Provided by: gmt-common_5.4.3+dfsg-1_all bug

NAME

       gmt - The Generic Mapping Tools data processing and display software package

INTRODUCTION

       GMT  is  a  collection  of  public-domain Unix tools that allows you to manipulate x,y and
       x,y,z data sets  (filtering,  trend  fitting,  gridding,  projecting,  etc.)  and  produce
       PostScript  illustrations ranging from simple x-y plots, via contour maps, to artificially
       illuminated surfaces and 3-D perspective views  in  black/white  or  full  color.  Linear,
       log10,  and  power scaling is supported in addition to over 30 common map projections. The
       processing and display routines within GMT are completely  general  and  will  handle  any
       (x,y) or (x,y,z) data as input.

SYNOPSIS

       gmt is the main program that can start any of the modules:

       gmt module module-options

       where  module  is  the name of a GMT module and the options are those that pertain to that
       particular module.  A few special modules are also available:

       gmt clear items

       while delete the user’s history.  Choose between history (deletes the gmt.history file  in
       the  current  directory), conf (deletes the gmt.conf file in the current directory), cache
       (deletes the user’s cache directory and all of its content),  or  all  (does  all  of  the
       above).

       If no module is given then several other options are available:

       --help List and description of GMT modules.

       --show-cores
              Show number of available cores.

       --show-bindir
              Show directory of executables and exit.

       --show-datadir
              Show data directory/ies and exit.

       --show-modules
              List module names on stdout and exit.

       --show-plugindir
              Show plugin directory and exit.

       --show-sharedir
              Show share directory and exit.

       --version
              Print version and exit.

       =      Check  if  that  module  exist  and  if  so the program will exit with status of 0;
              otherwise the status of exit will be non-zero.

COMMAND-LINE COMPLETION

       GMT provides basic command-line completion (tab  completion)  for  bash.   The  completion
       rules       are      either      installed      in      /etc/bash_completion.d/gmt      or
       <prefix>/share/tools/gmt_completion.bash.  Depending on the distribution,  you  may  still
       need  to  source  the  gmt completion file from ~/.bash_completion or ~/.bashrc.  For more
       information see Section command-line-completion in the CookBook.

GMT OVERVIEW

       The following is a summary of all  the  programs  supplied  with  GMT  and  a  very  short
       description  of their purpose. Detailed information about each program can be found in the
       separate manual pages.

                                ┌───────────────┬───────────────────────┐
                                │blockmean      │                       │
                                ├───────────────┼───────────────────────┤
                                │blockmedian    │                       │
                                ├───────────────┼───────────────────────┤
                                │blockmode      │                       │
                                ├───────────────┼───────────────────────┤
                                │filter1d       │                       │
                                ├───────────────┼───────────────────────┤
                                │fitcircle      │                       │
                                ├───────────────┼───────────────────────┤
                                │gmt2kml        │                       │
                                ├───────────────┼───────────────────────┤
                                │gmtconnect     │                       │
                                ├───────────────┼───────────────────────┤
                                │gmtconvert     │                       │
                                ├───────────────┼───────────────────────┤
                                │gmtdefaults    │                       │
                                ├───────────────┼───────────────────────┤
                                │gmtget         │                       │
                                ├───────────────┼───────────────────────┤
                                │gmtinfo        │                       │
                                ├───────────────┼───────────────────────┤
                                │gmtmath        │                       │
                                ├───────────────┼───────────────────────┤
                                │gmtselect      │                       │
                                ├───────────────┼───────────────────────┤
                                │gmtset         │                       │
                                ├───────────────┼───────────────────────┤
                                │gmtspatial     │                       │
                                ├───────────────┼───────────────────────┤
                                │gmtsimplify    │                       │
                                ├───────────────┼───────────────────────┤
                                │gmtvector      │                       │
                                ├───────────────┼───────────────────────┤
                                │gmtwhich       │                       │
                                ├───────────────┼───────────────────────┤
                                │grd2cpt        │                       │
                                ├───────────────┼───────────────────────┤
                                │grd2rgb        │                       │
                                ├───────────────┼───────────────────────┤
                                │grd2xyz        │                       │
                                ├───────────────┼───────────────────────┤
                                │grdblend       │                       │
                                ├───────────────┼───────────────────────┤
                                │grdclip        │                       │
                                ├───────────────┼───────────────────────┤
                                │grdcontour     │                       │
                                ├───────────────┼───────────────────────┤
                                │grdconvert     │                       │
                                ├───────────────┼───────────────────────┤
                                │grdcut         │                       │
                                ├───────────────┼───────────────────────┤
                                │grdedit        │                       │
                                ├───────────────┼───────────────────────┤
                                │grdfft         │                       │
                                ├───────────────┼───────────────────────┤
                                │grdfilter      │                       │
                                └───────────────┴───────────────────────┘

                                │grdgradient    │                       │
                                ├───────────────┼───────────────────────┤
                                │grdhisteq      │                       │
                                ├───────────────┼───────────────────────┤
                                │grdimage       │                       │
                                ├───────────────┼───────────────────────┤
                                │grdinfo        │                       │
                                ├───────────────┼───────────────────────┤
                                │grdlandmask    │                       │
                                ├───────────────┼───────────────────────┤
                                │grdmask        │                       │
                                ├───────────────┼───────────────────────┤
                                │grdmath        │                       │
                                ├───────────────┼───────────────────────┤
                                │grdpaste       │                       │
                                ├───────────────┼───────────────────────┤
                                │grdproject     │                       │
                                ├───────────────┼───────────────────────┤
                                │grdraster      │                       │
                                ├───────────────┼───────────────────────┤
                                │grdsample      │                       │
                                ├───────────────┼───────────────────────┤
                                │grdtrack       │                       │
                                ├───────────────┼───────────────────────┤
                                │grdtrend       │                       │
                                ├───────────────┼───────────────────────┤
                                │grdvector      │                       │
                                ├───────────────┼───────────────────────┤
                                │grdview        │                       │
                                ├───────────────┼───────────────────────┤
                                │grdvolume      │                       │
                                ├───────────────┼───────────────────────┤
                                │greenspline    │                       │
                                ├───────────────┼───────────────────────┤
                                │kml2gmt        │                       │
                                ├───────────────┼───────────────────────┤
                                │makecpt        │                       │
                                ├───────────────┼───────────────────────┤
                                │mapproject     │                       │
                                ├───────────────┼───────────────────────┤
                                │nearneighbor   │                       │
                                ├───────────────┼───────────────────────┤
                                │project        │                       │
                                ├───────────────┼───────────────────────┤
                                │psbasemap      │                       │
                                ├───────────────┼───────────────────────┤
                                │psclip         │                       │
                                ├───────────────┼───────────────────────┤
                                │pscoast        │                       │
                                ├───────────────┼───────────────────────┤
                                │pscontour      │                       │
                                ├───────────────┼───────────────────────┤
                                │psconvert      │                       │
                                ├───────────────┼───────────────────────┤
                                │pshistogram    │                       │
                                ├───────────────┼───────────────────────┤
                                │psimage        │                       │
                                ├───────────────┼───────────────────────┤
                                │pslegend       │                       │
                                ├───────────────┼───────────────────────┤
                                │psmask         │                       │
                                ├───────────────┼───────────────────────┤
                                │psrose         │                       │
                                └───────────────┴───────────────────────┘

