -JSlon0/lat0[/horizon]/width (Gen‐
717 eral Stereographic [C]).
718 lon0/lat0 specifies the projection center. horizon specifies
719 the max distance from projection center (in degrees, < 180,
720 default 90). Give scale as 1:xxxx (true at pole) or
721 lat0/1:xxxx (true at standard parallel lat) or radius/lat
722 (radius in UNIT from origin to the oblique latitude lat).
723 Note if 1:xxxx is used then to specify horizon you must also
724 specify the lat as +-90 to avoid ambiguity.
725 MISCELLANEOUS PROJECTIONS:
727 -Jh[lon0/]scale or -JH[lon0/]width (Hammer [E]).
729 Give the central meridian lon0 (optional) and scale along
730 equator (1:xxxx or UNIT/degree).
731 -Ji[lon0/]scale or -JI[lon0/]width (Sinusoidal [E]).
733 Give the central meridian lon0 (optional) and scale along
734 equator (1:xxxx or UNIT/degree).
735 -Jkf[lon0/]scale or -JKf[lon0/]width (Eckert IV) [E]).
737 Give the central meridian lon0 (optional) and scale along
738 equator (1:xxxx or UNIT/degree).
739 -Jk[s][lon0/]scale or -JK[s][lon0/]width (Eckert VI) [E]).
741 Give the central meridian lon0 (optional) and scale along
742 equator (1:xxxx or UNIT/degree).
743 -Jn[lon0/]scale or -JN[lon0/]width (Robinson).
745 Give the central meridian lon0 (optional) and scale along
746 equator (1:xxxx or UNIT/degree).
747 -Jr[lon0/]scale -JR[lon0/]width (Winkel Tripel).
749 Give the central meridian lon0 (optional) and scale along
750 equator (1:xxxx or UNIT/degree).
751 -Jv[lon0/]scale or -JV[lon0/]width (Van der Grinten).
753 Give the central meridian lon0 (optional) and scale along
754 equator (1:xxxx or UNIT/degree).
755 -Jw[lon0/]scale or -JW[lon0/]width (Mollweide [E]).
757 Give the central meridian lon0 (optional) and scale along
758 equator (1:xxxx or UNIT/degree).
759 NON-GEOGRAPHICAL PROJECTIONS:
761 -Jp[a]scale[/origin][r|z] or -JP[a]width[/origin][r|z] (Polar coor‐
762 dinates (theta,r))
763 Optionally insert a after -Jp [ or -JP] for azimuths CW from North
765 instead of directions CCW from East [Default]. Optionally append
766 /origin in degrees to indicate an angular offset [0]). Finally,
767 append r if r is elevations in degrees (requires s >= 0 and n <= 90)
768 or z if you want to annotate depth rather than radius [Default].
769 Give scale in UNIT/r-unit.
770 -Jxx-scale[/y-scale] or -JXwidth[/height] (Linear, log, and power
771 scaling)
772 Give x-scale (1:xxxx or UNIT/x-unit) and/or y-scale (1:xxxx or
774 UNIT/y-unit); or specify width and/or height in UNIT.
775 y-scale=x-scale if not specified separately and using 1:xxxx implies
776 that x-unit and y-unit are in meters. Use negative scale(s) to
777 reverse the direction of an axis (e.g., to have y be positive down).
778 Set height or width to 0 to have it recomputed based on the implied
779 scale of the other axis. Optionally, append to x-scale, y-scale,
780 width or height one of the following:
781 d Data are geographical coordinates (in degrees).
783 l Take log10 of values before scaling.
785 ppower Raise values to power before scaling.
787 t Input coordinates are time relative to TIME_EPOCH.
789 T Input coordinates are absolute time.
791 For mixed axes with only one geographic axis you may need to set
793 -f as well. Default axis lengths (see gmt.conf) can be invoked
794 using -JXh (for landscape); -JXv (for portrait) will swap the x-
795 and y-axis lengths. The default unit for this installation is
796 either cm or inch, as defined in the file share/gmt.conf. How‐
797 ever, you may change this by editing your gmt.conf file(s).
798 When -J is used without any further arguments, or just with the projec‐
800 tion type, the arguments of the last used -J, or the last used -J with
801 that projection type, will be used.
