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gmtdefaults - To list current GMT defaults


gmtdefaults -D[u|s] | -L


gmtdefaults lists the GMT parameter defaults if the option -D is used. To change some of the settings, use any texteditor to edit the file .gmtdefaults in your home or current directory. If you do not have this file in your home or current directory, run gmtdefaults -D > ~/.gmtdefaults to get the system settings. GMT can provide default values in US or SI units. This choice is determined by the contents of the gmt.conf file in GMT’s share directory.
Print the system GMT defaults to standard output. Append u for US defaults or s for SI defaults. [-D alone gives current choice in gmt.conf].
Print the user’s currently active defaults to standard output.


The following is a list of the 58 parameters that are user-definable in GMT. The parameter names are always given in UPPER CASE. The parameter values are case-insensitive unless otherwise noted. The system defaults are given in brackets [ ]. Those marked * can be set on the command line as well (the corresponding option is given in parentheses). Note that default distances and lengths below are given in both cm or inch; the chosen default depends on your choice of default unit (see MEASURE_UNIT). You can explicitly specify the unit used for distances and lengths by appending c (cm), i (inch), m (meter), or p {points). When no unit is indicated the value will be assumed to be in the unit set by MEASURE_UNIT. Note that the printer resolution DOTS_PR_INCH is always the number of dots or pixels per inch. Several parameters take only TRUE or FALSE.
If the angle between the map boundary and the annotation baseline is less than this minimum value (in degrees), the annotation is not plotted (this may occur for certain oblique projections.) Give a value in the range 0-90. [20]
If an annotation would be plotted less than this minimum distance from its closest neighbor, the annotation is not plotted (this may occur for certain oblique projections.) [0]
Font used for tick mark annotations etc [Helvetica]. Specify either the font number or the font name (case sensitive!). The 39 available fonts are:
   0 Helvetica

   1 Helvetica-Bold

   2 Helvetica-Oblique

   3 Helvetica-BoldOblique

   4 Times-Roman

   5 Times-Bold

   6 Times-Italic

   7 Times-BoldItalic

   8 Courier

   9 Courier-Bold

   10 Courier-Oblique

   11 Courier-BoldOblique

   12 Symbol

   13 AvantGarde-Book

   14 AvantGarde-BookOblique

   15 AvantGarde-Demi

   16 AvantGarde-DemiOblique

   17 Bookman-Demi

   18 Bookman-DemiItalic

   19 Bookman-Light

   20 Bookman-LightItalic

   21 Helvetica-Narrow

   22 Helvetica-Narrow-Bold

   23 Helvetica-Narrow-Oblique

   24 Helvetica-Narrow-BoldOblique

   25 NewCenturySchlbk-Roman

   26 NewCenturySchlbk-Italic

   27 NewCenturySchlbk-Bold

   28 NewCenturySchlbk-BoldItalic

   29 Palatino-Roman

   30 Palatino-Italic

   31 Palatino-Bold

   32 Palatino-BoldItalic

   33 ZapfChancery-MediumItalic

   34 ZapfDingbats

   35 Ryumin-Light-EUC-H

   36 Ryumin-Light-EUC-V

   37 GothicBBB-Medium-EUC-H

   38 GothicBBB-Medium-EUC-V
Font size (> 0) in points for map annotations. [14]
Distance from end of tickmark to start of annotation [0.2c (or 0.075i)]. A negative offset will place the anotation inside the map border.
Sets which axes to draw and annotate. Case sensitive: Upper case means both draw and annotate, lower case means draw axis only. [WESN].
Color used to draw map boundaries and annotations. Give a red/green/blue triplet, with each element in the 0-255 range. [0/0/0] (black).
Choose between plain and fancy (thick boundary, alternating black/white frame) [fancy]. For some map projections (e.g., Oblique Mercator), plain is the only option even if fancy is set as default.
Color used for the background of images (i.e., when z < lowest colortable entry). Give a red/green/blue triplet, with each element in the 0-255 range. [0/0/0] (black)
Color used for the foreground of images (i.e., when z > highest colortable entry). Give a red/green/blue triplet, with each element in the 0-255 range. [255/255/255] (white)
Selects which operator to use when rendering bit-mapped color images. Due to the lack of the colorimage operator in some PostScript implementations, GMT offers 2 different options:

   adobe (Adobe’s colorimage definition) [Default].

   tiles (Plot image as many individual rectangles).