                                │psscale        │                       │
                                ├───────────────┼───────────────────────┤
                                │pstext         │                       │
                                ├───────────────┼───────────────────────┤
                                │pswiggle       │                       │
                                ├───────────────┼───────────────────────┤
                                │psxy           │                       │
                                ├───────────────┼───────────────────────┤
                                │psxyz          │                       │
                                ├───────────────┼───────────────────────┤
                                │sample1d       │                       │
                                ├───────────────┼───────────────────────┤
                                │spectrum1d     │                       │
                                ├───────────────┼───────────────────────┤
                                │splitxyz       │                       │
                                ├───────────────┼───────────────────────┤
                                │surface        │                       │
                                ├───────────────┼───────────────────────┤
                                │trend1d        │                       │
                                ├───────────────┼───────────────────────┤
                                │trend2d        │                       │
                                ├───────────────┼───────────────────────┤
                                │triangulate    │                       │
                                ├───────────────┼───────────────────────┤
                                │xyz2grd        │                       │
                                ├───────────────┼───────────────────────┤
                                │               │ Supplement gshhg:     │
                                ├───────────────┼───────────────────────┤
                                │gshhg          │                       │
                                ├───────────────┼───────────────────────┤
                                │               │ Supplement img:       │
                                ├───────────────┼───────────────────────┤
                                │img2grd        │                       │
                                ├───────────────┼───────────────────────┤
                                │               │ Supplement meca:      │
                                ├───────────────┼───────────────────────┤
                                │pscoupe        │                       │
                                ├───────────────┼───────────────────────┤
                                │psmeca         │                       │
                                ├───────────────┼───────────────────────┤
                                │pspolar        │                       │
                                ├───────────────┼───────────────────────┤
                                │psvelo         │                       │
                                ├───────────────┼───────────────────────┤
                                │pssac          │                       │
                                ├───────────────┼───────────────────────┤
                                │               │ Supplement mgd77:     │
                                ├───────────────┼───────────────────────┤
                                │mgd77convert   │                       │
                                ├───────────────┼───────────────────────┤
                                │mgd77header    │                       │
                                ├───────────────┼───────────────────────┤
                                │mgd77info      │                       │
                                ├───────────────┼───────────────────────┤
                                │mgd77list      │                       │
                                ├───────────────┼───────────────────────┤
                                │mgd77magref    │                       │
                                ├───────────────┼───────────────────────┤
                                │mgd77manage    │                       │
                                ├───────────────┼───────────────────────┤
                                │mgd77path      │                       │
                                ├───────────────┼───────────────────────┤
                                │mgd77sniffer   │                       │
                                └───────────────┴───────────────────────┘

                                │mgd77track     │                       │
                                ├───────────────┼───────────────────────┤
                                │               │ Supplement potential: │
                                ├───────────────┼───────────────────────┤
                                │gmtgravmag3d   │                       │
                                ├───────────────┼───────────────────────┤
                                │gmtflexure     │                       │
                                ├───────────────┼───────────────────────┤
                                │gpsgridder     │                       │
                                ├───────────────┼───────────────────────┤
                                │gravfft        │                       │
                                ├───────────────┼───────────────────────┤
                                │grdflexure     │                       │
                                ├───────────────┼───────────────────────┤
                                │grdgravmag3d   │                       │
                                ├───────────────┼───────────────────────┤
                                │grdredpol      │                       │
                                ├───────────────┼───────────────────────┤
                                │grdseamount    │                       │
                                ├───────────────┼───────────────────────┤
                                │talwani2d      │                       │
                                ├───────────────┼───────────────────────┤
                                │talwani3d      │                       │
                                ├───────────────┼───────────────────────┤
                                │               │ Supplement segy:      │
                                ├───────────────┼───────────────────────┤
                                │pssegy         │                       │
                                ├───────────────┼───────────────────────┤
                                │pssegyz        │                       │
                                ├───────────────┼───────────────────────┤
                                │segy2grd       │                       │
                                ├───────────────┼───────────────────────┤
                                │               │ Supplement sph:       │
                                ├───────────────┼───────────────────────┤
                                │sphdistance    │                       │
                                ├───────────────┼───────────────────────┤
                                │sphinterpolate │                       │
                                ├───────────────┼───────────────────────┤
                                │sphtriangulate │                       │
                                ├───────────────┼───────────────────────┤
                                │               │ Supplement spotter:   │
                                ├───────────────┼───────────────────────┤
                                │backtracker    │                       │
                                ├───────────────┼───────────────────────┤
                                │gmtpmodeler    │                       │
                                ├───────────────┼───────────────────────┤
                                │grdpmodeler    │                       │
                                ├───────────────┼───────────────────────┤
                                │grdrotater     │                       │
                                ├───────────────┼───────────────────────┤
                                │grdspotter     │                       │
                                ├───────────────┼───────────────────────┤
                                │hotspotter     │                       │
                                ├───────────────┼───────────────────────┤
                                │originator     │                       │
                                ├───────────────┼───────────────────────┤
                                │rotconverter   │                       │
                                ├───────────────┼───────────────────────┤
                                │rotsmoother    │                       │
                                ├───────────────┼───────────────────────┤
                                │               │ Supplement x2sys:     │
                                ├───────────────┼───────────────────────┤
                                │x2sys_binlist  │                       │
                                └───────────────┴───────────────────────┘

                                │x2sys_cross    │                       │
                                ├───────────────┼───────────────────────┤
                                │x2sys_datalist │                       │
                                ├───────────────┼───────────────────────┤
                                │x2sys_get      │                       │
                                ├───────────────┼───────────────────────┤
                                │x2sys_init     │                       │
                                ├───────────────┼───────────────────────┤
                                │x2sys_list     │                       │
                                ├───────────────┼───────────────────────┤
                                │x2sys_merge    │                       │
                                ├───────────────┼───────────────────────┤
                                │x2sys_put      │                       │
                                ├───────────────┼───────────────────────┤
                                │x2sys_report   │                       │
                                ├───────────────┼───────────────────────┤
                                │x2sys_solve    │                       │
                                └───────────────┴───────────────────────┘

CUSTOM MODULES

       The gmt program can also load custom modules from shared libraries built as  specified  in
       the  GMT API documentation.  This way your modules can benefit form the GMT infrastructure
       and extend GMT in specific ways.

THE COMMON GMT OPTIONS

        -B[p|s]parameters -Jparameters -Jz|Zparameters -K -O -P
        -Rwest/east/south/north[/zmin/zmax][+r]
        -U[stamp]
        -V[level]
        -Xx_offset
        -Yy_offset -aflags -bbinary -dnodata -fflags -ggaps -hheaders -iflags -nflags -oflags -p‐
       flags -r -sflags -ttransp -x[[-]n] -:[i|o]

DESCRIPTION

       These  are  all the common GMT options that remain the same for all GMT programs. No space
       between the option flag and the associated arguments.

