Provided by: gmt-common_5.4.5+dfsg-1_all bug

NAME

       psternary - Plot data on ternary diagrams

SYNOPSIS

       psternary  [  table ] [ -JX *width*[unit] ] [  -Rwest/east/south/north[/zmin/zmax][+r] ] [
       -B[p|s]parameters ] [  -Ccpt ] [  -Gfill ] [  -K ] [  -La/b/c ] [  -M ] [  -N ] [  -O ]  [
       -P  ]  [   -S[symbol][size[u]  ]  [   -U[stamp]  ]  [   -V[level]  ]  [  -W[pen][attr] ] [
       -Xx_offset ] [  -Yy_offset ] [ -aflags ] [ -bibinary ]  [  -dinodata  ]  [  -eregexp  ]  [
       -fflags ] [ -ggaps ] [ -hheaders ] [ -iflags ] [ -pflags ] [ -ttransp ] [ -:[i|o] ]

       Note: No space is allowed between the option flag and the associated arguments.

DESCRIPTION

       psternary  reads  (a,b,c[,*z*])  records  from  files  [or  standard  input] and generates
       PostScript code that will plot symbols at those locations  on  a  ternary  diagram.  If  a
       symbol  is  selected  and  no  symbol size given, then psternary will interpret the fourth
       column of the input data as symbol size. Symbols whose size is <= 0  are  skipped.  If  no
       symbols  are  specified then the symbol code (see -S below) must be present as last column
       in the input.  The PostScript code is written to standard output.

OPTIONAL ARGUMENTS

       table  One or more ASCII (or binary, see -bi[ncols][type]) data table  file(s)  holding  a
              number  of  data  columns. If no tables are given then we read from standard input.
              Use -T to ignore all input files, including standard input (see below).

       -B[a|b|c]*args*
              For ternary diagrams the three sides are referred to as a, b, and c.  Thus, to give
              specific settings for one of these axis you must include the axis letter before the
              arguments.  If all axes have the same arguments then only give one  option  without
              the axis letter.  For more details, see the -B discussion in psbasemap.

       -Ccpt  Give  a  CPT  or specify -Ccolor1,color2[,color3,...]  to build a linear continuous
              CPT from those colors automatically.  In this case colorn can be a r/g/b triplet, a
              color name, or an HTML hexadecimal color (e.g. #aabbcc ).  If -S is set, let symbol
              fill color be determined by the z-value in the fourth column. Additional fields are
              shifted  over  by  one  column  (optional  size would be 5th rather than 4th field,
              etc.).

       -Gfill Select color or pattern for filling of symbols [Default is  no  fill].   Note  that
              psternary  will search for -G and -W strings in all the segment headers and let any
              values thus found over-ride the command line settings.

       -JXwidth [unit]
              The only valid projection is linear plot with specified ternary width.

       -K (more ...)
              Do not finalize the PostScript plot.

       -La/b/c
              Set the labels for the three diagram vertices [none].  These are placed a  distance
              of 3 times the MAP_LABEL_OFFSET setting from their respective corners.

       -M     Do  no  plotting.   Instead,  convert  the input (a,b,c[,*z*]) records to Cartesian
              (x,y,[,*z*]) records, where x, y are normalized coordinates on the triangle  (i.e.,
              0-1 in xand 0-sqrt(3)/2 in y).

       -N     Do  NOT  clip  symbols  that  fall  outside  map border [Default plots points whose
              coordinates are strictly inside the map border only].

       -O (more ...)
              Append to existing PostScript plot.

       -P (more ...)
              Select "Portrait" plot orientation.

       -Ramin/amax/bmin/bmax/cmin/cmax
              Give the min and max limits for each of the three axis a, b, and c.

       -S[symbol][size[u]]
              Plot symbols (including vectors, pie slices, fronts, decorated  or  quoted  lines).
              If  present,  size is symbol size in the unit set in gmt.conf (unless c, i, or p is
              appended). If the symbol code (see below) is not given it will  be  read  from  the
              last  column  in  the  input  data;  this cannot be used in conjunction with binary
              input.  Optionally, append c, i, or p to indicate that the size information in  the
              input   data  is  in  units  of  cm,  inch,  or  point,  respectively  [Default  is
              PROJ_LENGTH_UNIT]. Note: if you provide both size and symbol via the input file you
              must  use  PROJ_LENGTH_UNIT to indicate the unit used for the symbol size or append
              the units to the sizes in the file.  If symbol sizes are  expected  via  the  third
              data  column  then you may convert those values to suitable symbol sizes via the -i
              mechanism.

              The uppercase symbols A, C, D, G, H, I, N, S, T are normalized  to  have  the  same
              area  as a circle with diameter size, while the size of the corresponding lowercase
              symbols refers to the diameter of a circumscribed circle.

              You can change symbols by adding the required -S option to any of your multisegment
              headers.

              Choose between these symbol codes:

              -S-    x-dash (-). size is the length of a short horizontal (x-dir) line segment.

              -S+    plus (+). size is diameter of circumscribing circle.

              -Sa    star. size is diameter of circumscribing circle.

              -Sb[size[c|i|p|u]][b[base]]
                     Vertical  bar extending from base to y. size is bar width.  Append u if size
                     is in x-units [Default is plot-distance units].  By default,  base  =  ymin.
                     Append b[base] to change this value. If base is not appended then we read it
                     from the last input data column.