Selects if color palette files contain rgb values (r,g,b in 0-255 range) or HSV values (h = 0-360, s,v in 0-1 range) [rgb].
Color used for the non-defined areas of images (i.e., where z == NaN). Give a red/green/blue triplet, with each element in the 0-255 range. [128/128/128] (gray)
Output format (C language syntax) to be used when printing double precision floating point numbers If it is NOT a ’g’-type format (as the default is), the format is used directly in anotations. [%lg].
Output format to be used when annotating map boundaries. Choose between six formats:

   0    Longitudes go from 0 to 360, latitudes from -90 to 90 [Default].

   1    Longitudes go from -180 to 180, latitudes from -90 to 90.

   2    Longitudes are unsigned 0 to 180, latitudes unsigned 0 to 90.

   3    Same as 2, but with letters W, E, S, or N appended as appropriate.

   4    Same as 0, with decimal degrees instead of degrees, minutes, and seconds.

   5    Same as 1, with decimal degrees instead of degrees, minutes, and seconds.

Add 10 to these values to use the large degree symbol character (octal 217) [Default is the small degree symbol (octal 312)].

Resolution of the plotting device (dpi). Note that in order to be as compact as possible, GMT PostScript output uses integer formats only so the resolution should be set depending on what output device you are using. E.g, using 300 and sending the output to a Linotype 300 phototypesetter (2470 dpi) will not take advantage of the extra resolution (i.e., positioning on the page and line thicknesses are still only done in steps of 1/300 inch; of course, text will look smoother) [300].
The (case sensitive) name of the ellipsoid used for the map projections [WGS-84]. Choose among

WGS-84        1984 World Geodetic System
GRS-80        1980 International Geodetic Reference System
WGS-72        1972 World Geodetic System
WGS-66        1966 World Geodetic System
Australian    1965 Used down under
Krassovsky    1940 Used in the Soviet Union
International    1924 Worldwide use
Hayford-1909    1909 Same as the International 1924
Clarke-1880    1880 Most of Africa, France
Clarke-1866    1866 North America, the Phillipines
Airy        1830 Great Britain
Bessel        1841 Central Europe, Chile, Indonesia
Everest        1830 India, Burma, Pakistan, Afghanistan, Thailand, etc.
Sphere        1980 The mean radius in GRS-80 (for spherical/plate tectonics applications)

Note that for some global projections, GMT may default to GRS-80 Sphere regardless of ellipsoid actually chosen. A warning will be given when this happens. If a different ellipsoid name than those mentioned here is given, GMT will attempt to open this name as a file and read the ellipsoid name, year, major-axis (in m), minor-axis (in m), and flattening from the first record, where the fields must be separated by white-space (not commas). This way a custom ellipsoid (e.g., those used for other planets) may be used.

Thickness of pen used to draw plain map frame in dpi units or points (append p) [5].
Width (> 0) of map borders for fancy map frame [0.2c (or 0.075i)].
Global x-scale (> 0) to apply to plot-coordinates before plotting. Normally used to shrink the entire output down to fit a specific height/width [1.0].
Same, but for y-coordinates [1.0].
Size (>= 0) of grid cross at lon-lat intersections. 0 means draw continuous gridlines instead [0].
Pen thickness used to draw grid lines in dpi units or points (append p) [1].
If TRUE, all gridfile names are examined to see if they use the file extension shorthand discussed in Section 4.17 of the GMT Technical Reference and Cookbook. If FALSE, no filename expansion is done [FALSE].
Font to use when plotting headers. See ANOT_FONT for available fonts [Helvetica].
Font size (> 0) for header in points [36].
Minimum saturation (0-1) assigned for most negative intensity value [1.0].
Maximum saturation (0-1) assigned for most positive intensity value [0.1].
Minimum value (0-1) assigned for most negative intensity value [0.3].
Maximum value (0-1) assigned for most positive intensity value [1.0].
Determines if linear (linear), Akima’s spline (akima), or natural cubic spline (cubic) should be used for 1-D interpolations in various programs [akima].
Specifies whether input/output ASCII files have header record(s) or not [FALSE].
Specifies how many header records to expect if -H is turned on [1].
Font to use when plotting labels below axes. See ANOT_FONT for available fonts [Helvetica].
Font size (> 0) for labels in points [24].
Determines the maximum length (> 0) of individual straight line-segments when drawing arcuate lines [0.025c (or 0.01i)]
Sets the central scale factor (> 0) used for the Polar Stereographic and Transverse Mercator projections. Typically, it is set to 0.9996 to minimize areal distortion [0.9996].
Sets the height (> 0) on the map of the map scalebars drawn by various programs [0.2c (or 0.075i)].
Sets the unit length. Choose between cm, inch, m, and point. [cm]. Note that, in GMT, one point is defined as 1/72 inch (the PostScript definition), while it is often defined as 1/72.27 inch in the typesetting industry. There is no universal definition.
N_COPIES * (-c)
Number of plot copies to make [1].
This integer is a sum of 5 bit flags (most of which only are relevant for oblique projections): If bit 1 is set (1) , annotations will occur wherever a gridline crosses the map boundaries, else longitudes will be annotated on the lower and upper boundaries only, and latitudes will be annotated on the left and right boundaries only. If bit 2 is set (2) , then longitude anotations will be plotted horizontally. If bit 3 is set (4) , then latitude anotations will be plotted horizontally. If bit 4 is set (8) , then oblique tickmarks are extended to give a projection equal to the specified tick_length. If bit 5 is set (16), tickmarks will be drawn normal to the border regardless of gridline angle. To set a combination of these, add up the values in parentheses. [1].
Sets the color of the imaging background, i.e., the paper. Give a red/green/blue triplet, with each element in the 0-255 range. [255/255/255] (white)
Sets the orientation of the page. Choose portrait or landscape [landscape].
Sets the physical format of the current plot paper [A4]. The following formats (and their widths and heights in points) are recognized (Additional site-specific formats may be specified in the gmtmedia.d file in $GMTHOME/share; see that file for details):