       -B[p|s]parameters
              Set map Frame and Axes parameters. The Frame parameters are specified by

              -B[axes][+b][+gfill][+n][+olon/lat][+ttitle]

              where axes selects which axes to plot. By default, all 4 map  boundaries  (or  plot
              axes)  are plotted (named W, E, S, N). To customize, append the codes for those you
              want (e.g., WSn). Upper case means plot and annotate while lower  case  just  plots
              the specified axes.  If a 3-D basemap is selected with -p and -Jz, append Z or z to
              control the appearance of the vertical axis. By default a single vertical axes will
              be  plotted  at the most suitable map corner. Override the default by appending any
              combination of corner ids 1234, where 1 represents the lower left  corner  and  the
              order goes counter-clockwise. Append +b to draw the outline of the 3-D cube defined
              by -R; this modifier is also needed to display gridlines in the  x-z,  y-z  planes.
              Note  that for 3-D views the title, if given, will be suppressed. You can paint the
              interior of the canvas with +gfill.  Append +n to have no frame and annotations  at
              all  [Default  is  controlled by the codes].  Optionally append +oplon/plat to draw
              oblique gridlines about specified pole [regular gridlines].  Ignored  if  gridlines
              are  not  requested (below) and disallowed for the oblique Mercator projection.  To
              add a plot title (+ttitle). The Frame setting is optional but can be  invoked  once
              to override the above defaults.

              The Axes parameters are specified by

              -B[p|s][x|y|z]intervals[+l|Llabel][+pprefix][+uunit]

              but you may also split this into two separate invocations for clarity, i.e.,

       · -B[p|s][x|y|z][+l|Llabel][+pprefix][+uunit]

       · -B[p|s][x|y|z]intervals

         The  first  optional flag following -B selects p (rimary) [Default] or s (econdary) axes
         information (mostly used for time axes annotations).  The [x|y|z]  flags  specify  which
         axes  you  are  providing information for.  If none are given then we default to xy.  If
         you wish to give different annotation intervals or labels for the various axes then  you
         must  repeat  the  B option for each axis (If a 3-D basemap is selected with -p and -Jz,
         use -Bz to give settings for the vertical axis.).  To add  a  label  to  an  axis,  just
         append  +llabel  (Cartesian  projections  only).  Use +L to force a horizontal label for
         y-axes (useful for very short labels).  If the axis annotation  should  have  a  leading
         text  prefix  (e.g.,  dollar  sign  for  those  plots  of your net worth) you can append
         +pprefix. For geographic maps the addition of degree symbols,  etc.  is  automatic  (and
         controlled  by the GMT default setting FORMAT_GEO_MAP). However, for other plots you can
         add specific units by adding +uunit.  If any of these text  strings  contain  spaces  or
         special characters you will need to enclose them in quotes.  The intervals specification
         is a concatenated string made up of substrings of the form

         [a|f|g]stride[+-phase][u].

         The leading a is used to specify the annotation and major tick spacing [Default], f  for
         minor  tick  spacing, and g for gridline spacing. stride is the desired stride interval.
         The optional phase shifts the annotation interval by that amount (positive or negative).
         The optional unit indicates the unit of the stride and can be any of

         · Y (year, plot with 4 digits)

         · y (year, plot with 2 digits)

         · O (month, plot using FORMAT_DATE_MAP)

         · o (month, plot with 2 digits)

         · U (ISO week, plot using FORMAT_DATE_MAP)

         · u (ISO week, plot using 2 digits)

         · r (Gregorian week, 7-day stride from start of week TIME_WEEK_START)

         · K (ISO weekday, plot name of day)

         · D (date, plot using FORMAT_DATE_MAP)

         · d (day, plot day of month 0-31 or year 1-366, via FORMAT_DATE_MAP)

         · R (day, same as d, aligned with TIME_WEEK_START)

         · H (hour, plot using FORMAT_CLOCK_MAP)

         · h (hour, plot with 2 digits)

         · M (minute, plot using FORMAT_CLOCK_MAP)

         · m (minute, plot with 2 digits)

         · S (second, plot using FORMAT_CLOCK_MAP)

         · s (second, plot with 2 digits).

         Note for geographic axes m and s instead mean arc minutes and arc seconds.  All entities
         that are language-specific are under control by GMT_LANGUAGE. Alternatively, for  linear
         maps,  we can omit stride, thus setting xinfo, yinfo, or zinfo to a plots annotations at
         automatically determined intervals,

         · ag plots both annotations and grid lines with the same spacing,

         · afg adds suitable minor tick intervals,

         · g plots grid lines with the same interval as if -Bf was used.

         For custom annotations and intervals, let intervals be given as cintfile, where  intfile
         contains  any  number  of  records  with  coord  type [label]. Here, type is one or more
         letters from a|i, f, and g. For a|i you must supply a label that will be plotted at  the
         coord  location.  For non-geographical projections: Give negative scale (in -Jx) or axis
         length (in -JX) to change the direction of increasing coordinates  (i.e.,  to  make  the
         y-axis  positive  down).   For  log10 axes: Annotations can be specified in one of three
         ways:

         1. stride can be 1,  2,  3,  or  -n.  Annotations  will  then  occur  at  1,  1-2-5,  or
            1-2-3-4-…-9,  respectively;  for  -n we annotate every n’t magnitude. This option can
            also be used for the frame and grid intervals.

         2. An l is appended to the tickinfo string. Then, log10 of the tick value is plotted  at
            every integer log10 value.

         3. A  p  is  appended  to  the tickinfo string. Then, annotations appear as 10 raised to
            log10 of the tick value.

         For power axes: Annotations can be specified in one of two ways:

         1. stride sets the regular annotation interval.

         2. A p is appended to the tickinfo string. Then, the annotation interval is expected  to
            be  in  transformed  units, but the annotation value will be plotted as untransformed
            units. E.g., if stride = 1 and power = 0.5 (i.e., sqrt), then equidistant annotations
            labeled 1-4-9…  will appear.

         These GMT parameters can affect the appearance of the map boundary: MAP_ANNOT_MIN_ANGLE,
         MAP_ANNOT_MIN_SPACING,             FONT_ANNOT_PRIMARY,             FONT_ANNOT_SECONDARY,
         MAP_ANNOT_OFFSET_PRIMARY,  MAP_ANNOT_OFFSET_SECONDARY,  MAP_ANNOT_ORTHO, MAP_FRAME_AXES,
         MAP_DEFAULT_PEN,   MAP_FRAME_TYPE,   FORMAT_GEO_MAP,   MAP_FRAME_PEN,   MAP_FRAME_WIDTH,
         MAP_GRID_CROSS_SIZE_PRIMARY,     MAP_GRID_PEN_PRIMARY,    MAP_GRID_CROSS_SIZE_SECONDARY,
         MAP_GRID_PEN_SECONDARY,  FONT_TITLE,   FONT_LABEL,   MAP_LINE_STEP,   MAP_ANNOT_OBLIQUE,
         FORMAT_CLOCK_MAP,  FORMAT_DATE_MAP,  FORMAT_TIME_PRIMARY_MAP, FORMAT_TIME_SECONDARY_MAP,
         GMT_LANGUAGE, TIME_WEEK_START, MAP_TICK_LENGTH_PRIMARY,  and  MAP_TICK_PEN_PRIMARY;  see
         the gmt.conf man page for details.