802 -Jz|Zparameters
804 Set z-axis scaling; same syntax as -Jx.
805 -K More PostScript code will be appended later [Default terminates
807 the plot system]. Required for all but the last plot command
808 when building multi-layer plots.
809 -O Selects Overlay plot mode [Default initializes a new plot sys‐
811 tem]. Required for all but the first plot command when building
812 multi-layer plots.
813 -P Select "Portrait" plot orientation [Default is "Landscape"; see
815 gmt.conf or gmtset to change the PS_PAGE_ORIENTATION parameter,
816 or supply --PS_PAGE_ORIENTATION=orientation on the command
817 line].
818 -Rxmin/xmax/ymin/ymax[+r][+uunit]
820 xmin, xmax, ymin, and ymax specify the region of interest. For
821 geographic regions, these limits correspond to west, east,
822 south, and north and you may specify them in decimal degrees or
823 in [+|-]dd:mm[:ss.xxx][W|E|S|N] format. Append +r if lower left
824 and upper right map coordinates are given instead of
825 west/east/south/north. The two shorthands -Rg and -Rd stand for
826 global domain (0/360 and -180/+180 in longitude respectively,
827 with -90/+90 in latitude). Alternatively for grid creation,
828 give -Rcodex0/y0/nx/ny, where code is a 2-character combination
829 of L, C, R (for left, center, or right) and T, M, B for top,
830 middle, or bottom. e.g., BL for lower left. This indicates
831 which point on a rectangular region the x0/y0 coordinate refers
832 to, and the grid dimensions nx and ny with grid spacings via -I
833 is used to create the corresponding region. Alternatively,
834 specify the name of an existing grid file and the -R settings
835 (and grid spacing, if applicable) are copied from the grid. When
836 -R is used without any further arguments, the values from the
837 last use of -R in a previous GMT command will be used. For cal‐
838 endar time coordinates you may either give (a) relative time
839 (relative to the selected TIME_EPOCH and in the selected
840 TIME_UNIT; append t to -JX|x), or (b) absolute time of the form
841 [date]T[clock] (append T to -JX|x). At least one of date and
842 clock must be present; the T is always required. The date string
843 must be of the form [-]yyyy[-mm[-dd]] (Gregorian calendar) or
844 yyyy[-Www[-d]] (ISO week calendar), while the clock string must
845 be of the form hh:mm:ss[.xxx]. The use of delimiters and their
846 type and positions must be exactly as indicated (however, input,
847 output and plot formats are customizable; see gmt.conf). You
848 can also use Cartesian projected coordinates compatible with the
849 chosen projection. Append the length unit via the +u modifier,
850 (e.g., -R-200/200/-300/300+uk for a 400 by 600 km rectangular
851 area centered on the projection center (0, 0). These coordinates
852 are internally converted to the corresponding geographic (longi‐
853 tude, latitude) coordinates for the lower left and upper right
854 corners. This form is convenient when you want to specify a
855 region directly in the projected units (e.g., UTM meters).
856 In case of perspective view p, a z-range (zmin, zmax) can be appended
858 to indicate the third dimension. This needs to be done only when using
859 the Jz option, not when using only the p option. In the latter case a
860 perspective view of the plane is plotted, with no third dimension.
861 -U[[just]/dx/dy/][c|label]
863 Draw Unix System time stamp on plot. By adding [just]/dx/dy/,
864 the user may specify the justification of the stamp and where
865 the stamp should fall on the page relative to lower left corner
866 of the plot. For example, BL/0/0 will align the lower left cor‐
867 ner of the time stamp with the lower left corner of the plot
868 [LL]. Optionally, append a label, or c (which will plot the com‐
869 mand string.). The GMT parameters MAP_LOGO, MAP_LOGO_POS, and
870 FORMAT_TIME_STAMP can affect the appearance; see the gmt.conf
871 man page for details. The time string will be in the locale set
872 by the environment variable TZ (generally local time).
873 -V[level]
875 Select verbose mode, which will send progress reports to stderr.
876 Choose among 6 levels of verbosity; each level adds more mes‐
877 sages: q - Complete silence, not even fatal error messages are
878 produced. n - Normal verbosity: produce only fatal error mes‐
879 sages. c - Produce also compatibility warnings (same as when -V
880 is omitted). v - Produce also warnings and progress messages
881 (same as -V only). l - Produce also detailed progress messages.