   Media    width    height

   A0    2380    3368

   A1    1684    2380

   A2    1190    1684

   A3    842    1190

   A4    595    842

   A5    421    595

   A6    297    421

   A7    210    297

   A8    148    210

   A9    105    148

   A10    74    105

   B0    2836    4008

   B1    2004    2836

   B2    1418    2004

   B3    1002    1418

   B4    709    1002

   B5    501    709

   archA    648    864

   archB    864    1296

   archC    1296    1728

   archD    1728    2592

   archE    2592    3456

   flsa    612    936

   halfletter    396    612

   note    540    720

   letter    612    792

   legal    612    1008

   11x17    792    1224

   ledger    1224    792

To force the printer to request a manual paper feed, append ’-’ to the media name, e.g., A3- will require the user to insert a A3 paper into the printer’s manual feed slot. To indicate you are making an EPS file, append ’+’ to the media name. Then, GMT will attempt to issue a tight bounding box [Default is the paper dimension].

Determines whether images created in PostScript should use hexadecimal (i.e., ascii) or binary format. The latter takes up only half as much space and executes faster but may choke some printers, especially those off serial ports. Select hex or bin [hex].
The length of a tickmark. Normally, tickmarks are drawn on the outside of the map boundaries. To select interior tickmarks, use a negative tick_length [0.2c (or 0.075i)].
The pen thickness to be used for tickmarks in dpi units or points (append p) [2].
Specifies if a UNIX system time stamp should be plotted at the lower left corner of the plot [FALSE].
Sets the position of the UNIX time stamp relative to the current plots lower left corner [-2c/-2c (or -0.75i/-0.75i)].
Determines the shape of the head of a vector. Normally (i.e., for vector_shape = 0), the head will be triangular, but can be changed to an arrow (1) . Intermediate settings gives something in between [0].
Determines if GMT programs should display run-time information or run silently [FALSE].
Determines if GMT PostScript output should include font re-encoding for accented European characters. See Cookbook section 4.16 and Appendix H for details [TRUE].
Sets the default length (> 0) of the x-axis [25c (or 9i)].
Sets the default length (> 0) of the y-axis [15c (or 6i)].
Sets the x-coordinate of the origin on the paper for a new plot [2.5c (or 1i)]. For an overlay, the default offset is 0.
Sets the y-coordinate of the origin on the paper for a new plot [2.5c (or 1i)]. For an overlay, the default offset is 0.
XY_TOGGLE * (-:)
Set if the first two columns of input files contain (latitude,longitude) or (y,x) rather than the expected (longitude,latitude) or (x,y) [FALSE].
Determines if the annotations for a y-axis (for linear projections) should be plotted horizontally (hor_text) or vertically (ver_text) [hor_text].


To get a copy of the GMT parameter defaults in your home directory, run

gmtdefaults -D > ~/.gmtdefaults

You may now change the settings by editing this file using a text editor of your choice, or use gmtset to change specified parameters on the command line.


If you have typographical errors in your .gmtdefaults file(s), a warning message will be issued, and the GMT defaults for the affected parameters will be used.

See Also

gmt(3) , gmtset(3)

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