       -Jparameters

       Select map projection. The following character determines the projection. If the character
       is upper case then the argument(s) supplied as scale(s) is interpreted to be the map width
       (or  axis  lengths),  else  the scale argument(s) is the map scale (see its definition for
       each projection). UNIT is cm, inch, or point, depending on the PROJ_LENGTH_UNIT setting in
       gmt.conf,  but  this  can be overridden on the command line by appending c, i, or p to the
       scale or width values. Append h, +, or - to the given width if you instead want to set map
       height,  the  maximum  dimension, or the minimum dimension, respectively [Default is w for
       width].  In case the central meridian is an optional parameter and it  is  being  omitted,
       then  the  center  of  the  longitude  range  given  by the -R option is used. The default
       standard parallel  is  the  equator.   The  ellipsoid  used  in  the  map  projections  is
       user-definable  by  editing  the  gmt.conf  file  in your home directory. 73 commonly used
       ellipsoids and spheroids are currently supported, and users may  also  specify  their  own
       custom  ellipsoid  parameters  [Default is WGS-84].  Several GMT parameters can affect the
       projection: PROJ_ELLIPSOID, GMT_INTERPOLANT, PROJ_SCALE_FACTOR, and PROJ_LENGTH_UNIT;  see
       the  gmt.conf  man  page for details.  Choose one of the following projections (The E or C
       after projection names stands for Equal-Area and Conformal, respectively):
          CYLINDRICAL PROJECTIONS:
          -Jclon0/lat0/scale or -JClon0/lat0/width (Cassini).
              Give projection center lon0/lat0 and scale (1:xxxx or UNIT/degree).
          -Jcyl_stere/[lon0/[lat0/]]scale   or    -JCyl_stere/[lon0/[lat0/]]width    (Cylindrical
          Stereographic).
              Give central meridian lon0 (optional), standard parallel lat0 (optional), and scale
              along parallel (1:xxxx or UNIT/degree). The standard parallel is typically  one  of
              these (but can be any value):

                 · 66.159467 - Miller’s modified Gall

                 · 55 - Kamenetskiy’s First

                 · 45 - Gall’s Stereographic

                 · 30 - Bolshoi Sovietskii Atlas Mira or Kamenetskiy’s Second

                 · 0 - Braun’s Cylindrical
          -Jj[lon0/]scale or -JJ[lon0/]width (Miller Cylindrical Projection).
              Give the central meridian lon0 (optional) and scale (1:xxxx or UNIT/degree).
          -Jm[lon0/[lat0/]]scale or -JM[lon0/[lat0/]]width (Mercator [C])
              Give central meridian lon0 (optional), standard parallel lat0 (optional), and scale
              along parallel (1:xxxx or UNIT/degree).
          -Joparameters (Oblique Mercator [C]).
              Typically used with -RLLx/LLy/URx/URyr or with projected coordinates.  Specify  one
              of:

              -Jo[a|A]lon0/lat0/azimuth/scale or -JO[a|A]lon0/lat0/azimuth/width
                     Set projection center lon0/lat0, azimuth of oblique equator, and scale.

              -Jo[b|B]lon0/lat0/lon1/lat1/scale or -JO[b|B]lon0/lat0/lon1/lat1/scale
                     Set  projection  center  lon0/lat0,  another  point  on  the oblique equator
                     lon1/lat1, and scale.

              -Joc|Clon0/lat0/lonp/latp/scale or -JOc|Clon0/lat0/lonp/latp/scale
                     Set projection center lon0/lat0, pole of oblique projection  lonp/latp,  and
                     scale.   Give  scale  along  oblique  equator  (1:xxxx or UNIT/degree).  The
                     upper-case A|B|C to removes enforcement of a northern hemisphere pole.
          -Jq[lon0/[lat0/]]scale or -JQ[lon0/[lat0/]]width (Cylindrical Equidistant).
              Give the central meridian lon0 (optional), standard parallel lat0  (optional),  and
              scale (1:xxxx or UNIT/degree). The standard parallel is typically one of these (but
              can be any value):

                 · 61.7 - Grafarend and Niermann, minimum linear distortion

                 · 50.5 - Ronald Miller Equirectangular

                 · 43.5 - Ronald Miller, minimum continental distortion

                 · 42 - Grafarend and Niermann

                 · 37.5 - Ronald Miller, minimum overall distortion

                 · 0 - Plate Carree, Simple Cylindrical, Plain/Plane Chart
          -Jtlon0/[lat0/]scale or -JTlon0/[lat0/]width (Transverse Mercator [C])
              Give the central meridian lon0, central parallel lat0 (optional), and scale (1:xxxx
              or UNIT/degree).
          -Juzone/scale or -JUzone/width (UTM - Universal Transverse Mercator [C]).
              Give  the  UTM zone (A,B,1-60[C-X],Y,Z)) and scale (1:xxxx or UNIT/degree).  Zones:
              If C-X not given, prepend -  or  +  to  enforce  southern  or  northern  hemisphere
              conventions [northern if south > 0].
          -Jy[lon0/[lat0/]]scale or -JY[lon0/[lat0/]]width (Cylindrical Equal-Area [E]).
              Give  the  central meridian lon0 (optional), standard parallel lat0 (optional), and
              scale (1:xxxx or UNIT/degree). The standard parallel is typically one of these (but
              can be any value):

                 · 50 - Balthasart

                 · 45 - Gall-Peters

                 · 37.0666 - Caster

                 · 37.4 - Trystan Edwards

                 · 37.5 - Hobo-Dyer

                 · 30 - Behrman

                 · 0 - Lambert (default)

          CONIC PROJECTIONS:

          -Jblon0/lat0/lat1/lat2/scale or -JBlon0/lat0/lat1/lat2/width (Albers [E]).
                 Give  projection  center  lon0/lat0, two standard parallels lat1/lat2, and scale
                 (1:xxxx or UNIT/degree).

          -Jdlon0/lat0/lat1/lat2/scale or -JDlon0/lat0/lat1/lat2/width (Conic Equidistant)
                 Give projection center lon0/lat0, two standard parallels  lat1/lat2,  and  scale
                 (1:xxxx or UNIT/degree).

          -Jllon0/lat0/lat1/lat2/scale or -JLlon0/lat0/lat1/lat2/width (Lambert [C])
                 Give  origin  lon0/lat0, two standard parallels lat1/lat2, and scale along these
                 (1:xxxx or UNIT/degree).

          -Jpoly/[lon0/[lat0/]]scale or -JPoly/[lon0/[lat0/]]width ((American) Polyconic).
                 Give the central meridian lon0 (optional), reference  parallel  lat0  (optional,
                 default = equator), and scale along central meridian (1:xxxx or UNIT/degree).