882 d - Produce also debugging messages.
883 -X[a|c|f|r][x-shift[u]]
885 -Y[a|c|f|r][y-shift[u]]
887 Shift plot origin relative to the current origin by
888 (x-shift,y-shift) and optionally append the length unit (c, i,
889 or p). You can prepend a to shift the origin back to the origi‐
890 nal position after plotting, prepend c to center the plot on the
891 center of the paper (optionally add shift), prepend f to shift
892 the origin relative to the fixed lower left corner of the page,
893 or prepend r [Default] to move the origin relative to its cur‐
894 rent location. If -O is used then the default (x-shift,y-shift)
895 is (r0), otherwise it is (r1i). When -X or -Y are used without
896 any further arguments, the values from the last use of that
897 option in a previous GMT command will be used.
898 -a[col=]name[...]
900 Control how aspatial data are handled in GMT during input and
901 output. Reading OGR/GMT-formatted files: To assign certain
902 aspatial data items to GMT data columns, give one or more
903 comma-separated associations col=name, where name is the name of
904 an aspatial attribute field in a OGR/GMT file and whose value we
905 wish to use as data input for column col. In addition, to assign
906 an aspatial value to non-column data, you may specify col as D
907 for distance, G for fill, I for ID, L for label, T for text, W
908 for pen, and Z for value [e.g., used to look up color via a
909 CPT]. If you skip the leading "col=" in the argument then we
910 supply (and automatically increment) a column value starting at
911 2. Writing OGR/GMT-formatted files: To write OGR/GMT-formatted
912 files, give one or more comma-separated associations
913 col=name[:type], with an optional data type from DOUBLE, FLOAT,
914 INTEGER, CHAR, STRING, DATETIME, or LOGICAL [DOUBLE]. To extract
915 information from GMT multisegment headers encoded in the -Ddis‐
916 tance, -Gfill, -IID, -Llabel, -Ttext, -Wpen, or -Zvalue set‐
917 tings, specify COL as D, G, I, L, T, W or Z, respectively; type
918 will be set automatically. Finally, you must append +ggeometry,
919 where geometry is either POINT, LINE, or POLY. Optionally,
920 prepend M for multi-versions of these geometries. To force the
921 clipping of features crossing the Dateline, use upper-case +G
922 instead. See GMT Appendix Q for details of the OGR/GMT file for‐
923 mat.
924 -bi[ncols][type][w][+L|+B]
926 Select native binary input. Here, ncols is the number of data
927 columns of given type, which must be one of c (int8_t, aka
928 char), u (uint8_t, aka unsigned char), h (int16_t, 2-byte signed
929 int), H (uint16_t, 2-byte unsigned int), i (int32_t, 4-byte
930 signed int), I ((capital i) uint32_t, 4-byte unsigned int), l
931 ((lower case el) int64_t, 8-byte signed int), L (uint64_t,
932 8-byte unsigned int), f (4-byte single-precision float), and d
933 (8-byte double-precision float). In addition, use x to skip
934 ncols bytes anywhere in the record. For records with mixed
935 types, simply append additional comma-separated combinations of
936 ncolst. Append w to any item to force byte-swapping. Alterna‐
937 tively, append +L|B to indicate that the entire data file should
938 be read as little- or big-endian, respectively. The cumulative
939 number of ncols may exceed the columns actually needed by the
940 program. If ncols is not specified we assume that type applies
941 to all columns and that ncols is implied by the expectation of
942 the program. If the input file is netCDF, no -b is needed; sim‐
943 ply append ?var1/var2/... to the filename to specify the vari‐
944 ables to be read.
945 -bo[ncols][type][w][+L|+B]
947 Select native binary output. Here, ncols is the actual number of
948 data columns of type t, which must be one of c, u, h, H, i, I
949 (capital i), l (lower case elle), L, f, and d (see -bi). For a
950 mixed-type output record, append additional comma-separated com‐
951 binations of ncols/t. Append w to any item to force byte-swap‐
952 ping or +L|B for byte-swapping of the entire record. If ncols is
953 not specified we assume that t applies to all columns and that
954 ncols is implied by the default output of the program. Note:
955 NetCDF file output is not supported.
956 -d[i|o]nodata
958 Control how user-coded missing data values are translated to
959 official NaN values in GMT. For input data we replace any value
960 that equals nodata with NaN. For output data we replace any NaN
961 with the chosen nodata value. Use -di or -do to only affect
962 input or output.
963 -dinodata
965 Examine all input columns and if any item equals nodata we
966 interpret this value as a missing data item and substitute the
967 value NaN.
968 -donodata
970 Examine all output columns and if any item equals NAN we substi‐
971 tute it with the chosen missing data value nodata.
972 -e[~]"pattern" | -e[~]/regexp/[i]
974 Only accept ASCII data records that contains the specified pat‐
975 tern. To reverse the search, i.e., to only accept data record
976 that do not contain the specified pattern, use -e~. Should your
977 pattern happen to start with ~ you need to escape this character
978 with a backslash [Default accepts all data records]. For match‐
979 ing data records against extended regular expressions enclose
980 the expression in slashes. Append i for case-insensitive match‐
981 ing. For a list of such patterns, give +ffile with one pattern
982 per line. To give a single pattern starting with +f, escape it
983 with a backslash.
984 -f[i|o]colinfo
986 Specify the data types of input and/or output columns (time or
987 geographical data). Specify i or o to make this apply only to
988 input or output [Default applies to both]. Give one or more col‐
989 umns (or column ranges) separated by commas, or use -f multiple
990 times (column ranges must be given in the format start[:inc
991 ]:stop, where inc defaults to 1 if not specified). Append T
992 (absolute calendar time), t (relative time in chosen TIME_UNIT
993 since TIME_EPOCH), x (longitude), y (latitude), p[unit] (pro‐
994 jected x,y map coordinates in given unit [meter]) or f (floating
995 point) to each column or column range item. Shorthands -f[i|o]g
996 means -f[i|o]0x,1y (geographic coordinates) and -f[i|o]c means
997 -f[i|o]0-1f (Cartesian coordinates)
998 -g[a]x|y|d|X|Y|D|[col]z[+|-]gap[u]
1000 Examine the spacing between consecutive data points in order to
1001 impose breaks in the line. Append x|X or y|Y to define a gap
1002 when there is a large enough change in the x or y coordinates,
1003 respectively, or d|D for distance gaps; use upper case to calcu‐
1004 late gaps from projected coordinates. For gap-testing on other
1005 columns use [col]z; if col is not prepended the it defaults to 2
1006 (i.e., 3rd column). Append [+|-]gap and optionally a unit u.
1007 Regarding optional signs: -ve means previous minus current col‐
1008 umn value must exceed gap to be a gap, +ve means current minus
1009 previous column value must exceed gap, and no sign means the
1010 absolute value of the difference must exceed gap. For geographic
1011 data (x|y|d), the unit u may be arc degree, minute, or second,
1012 or meter [Default], foot, kilometer, Mile, nautical mile, or
1013 survey foot. For projected data (X|Y|D), choose from inch, cen‐
1014 timeter, or point [Default unit set by PROJ_LENGTH_UNIT]. Note:
1015 For x|y|z with time data the unit is instead controlled by
1016 TIME_UNIT. Repeat the option to specify multiple criteria, of
1017 which any can be met to produce a line break. Issue an addi‐
1018 tional -ga to indicate that all criteria must be met instead.
1019 -h[i|o][n][+c][+d][+rremark][+ttitle]
1021 Primary input file(s) has header record(s). If used, the default
1022 number of header records is IO_N_HEADER_RECS [1]. Use -hi if
1023 only the primary input data should have header records [Default
1024 will write out header records if the input data have them].
1025 Blank lines and lines starting with # are always skipped. For
1026 output you may request additional headers to be written via the
1027 option modifiers, and use +d to remove existing header records.
1028 Append +c to issue a header comment with column names to the
1029 output [none]. Append +r to add a remark comment to the output
1030 [none]. Append +t to add a title comment to the output [none].