          AZIMUTHAL PROJECTIONS:

          Except  for  polar  aspects,  -Rw/e/s/n  will  be reset to -Rg.  Use -R<…>r for smaller
          regions.

          -Jalon0/lat0[/horizon]/scale or -JAlon0/lat0[/horizon]/width (Lambert [E]).
                 lon0/lat0 specifies the projection center. horizon specifies  the  max  distance
                 from projection center (in degrees, <= 180, default 90). Give scale as 1:xxxx or
                 radius/lat, where radius is distance in UNIT from origin to the oblique latitude
                 lat.

          -Jelon0/lat0[/horizon]/scale or -JElon0/lat0[/horizon]/width (Azimuthal Equidistant).
                 lon0/lat0  specifies  the  projection center. horizon specifies the max distance
                 from projection center (in degrees, <= 180, default 180). Give scale  as  1:xxxx
                 or  radius/lat,  where  radius  is  distance  in UNIT from origin to the oblique
                 latitude lat.

          -Jflon0/lat0[/horizon]/scale or -JFlon0/lat0[/horizon]/width (Gnomonic).
                 lon0/lat0 specifies the projection center. horizon specifies  the  max  distance
                 from  projection  center (in degrees, < 90, default 60). Give scale as 1:xxxx or
                 radius/lat, where radius is distance in UNIT from origin to the oblique latitude
                 lat.

          -Jglon0/lat0[/horizon]/scale or -JGlon0/lat0[/horizon]/width (Orthographic).
                 lon0/lat0  specifies  the  projection center. horizon specifies the max distance
                 from projection center (in degrees, <= 90, default 90). Give scale as 1:xxxx  or
                 radius/lat, where radius is distance in UNIT from origin to the oblique latitude
                 lat.

          -Jglon0/lat0/altitude/azimuth/tilt/twist/Width/Height/scale                          or
          -JGlon0/lat0/altitude/azimuth/tilt/twist/Width/Height/width (General Perspective).
                 lon0/lat0 specifies the projection center. altitude is the height (in km) of the
                 viewpoint above local sea level. If altitude is less than 10,  then  it  is  the
                 distance  from  the  center  of  the  earth  to the viewpoint in earth radii. If
                 altitude has a suffix r then it is the radius from the center of  the  earth  in
                 kilometers. azimuth is measured to the east of north of view. tilt is the upward
                 tilt of the plane of projection. If tilt is  negative,  then  the  viewpoint  is
                 centered on the horizon. Further, specify the clockwise twist, Width, and Height
                 of the viewpoint in degrees. Give scale as 1:xxxx or radius/lat, where radius is
                 distance in UNIT from origin to the oblique latitude lat.

          -Jslon0/lat0[/horizon]/scale  or  -JSlon0/lat0[/horizon]/width  (General  Stereographic
          [C]).
                 lon0/lat0 specifies the projection center. horizon specifies  the  max  distance
                 from  projection  center  (in  degrees, < 180, default 90). Give scale as 1:xxxx
                 (true at pole) or lat0/1:xxxx (true at  standard  parallel  lat)  or  radius/lat
                 (radius in UNIT from origin to the oblique latitude lat). Note if 1:xxxx is used
                 then to specify horizon  you  must  also  specify  the  lat  as  +-90  to  avoid
                 ambiguity.

          MISCELLANEOUS PROJECTIONS:

          -Jh[lon0/]scale or -JH[lon0/]width (Hammer [E]).
                 Give  the  central  meridian  lon0 (optional) and scale along equator (1:xxxx or
                 UNIT/degree).

          -Ji[lon0/]scale or -JI[lon0/]width (Sinusoidal [E]).
                 Give the central meridian lon0 (optional) and scale  along  equator  (1:xxxx  or
                 UNIT/degree).

          -Jkf[lon0/]scale or -JKf[lon0/]width (Eckert IV) [E]).
                 Give  the  central  meridian  lon0 (optional) and scale along equator (1:xxxx or
                 UNIT/degree).

          -Jk[s][lon0/]scale or -JK[s][lon0/]width (Eckert VI) [E]).
                 Give the central meridian lon0 (optional) and scale  along  equator  (1:xxxx  or
                 UNIT/degree).

          -Jn[lon0/]scale or -JN[lon0/]width (Robinson).
                 Give  the  central  meridian  lon0 (optional) and scale along equator (1:xxxx or
                 UNIT/degree).

          -Jr[lon0/]scale -JR[lon0/]width (Winkel Tripel).
                 Give the central meridian lon0 (optional) and scale  along  equator  (1:xxxx  or
                 UNIT/degree).

          -Jv[lon0/]scale or -JV[lon0/]width (Van der Grinten).
                 Give  the  central  meridian  lon0 (optional) and scale along equator (1:xxxx or
                 UNIT/degree).

          -Jw[lon0/]scale or -JW[lon0/]width (Mollweide [E]).
                 Give the central meridian lon0 (optional) and scale  along  equator  (1:xxxx  or
                 UNIT/degree).

          NON-GEOGRAPHICAL PROJECTIONS:
          -Jp[a]scale[/origin][r|z] or -JP[a]width[/origin][r|z] (Polar coordinates (theta,r))

          Optionally  insert  a  after  -Jp  [  or  -JP]  for  azimuths  CW from North instead of
          directions CCW from East [Default]. Optionally append /origin in degrees to indicate an
          angular  offset [0]).  Finally, append r if r is elevations in degrees (requires s >= 0
          and n <= 90) or z if you want to annotate depth  rather  than  radius  [Default].  Give
          scale in UNIT/r-unit.
          -Jxx-scale[/y-scale] or -JXwidth[/height] (Linear, log, and power scaling)

          Give x-scale (1:xxxx or UNIT/x-unit) and/or y-scale (1:xxxx or UNIT/y-unit); or specify
          width and/or height in UNIT. y-scale=x-scale if  not  specified  separately  and  using
          1:xxxx  implies that x-unit and y-unit are in meters.  Use negative scale(s) to reverse
          the direction of an axis (e.g., to have y be positive down). Set height or width  to  0
          to  have it recomputed based on the implied scale of the other axis. Optionally, append
          to x-scale, y-scale, width or height one of the following:

              d      Data are geographical coordinates (in degrees).

              l      Take log10 of values before scaling.

              ppower Raise values to power before scaling.

              t      Input coordinates are time relative to TIME_EPOCH.

              T      Input coordinates are absolute time.

              For mixed axes with only one geographic axis you  may  need  to  set  -f  as  well.
              Default axis lengths (see gmt.conf) can be invoked using -JXh (for landscape); -JXv
              (for portrait) will swap the x- and y-axis  lengths.  The  default  unit  for  this
              installation is either cm or inch, as defined in the file share/gmt.conf.  However,
              you may change this by editing your gmt.conf file(s).

       When -J is used without any further arguments, or  just  with  the  projection  type,  the
       arguments  of  the  last  used  -J, or the last used -J with that projection type, will be
       used.

       -Jz|Zparameters
              Set z-axis scaling; same syntax as -Jx.

       -K     More PostScript code will be appended later [Default terminates the  plot  system].
              Required for all but the last plot command when building multi-layer plots.

       -O     Selects  Overlay  plot  mode [Default initializes a new plot system].  Required for
              all but the first plot command when building multi-layer plots.

       -P     Select “Portrait” plot orientation [Default is “Landscape”; see gmt.conf or  gmtset
              to      change      the      PS_PAGE_ORIENTATION      parameter,      or     supply
              --PS_PAGE_ORIENTATION=orientation on the command line].

       -Rxmin/xmax/ymin/ymax[+r][+uunit]
              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[:ss.xxx][W|E|S|N] format. Append +r if lower  left
              and upper right map coordinates are given instead of west/east/south/north. 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
              -Rcodex0/y0/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 x0/y0 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. When -R
              is used without any further arguments, the values from the last  use  of  -R  in  a
              previous  GMT  command  will be used.  For calendar time coordinates you may either
              give (a) relative time (relative to the selected TIME_EPOCH  and  in  the  selected
              TIME_UNIT;  append  t  to  -JX|x),  or (b) 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
              exactly as indicated (however, input, output and plot formats are customizable; see
              gmt.conf).   You  can  also use Cartesian projected coordinates compatible with the
              chosen  projection.   Append  the  length  unit  via  the   +u   modifier,   (e.g.,
              -R-200/200/-300/300+uk  for  a  400  by  600  km  rectangular  area centered on the
              projection center (0,  0).  These  coordinates  are  internally  converted  to  the
              corresponding  geographic  (longitude, latitude) coordinates for the lower left and
              upper right corners. This form is convenient when you  want  to  specify  a  region
              directly in the projected units (e.g., UTM meters).

       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.

       -U[[just]/dx/dy/][c|label]
              Draw Unix System time stamp on plot. By adding [just]/dx/dy/, the user may  specify
              the justification of the stamp and where the stamp should fall on the page relative
              to lower left corner of the plot.  For example, BL/0/0 will align  the  lower  left
              corner  of  the time stamp with the lower left corner of the plot [LL]. Optionally,
              append a label, or c (which will plot the  command  string.).  The  GMT  parameters
              MAP_LOGO,  MAP_LOGO_POS,  and  FORMAT_TIME_STAMP can affect the appearance; see the
              gmt.conf man page for details. The time string will be in the  locale  set  by  the
              environment variable TZ (generally local time).

       -V[level]
              Select  verbose  mode,  which will send progress reports to stderr.  Choose among 6
              levels of verbosity; each level adds more messages: q - Complete silence, not  even
              fatal  error messages are produced.  n - Normal verbosity: produce only fatal error
              messages.  c - Produce also compatibility warnings (same as when -V is omitted).  v
              -  Produce also warnings and progress messages (same as -V only).  l - Produce also
              detailed progress messages.  d - Produce also debugging messages.

       -X[a|c|f|r][x-shift[u]]

       -Y[a|c|f|r][y-shift[u]]
              Shift  plot  origin  relative  to  the  current  origin  by  (x-shift,y-shift)  and
              optionally  append  the  length  unit  (c, i, or p). You can prepend a to shift the
              origin back to the original position after plotting, prepend c to center  the  plot
              on  the  center  of the paper (optionally add shift), prepend f to shift the origin
              relative to the fixed lower left corner of the page, or prepend r [Default] to move
              the  origin  relative  to  its  current  location.  If  -O is used then the default
              (x-shift,y-shift) is (r0), otherwise it is (r1i). When -X or -Y  are  used  without
              any  further  arguments,  the values from the last use of that option in a previous
              GMT command will be used.

       -a[col=]name[]
              Control how aspatial data are handled in GMT  during  input  and  output.   Reading
              OGR/GMT-formatted files: To assign certain aspatial data items to GMT data columns,
              give one or more comma-separated associations col=name, where name is the  name  of
              an  aspatial  attribute  field  in a OGR/GMT file and whose value we wish to use as
              data input for column col. In addition, to assign an aspatial value  to  non-column
              data,  you  may specify col as D for distance, G for fill, I for ID, L for label, T
              for text, W for pen, and Z for value [e.g., used to look up color via a  CPT].   If
              you  skip  the  leading  “col=”  in  the argument then we supply (and automatically
              increment) a column value starting at 2.  Writing OGR/GMT-formatted files: To write
              OGR/GMT-formatted   files,   give   one   or   more   comma-separated  associations
              col=name[:type], with an optional data type  from  DOUBLE,  FLOAT,  INTEGER,  CHAR,
              STRING, DATETIME, or LOGICAL [DOUBLE]. To extract information from GMT multisegment
              headers encoded in the -Ddistance, -Gfill, -IID, -Llabel, -Ttext, -Wpen, or -Zvalue
              settings,  specify  COL  as  D,  G, I, L, T, W or Z, respectively; type will be set
              automatically. Finally, you must append +ggeometry, where geometry is either POINT,
              LINE,  or  POLY.  Optionally,  prepend M for multi-versions of these geometries. To
              force the clipping of features crossing the Dateline, use  upper-case  +G  instead.
              See GMT Appendix Q for details of the OGR/GMT file format.

       -bi[ncols][type][w][+L|+B]
              Select  native  binary  input.  Here,  ncols is the number of data columns of given
              type, which must be one of c (int8_t, aka char), u (uint8_t, aka unsigned char),  h
              (int16_t, 2-byte signed int), H (uint16_t, 2-byte unsigned int), i (int32_t, 4-byte
              signed int), I ((capital i) uint32_t, 4-byte unsigned  int),  l  ((lower  case  el)
              int64_t,  8-byte  signed  int),  L  (uint64_t,  8-byte  unsigned  int),  f  (4-byte
              single-precision float), and d (8-byte double-precision float). In addition, use  x
              to  skip  ncols bytes anywhere in the record.  For records with mixed types, simply
              append additional comma-separated combinations of ncolst. Append w to any  item  to
              force  byte-swapping.  Alternatively,  append +L|B to indicate that the entire data
              file should be read as little- or big-endian, respectively. The  cumulative  number
              of  ncols  may  exceed  the columns actually needed by the program. If ncols is not
              specified we assume that type applies to all columns and that ncols is  implied  by
              the  expectation  of  the  program.  If  the input file is netCDF, no -b is needed;
              simply append ?var1/var2/ to the filename to specify the variables to be read.

       -bo[ncols][type][w][+L|+B]
              Select native binary output. Here, ncols is the actual number of  data  columns  of
              type  t, which must be one of c, u, h, H, i, I (capital i), l (lower case elle), L,
              f,  and  d  (see  -bi).   For  a  mixed-type  output  record,   append   additional
              comma-separated   combinations   of  ncols/t.   Append  w  to  any  item  to  force
              byte-swapping or +L|B for byte-swapping of the  entire  record.  If  ncols  is  not
              specified  we assume that t applies to all columns and that ncols is implied by the
              default output of the program. Note: NetCDF file output is not supported.