1031 These optional strings may contain n to indicate line-breaks).
1032 If used with native binary data we interpret n to instead mean
1033 the number of bytes to skip on input or pad on output.
1034 -icols[+l][+sscale][+ooffset][,...]
1036 Select specific data columns for primary input, in arbitrary
1037 order. Columns not listed will be skipped. Give individual col‐
1038 umns (or column ranges in the format start[:inc ]:stop, where
1039 inc defaults to 1 if not specified) separated by commas [Default
1040 reads all columns in order, starting with the first column (0)].
1041 Columns may be repeated. To each column, optionally add any of
1042 the following: +l takes log10 of the input values first;
1043 +sscale, subsequently multiplies by a given scale factor [1];
1044 +ooffset, finally adds a given offset [0].
1045 -n[b|c|l|n][+a][+bBC][+c][+tthreshold]
1047 Select grid interpolation mode by adding b for B-spline smooth‐
1048 ing, c for bicubic interpolation, l for bilinear interpolation,
1049 or n for nearest-neighbor value (for example to plot categorical
1050 data). Optionally, append +a to switch off antialiasing (where
1051 supported). Append +bBC to override the boundary conditions
1052 used, adding g for geographic, p for periodic, or n for natural
1053 boundary conditions. For the latter two you may append x or y to
1054 specify just one direction, otherwise both are assumed. Append
1055 +c to clip the interpolated grid to input z-min/max [Default may
1056 exceed limits]. Append +tthreshold to control how close to nodes
1057 with NaNs the interpolation will go. A threshold of 1.0 requires
1058 all (4 or 16) nodes involved in interpolation to be non-NaN. 0.5
1059 will interpolate about half way from a non-NaN value; 0.1 will
1060 go about 90% of the way, etc. [Default is bicubic interpolation
1061 with antialiasing and a threshold of 0.5, using geographic (if
1062 grid is known to be geographic) or natural boundary conditions].
1063 -ocols[,...]
1065 Select specific data columns for primary output, in arbitrary
1066 order. Columns not listed will be skipped. Give columns (or col‐
1067 umn ranges in the format start[:inc ]:stop, where inc defaults
1068 to 1 if not specified) separated by commas. Columns may be
1069 repeated. [Default writes all columns in order].
1070 -p[x|y|z]azim[/elev[/zlevel]][+wlon0/lat0[/z0]][+vx0/y0]
1072 Selects perspective view and sets the azimuth and elevation of
1073 the viewpoint [180/90]. When -p is used in consort with -Jz or
1074 -JZ, a third value can be appended which indicates at which
1075 z-level all 2D material, like the plot frame, is plotted (in
1076 perspective). [Default is at the bottom of the z-axis]. Use -px
1077 or -py to plot against the "wall" x = level or y = level
1078 (default is on the horizontal plane, which is the same as using
1079 -pz). For frames used for animation, you may want to append + to
1080 fix the center of your data domain (or specify a particular
1081 world coordinate point with +wlon0/lat[/z]) which will project
1082 to the center of your page size (or specify the coordinates of
1083 the projected view point with +vx0/y0. When -p is used without
1084 any further arguments, the values from the last use of -p in a
1085 previous GMT command will be used. Alternatively, you can per‐
1086 form a simple rotation about the z-axis by just giving the rota‐
1087 tion angle. Optionally, use +v or +w to select another axis
1088 location than the plot origin.
1089 -r Force pixel node registration [Default is gridline registra‐
1091 tion]. (Node registrations are defined in Section grid-regis‐
1092 tration of the GMT Technical Reference and Cookbook.)
1093 -s[cols][a|r]
1095 Suppress output for records whose z-value equals NaN [Default
1096 outputs all records]. Append a to skip records where at least
1097 one field equal NaN. Append r to reverse the suppression, i.e.,
1098 only output the records whose z-value equals NaN. Alternatively,
1099 indicate a comma-separated list of all columns or column ranges
1100 to consider for this NaN test (Column ranges must be given in
1101 the format start[:inc ]:stop, where inc defaults to 1 if not
1102 specified).
1103 -t[transp]
1105 Set PDF transparency level for an overlay, in 0-100 percent
1106 range. [Default is 0, i.e., opaque].