       -d[i|o]nodata
              Control how user-coded missing data values are translated to official NaN values in
              GMT.   For  input data we replace any value that equals nodata with NaN. For output
              data we replace any NaN with the chosen nodata value.   Use  -di  or  -do  to  only
              affect input or output.

       -dinodata
              Examine  all input columns and if any item equals nodata we interpret this value as
              a missing data item and substitute the value NaN.

       -donodata
              Examine all output columns and if any item equals NAN we  substitute  it  with  the
              chosen missing data value nodata.

       -e[~]”pattern” | -e[~]/regexp/[i]
              Only accept ASCII data records that contains the specified pattern.  To reverse the
              search, i.e., to only accept data record that do not contain the specified pattern,
              use  -e~.  Should  your  pattern  happen  to  start  with ~ you need to escape this
              character with a backslash [Default accepts all data records].  For  matching  data
              records  against  extended  regular  expressions enclose the expression in slashes.
              Append i for case-insensitive matching.  For a list of such patterns,  give  +ffile
              with  one  pattern  per line.  To give a single pattern starting with +f, escape it
              with a backslash.

       -f[i|o]colinfo
              Specify the data types of input and/or output columns (time or geographical  data).
              Specify  i  or  o  to  make  this apply only to input or output [Default applies to
              both]. Give one or more columns (or column ranges) separated by commas, or  use  -f
              multiple  times (column ranges must be given in the format start[:inc ]:stop, where
              inc defaults to 1  if  not  specified).   Append  T  (absolute  calendar  time),  t
              (relative  time in chosen TIME_UNIT since TIME_EPOCH), x (longitude), y (latitude),
              p[unit] (projected x,y map coordinates in given unit [meter]) or f (floating point)
              to  each  column  or  column  range  item.  Shorthands  -f[i|o]g means -f[i|o]0x,1y
              (geographic coordinates) and -f[i|o]c means -f[i|o]0-1f (Cartesian coordinates)

       -g[a]x|y|d|X|Y|D|[col]z[+|-]gap[u]
              Examine the spacing between consecutive data points in order to  impose  breaks  in
              the  line. Append x|X or y|Y to define a gap when there is a large enough change in
              the x or y coordinates, respectively, or d|D for distance gaps; use upper  case  to
              calculate  gaps  from  projected  coordinates. For gap-testing on other columns use
              [col]z; if col is not prepended the it defaults to 2 (i.e.,  3rd  column).   Append
              [+|-]gap  and  optionally  a  unit  u. Regarding optional signs: -ve means previous
              minus current column value must exceed gap to be a gap,  +ve  means  current  minus
              previous  column value must exceed gap, and no sign means the absolute value of the
              difference must exceed gap. For geographic data (x|y|d), the  unit  u  may  be  arc
              degree,  minute,  or  second,  or  meter [Default], foot, kilometer, Mile, nautical
              mile, or survey foot. For projected data (X|Y|D), choose from inch, centimeter,  or
              point  [Default  unit  set by PROJ_LENGTH_UNIT]. Note: For x|y|z with time data the
              unit is instead controlled by TIME_UNIT. Repeat  the  option  to  specify  multiple
              criteria,  of which any can be met to produce a line break. Issue an additional -ga
              to indicate that all criteria must be met instead.

       -h[i|o][n][+c][+d][+rremark][+ttitle]
              Primary input file(s) has header record(s). If used, the default number  of  header
              records is IO_N_HEADER_RECS [1]. Use -hi if only the primary input data should have
              header records [Default will write out header records if the input data have them].
              Blank  lines  and  lines  starting  with  #  are always skipped. For output you may
              request additional headers to be written via the option modifiers, and  use  +d  to
              remove  existing  header  records.  Append +c to issue a header comment with column
              names to the output [none].  Append +r to  add  a  remark  comment  to  the  output
              [none].   Append  +t  to  add a title comment to the output [none].  These optional
              strings may contain n to indicate line-breaks).  If used with native binary data we
              interpret n to instead mean the number of bytes to skip on input or pad on output.

       -icols[+l][+sscale][+ooffset][,]
              Select  specific  data  columns  for primary input, in arbitrary order. Columns not
              listed will be skipped. Give individual columns (or column  ranges  in  the  format
              start[:inc  ]:stop,  where  inc defaults to 1 if not specified) separated by commas
              [Default reads all columns in order, starting with the first column  (0)].  Columns
              may  be  repeated.   To each column, optionally add any of  the following: +l takes
              log10 of the input values first; +sscale, subsequently multiplies by a given  scale
              factor [1]; +ooffset, finally adds a given offset [0].

       -n[b|c|l|n][+a][+bBC][+c][+tthreshold]
              Select  grid  interpolation  mode by adding b for B-spline smoothing, c for bicubic
              interpolation, l for bilinear interpolation, or n for nearest-neighbor  value  (for
              example to plot categorical data). Optionally, append +a to switch off antialiasing
              (where supported). Append +bBC to override the boundary conditions used,  adding  g
              for  geographic,  p  for  periodic,  or  n for natural boundary conditions. For the
              latter two you may append x or y to specify just one direction, otherwise both  are
              assumed.  Append  +c  to clip the interpolated grid to input z-min/max [Default may
              exceed limits]. Append +tthreshold to control how close  to  nodes  with  NaNs  the
              interpolation  will go. A threshold of 1.0 requires all (4 or 16) nodes involved in
              interpolation to be non-NaN. 0.5 will interpolate about half  way  from  a  non-NaN
              value;  0.1  will  go about 90% of the way, etc.  [Default is bicubic interpolation
              with antialiasing and a threshold of 0.5, using geographic (if grid is known to  be
              geographic) or natural boundary conditions].

       -ocols[,…]
              Select  specific  data  columns for primary output, in arbitrary order. Columns not
              listed will be skipped. Give columns (or column ranges  in  the  format  start[:inc
              ]:stop, where inc defaults to 1 if not specified) separated by commas.  Columns may
              be repeated.  [Default writes all columns in order].

       -p[x|y|z]azim[/elev[/zlevel]][+wlon0/lat0[/z0]][+vx0/y0]
              Selects perspective view and sets  the  azimuth  and  elevation  of  the  viewpoint
              [180/90]. When -p is used in consort with -Jz or -JZ, a third value can be appended
              which indicates at which z-level all 2D material, like the plot frame,  is  plotted
              (in  perspective). [Default is at the bottom of the z-axis]. Use -px or -py to plot
              against the “wall” x = level or y = level (default  is  on  the  horizontal  plane,
              which  is  the  same  as using -pz). For frames used for animation, you may want to
              append + to fix the center of your data  domain  (or  specify  a  particular  world
              coordinate point with +wlon0/lat[/z]) which will project to the center of your page
              size (or specify the coordinates of the projected view point with +vx0/y0. When  -p
              is  used  without  any  further  arguments, the values from the last use of -p in a
              previous GMT command will  be  used.   Alternatively,  you  can  perform  a  simple
              rotation about the z-axis by just giving the rotation angle.  Optionally, use +v or
              +w to select another axis location than the plot origin.

       -r     Force  pixel  node  registration  [Default  is   gridline   registration].    (Node
              registrations  are  defined  in  Section  grid-registration  of  the  GMT Technical
              Reference and Cookbook.)