1107 -x[[-]n]
1109 Limit the number of cores to be used in any OpenMP-enabled
1110 multi-threaded algorithms. By default we try to use all avail‐
1111 able cores. Append n to only use n cores (if too large it will
1112 be truncated to the maximum cores available). Finally, give a
1113 negative n to select (all - n) cores (or at least 1 if n equals
1114 or exceeds all). The -x option is only available to GMT modules
1115 compiled with OpenMP support.
1116 -:[i|o]
1118 Swap 1st and 2nd column on input and/or output [Default is no
1119 swapping]. Append i to select input only or o to select output
1120 only. [Default affects both]. This option is typically used to
1121 handle (latitude, longitude) files; see also
1122 -icols[l][sscale][ooffset][,...].
1123 -^ or just -
1125 Print a short message about the syntax of the command, then
1126 exits (NOTE: on Windows just use -).
1127 -+ or just +
1129 Print an extensive usage (help) message, including the explana‐
1130 tion of any module-specific option (but not the GMT common
1131 options), then exits.
1132 -? or no arguments
1134 Print a complete usage (help) message, including the explanation
1135 of all options, then exits.
1136 Specifying Color
1138 color The color of lines, areas and patterns can be specified by a
1139 valid color name, by a gray shade (in the range 0-255), by a
1140 decimal color code (r/g/b, each in range 0-255; h-s-v, ranges
1141 0-360, 0-1, 0-1; or c/m/y/k, each in range 0-1), or by a hexa‐
1142 decimal color code (#rrggbb, as used in HTML). For PDF trans‐
1143 parency, append @transparency in the 0-100 percent range [0 or
1144 opaque]. See gmtcolors for more information and a full list of
1145 color names.
1146 Specifying Fill
1148 fill The attribute fill specifies the solid shade or solid color (see
1149 Specifying Color above) or the pattern used for filling poly‐
1150 gons. Patterns are specified as ppattern, where pattern set the
1151 number of the built-in pattern (1-90) or the name of a raster
1152 image file. The optional +rdpi sets the resolution of the image
1153 [1200]. For 1-bit rasters: use upper case P for inverse video,
1154 or append +fcolor and/or +bcolor to specify fore- and background
1155 colors (use color = - for transparency). See GMT Cookbook &
1156 Technical Reference Appendix E for information on individual
1157 built-in patterns.
1158 Specifying Fonts
1160 font The attributes of text fonts as defined by font is a comma
1161 delimited list of size, fonttype and fill, each of which is
1162 optional. size is the font size (usually in points) but c or i
1163 can be added to indicate other units. fonttype is the name (case
1164 sensitive!) of the font or its equivalent numerical ID (e.g.,
1165 Helvetica-Bold or 1). fill specifies the gray shade, color or
1166 pattern of the text (see Specifying Fill above). Optionally, you
1167 may append =pen to the fill value in order to draw a text out‐
1168 line. If you want to avoid that the outline partially obscures
1169 the text, append append =~pen instead; in that case only half
1170 the linewidth is plotted on the outside of the font only. If an
1171 outline is requested, you may optionally skip the text fill by
1172 setting it to -, in which case the full pen width is always
1173 used. If any of the font attributes is omitted their default or
1174 previous setting will be retained.
1175 The 35 available fonts are:
1177 0. Helvetica
1179 1. Helvetica-Bold
1181 2. Helvetica-Oblique
1183 3. Helvetica-BoldOblique
1185 4. Times-Roman
1187 5. Times-Bold
1189 6. Times-Italic
1191 7. Times-BoldItalic
1193 8. Courier
1195 9. Courier-Bold
1197 10. Courier-Oblique
1199 11. Courier-BoldOblique
1201 12. Symbol
1203 13. AvantGarde-Book
1205 14. AvantGarde-BookOblique
1207 15. AvantGarde-Demi
1209 16. AvantGarde-DemiOblique
1211 17. Bookman-Demi
1213 18. Bookman-DemiItalic
1215 19. Bookman-Light
1217 20. Bookman-LightItalic
1219 21. Helvetica-Narrow
1221 22. Helvetica-Narrow-Bold
1223 23. Helvetica-Narrow-Oblique
1225 24. Helvetica-Narrow-BoldOblique
1227 25. NewCenturySchlbk-Roman
1229 26. NewCenturySchlbk-Italic
1231 27. NewCenturySchlbk-Bold
1233 28. NewCenturySchlbk-BoldItalic
1235 29. Palatino-Roman
1237 30. Palatino-Italic
1239 31. Palatino-Bold
1241 32. Palatino-BoldItalic
1243 33. ZapfChancery-MediumItalic
1245 34. ZapfDingbats
1247 Specifying Pens
1249 pen The attributes of lines and symbol outlines as defined by pen is
1250 a comma-delimited list of width, color and style, each of which
1251 is optional. width can be indicated as a measure (in points
1252 (this is the default), centimeters, or inches) or as faint,
1253 default, thin[ner|nest], thick[er|est], fat[ter|test], or obese.