       -s[cols][a|r]
              Suppress output for records whose z-value equals NaN [Default outputs all records].
              Append  a  to  skip records where at least one field equal NaN. Append r to reverse
              the  suppression,  i.e.,  only  output  the  records  whose  z-value  equals   NaN.
              Alternatively,  indicate  a comma-separated list of all columns or column ranges to
              consider for this NaN test (Column ranges must be given in  the  format  start[:inc
              ]:stop, where inc defaults to 1 if not specified).

       -t[transp]
              Set  PDF  transparency level for an overlay, in 0-100 percent range. [Default is 0,
              i.e., opaque].

       -x[[-]n]
              Limit the  number  of  cores  to  be  used  in  any  OpenMP-enabled  multi-threaded
              algorithms.  By  default we try to use all available cores.  Append n to only use n
              cores (if too large it will be truncated to the maximum cores available).  Finally,
              give  a  negative n to select (all - n) cores (or at least 1 if n equals or exceeds
              all).  The -x option is only available to GMT modules compiled with OpenMP support.

       -:[i|o]
              Swap 1st and 2nd column on input and/or output [Default is no swapping].  Append  i
              to  select  input  only  or  o  to select output only. [Default affects both]. This
              option  is  typically  used  to  handle  (latitude,  longitude)  files;  see   also
              -icols[l][sscale][ooffset][,].

       -^ 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.

   Specifying Color
       color  The color of lines, areas and patterns can be specified by a valid color name, by a
              gray  shade  (in  the  range  0-255), by a decimal color code (r/g/b, each in range
              0-255; h-s-v, ranges 0-360, 0-1, 0-1; or c/m/y/k, each  in  range  0-1),  or  by  a
              hexadecimal  color  code  (#rrggbb,  as used in HTML). For PDF transparency, append
              @transparency in the 0-100 percent range [0 or  opaque].  See  gmtcolors  for  more
              information and a full list of color names.

   Specifying Fill
       fill   The  attribute  fill specifies the solid shade or solid color (see Specifying Color
              above) or the pattern  used  for  filling  polygons.   Patterns  are  specified  as
              ppattern,  where  pattern set the number of the built-in pattern (1-90) or the name
              of a raster image file. The optional +rdpi sets the resolution of the image [1200].
              For  1-bit  rasters:  use upper case P  for inverse video, or append +fcolor and/or
              +bcolor to specify fore- and background colors (use color =  -  for  transparency).
              See  GMT  Cookbook  &  Technical Reference Appendix E for information on individual
              built-in patterns.

   Specifying Fonts
       font   The attributes of text fonts as defined by font is a comma delimited list of  size,
              fonttype  and  fill,  each  of which is optional. size is the font size (usually in
              points) but c or i can be added to indicate other units. fonttype is the name (case
              sensitive!) of the font or its equivalent numerical ID (e.g., Helvetica-Bold or 1).
              fill specifies the gray shade, color or pattern of the text  (see  Specifying  Fill
              above).  Optionally,  you may append =pen to the fill value in order to draw a text
              outline. If you want to avoid that the outline partially obscures the text,  append
              append  =~pen  instead;  in  that  case  only  half the linewidth is plotted on the
              outside of the font only.  If an outline is requested, you may optionally skip  the
              text  fill  by setting it to -, in which case the full pen width is always used. If
              any of the font attributes is omitted their default or  previous  setting  will  be
              retained.

              The 35 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

   Specifying Pens
       pen    The  attributes of lines and symbol outlines as defined by pen is a comma-delimited
              list of width, color and style, each of which is optional. width can  be  indicated
              as a measure (in points (this is the default), centimeters, or inches) or as faint,
              default, thin[ner|nest], thick[er|est], fat[ter|test], or obese. color specifies  a
              gray  shade  or  color  (see  Specifying Color above). style can be any of ‘solid’,
              ‘dashed’ or ‘dotted’, or a custom combination of dashes ‘-‘ and dots ‘.’. If any of
              the  attributes  is omitted their default or previous setting will be retained. See
              GMT Cookbook & Technical Reference Specifying pen attributes for more information.

ASCII FORMAT PRECISION

       The ASCII output formats of numerical data are controlled by parameters in  your  gmt.conf
       file.  Longitude  and latitude are formatted according to FORMAT_GEO_OUT, absolute time is
       under the control of FORMAT_DATE_OUT and FORMAT_CLOCK_OUT, whereas general floating  point
       values are formatted according to FORMAT_FLOAT_OUT. Be aware that the format in effect can
       lead to loss of precision in ASCII output, which can lead to various problems  downstream.
       If  you find the output is not written with enough precision, consider switching to binary
       output (-bo if available) or specify more decimals using the FORMAT_FLOAT_OUT setting.

GRID FILE FORMATS

       By default GMT writes out grid as single precision floats  in  a  COARDS-complaint  netCDF
       file  format.   However, GMT is able to produce and read grid files in many other commonly
       used grid file formats and also facilitates so called  “packing”  of  grids,  writing  out
       floating  point data as 1- or 2-byte integers. To specify the precision, scale and offset,
       the user should  add  the  suffix  =id[/scale/offset[/nan]],  where  id  is  a  two-letter
       identifier  of the grid type and precision, and scale and offset are optional scale factor
       and offset to be applied to all grid values, and nan is the value used to indicate missing
       data.  In  case  the  two  characters  id  is  not provided, as in =/scale than a id=nf is
       assumed.  When reading grids, the format is generally automatically recognized from almost
       all  of  those  formats  that  GMT and GDAL combined offer. If not, the same suffix can be
       added to input grid file names.  See grdconvert and Section grid-file-format  of  the  GMT
       Technical Reference and Cookbook for more information.

       When  reading  a  netCDF file that contains multiple grids, GMT will read, by default, the
       first 2-dimensional grid that can find in that file. To  coax  GMT  into  reading  another
       multi-dimensional  variable  in  the  grid  file,  append ?varname to the file name, where
       varname is the name of the variable. Note that you may need to escape the special  meaning
       of  ?  in  your  shell  program  by  putting a backslash in front of it, or by placing the
       filename and suffix between quotes or double quotes. The ?varname suffix can also be  used
       for  output  grids  to  specify  a  variable  name  different  from  the default: “z”. See
       grdconvert and  Sections  modifiers-for-CF  and  grid-file-format  of  the  GMT  Technical
       Reference  and  Cookbook  for more information, particularly on how to read splices of 3-,
       4-, or 5-dimensional grids.

SEE ALSO

       Look up the individual man pages for more details and full syntax. Run gmt --help to  list
       all  GMT  programs  and  to  show  all installation directories. For an explanation of the
       various GMT settings in this man page (like FORMAT_FLOAT_OUT), see the man page of the GMT
       configuration  file  gmt.conf.  Information  is  also  available  on  the  GMT  home  page
       http://gmt.soest.hawaii.edu/

COPYRIGHT

       2018, P. Wessel, W. H. F. Smith, R. Scharroo, J. Luis, and F. Wobbe