1254 color specifies a gray shade or color (see Specifying Color
1255 above). style can be any of 'solid', 'dashed' or 'dotted', or a
1256 custom combination of dashes '-' and dots '.'. If any of the
1257 attributes is omitted their default or previous setting will be
1258 retained. See GMT Cookbook & Technical Reference Specifying pen
1259 attributes for more information.
1260
1262 The ASCII output formats of numerical data are controlled by parameters
1263 in your gmt.conf file. Longitude and latitude are formatted according
1264 to FORMAT_GEO_OUT, absolute time is under the control of FOR‐
1265 MAT_DATE_OUT and FORMAT_CLOCK_OUT, whereas general floating point val‐
1266 ues are formatted according to FORMAT_FLOAT_OUT. Be aware that the for‐
1267 mat in effect can lead to loss of precision in ASCII output, which can
1268 lead to various problems downstream. If you find the output is not
1269 written with enough precision, consider switching to binary output (-bo
1270 if available) or specify more decimals using the FORMAT_FLOAT_OUT set‐
1271 ting.
1272
1274 By default GMT writes out grid as single precision floats in a
1275 COARDS-complaint netCDF file format. However, GMT is able to produce
1276 and read grid files in many other commonly used grid file formats and
1277 also facilitates so called "packing" of grids, writing out floating
1278 point data as 1- or 2-byte integers. To specify the precision, scale
1279 and offset, the user should add the suffix =id[/scale/offset[/nan]],
1280 where id is a two-letter identifier of the grid type and precision, and
1281 scale and offset are optional scale factor and offset to be applied to
1282 all grid values, and nan is the value used to indicate missing data. In
1283 case the two characters id is not provided, as in =/scale than a id=nf
1284 is assumed. When reading grids, the format is generally automatically
1285 recognized from almost all of those formats that GMT and GDAL combined
1286 offer. If not, the same suffix can be added to input grid file names.
1287 See grdconvert and Section grid-file-format of the GMT Technical Refer‐
1288 ence and Cookbook for more information.
1289 When reading a netCDF file that contains multiple grids, GMT will read,
1291 by default, the first 2-dimensional grid that can find in that file. To
1292 coax GMT into reading another multi-dimensional variable in the grid
1293 file, append ?varname to the file name, where varname is the name of
1294 the variable. Note that you may need to escape the special meaning of ?
1295 in your shell program by putting a backslash in front of it, or by
1296 placing the filename and suffix between quotes or double quotes. The
1297 ?varname suffix can also be used for output grids to specify a variable
1298 name different from the default: "z". See grdconvert and Sections modi‐
1299 fiers-for-CF and grid-file-format of the GMT Technical Reference and
1300 Cookbook for more information, particularly on how to read splices of
1301 3-, 4-, or 5-dimensional grids.
1302
1304 Look up the individual man pages for more details and full syntax. Run
1305 gmt --help to list all GMT programs and to show all installation direc‐
1306 tories. For an explanation of the various GMT settings in this man page
1307 (like FORMAT_FLOAT_OUT), see the man page of the GMT configuration file
1308 gmt.conf. Information is also available on the GMT home page
1309 http://gmt.soest.hawaii.edu/
1310
1312 2019, P. Wessel, W. H. F. Smith, R. Scharroo, J. Luis, and F. Wobbe
13135.4.5 Feb 24, 2019 GMT(1)