              -SB[size[c|i|p|u]][b[base]]
                     Horizontal bar extending from base to x. size is bar  width.   Append  u  if
                     size  is  in  y-units  [Default is plot-distance units].  By default, base =
                     xmin. Append b[base] to change this value. If base is not appended  then  we
                     read it from the last input data column.

              -Sc    circle. size is diameter of circle.

              -Sd    diamond. size is diameter of circumscribing circle.

              -Se    ellipse.   Direction   (in   degrees   counter-clockwise  from  horizontal),
                     major_axis, and minor_axis must be found in columns 3, 4, and 5.

              -SE    Same as -Se, except azimuth (in degrees  east  of  north)  should  be  given
                     instead  of direction. The azimuth will be mapped into an angle based on the
                     chosen map projection (-Se leaves the directions  unchanged.)   Furthermore,
                     the  axes  lengths  must  be  given in geographical instead of plot-distance
                     units. An exception occurs for a linear projection in which  we  assume  the
                     ellipse  axes  are  given  in the same units as -R.  For degenerate ellipses
                     (circles) with just the diameter given, use -SE-.  The diameter is  excepted
                     to be given in column 3.  Alternatively, append the desired diameter to -SE-
                     and this fixed diameter is used instead.  For allowable geographical  units,
                     see UNITS.

              -Sfgap[/size][+l|+r][+b+c+f+s+t][+ooffset][+p[pen]].
                     Draw a front. Supply distance gap between symbols and symbol size. If gap is
                     negative, it is interpreted to mean the number of symbols  along  the  front
                     instead.  If size is missing it is set to 30% of the gap, except when gap is
                     negative and size is thus required.  Append +l or +r to plot symbols on  the
                     left  or  right  side  of  the  front [Default is centered]. Append +type to
                     specify which symbol  to  plot:  box,  circle,  fault,  slip,  or  triangle.
                     [Default  is  fault].  Slip  means left-lateral or right-lateral strike-slip
                     arrows (centered is not an option). The +s modifier optionally  accepts  the
                     angle  used  to  draw  the  vector  [20].  Alternatively, use +S which draws
                     arcuate arrow heads.  Append +ooffset to offset the first  symbol  from  the
                     beginning  of  the front by that amount [0]. The chosen symbol is drawn with
                     the same pen as set for the line (i.e., via -W).  The use an alternate  pen,
                     append  +ppen.   To  skip  the  outline,  just use +p.  Note: By placing -Sf
                     options in  the  segment  header  you  can  change  the  front  types  on  a
                     segment-by-segment basis.

              -Sg    octagon. size is diameter of circumscribing circle.

              -Sh    hexagon. size is diameter of circumscribing circle.

              -Si    inverted triangle. size is diameter of circumscribing circle.

              -Sj    Rotated rectangle. Direction (in degrees counter-clockwise from horizontal),
                     x-dimension, and y-dimension must be found in columns 3, 4, and 5.

              -SJ    Same as -Sj, except azimuth (in degrees  east  of  north)  should  be  given
                     instead  of direction. The azimuth will be mapped into an angle based on the
                     chosen map projection (-Sj leaves the  directions  unchanged.)  Furthermore,
                     the dimensions must be given in geographical instead of plot-distance units.
                     For a degenerate rectangle (square) with one dimension given, use -SJ-.  The
                     dimension  is  excepted  to be given in column 3.  Alternatively, append the
                     dimension diameter to -SJ- and this fixed dimension  is  used  instead.   An
                     exception  occurs  for a linear projection in which we assume the dimensions
                     are given in the same units as -R.  For allowable  geographical  units,  see
                     UNITS.

              -Sk    kustom  symbol.  Append  name/size,  and  we will look for a definition file
                     called name.def in (1) the current directory or (2)  in  ~/.gmt  or  (3)  in
                     $GMT_SHAREDIR/custom.  The  symbol as defined in that file is of size 1.0 by
                     default; the appended size will scale  symbol  accordingly.  Users  may  add
                     their own custom *.def files; see CUSTOM SYMBOLS below.

              -Sl    letter  or  text  string  (less  than 256 characters). Give size, and append
                     +tstring after the  size.  Note  that  the  size  is  only  approximate;  no
                     individual  scaling  is  done  for  different characters. Remember to escape
                     special characters like *. Optionally, you may append  +ffont  to  select  a
                     particular  font  [Default  is  FONT_ANNOT_PRIMARY]  and +jjustify to change
                     justification [CM].

              -Sm    math angle arc, optionally with one or two arrow heads [Default is no  arrow
                     heads].  The  size is the length of the vector head. Arc width is set by -W.
                     The radius of the  arc  and  its  start  and  stop  directions  (in  degrees
                     counter-clockwise  from horizontal) must be given in columns 3-5. See VECTOR
                     ATTRIBUTES for specifying other attributes.

              -SM    Same as -Sm but switches to straight  angle  symbol  if  angles  subtend  90
                     degrees exactly.

              -Sn    pentagon. size is diameter of circumscribing circle.

              -Sp    point. No size needs to be specified (1 pixel is used).

              -Sq    quoted   line,  i.e.,  lines  with  annotations  such  as  contours.  Append
                     [d|D|f|l|L|n|N|s|S|x|X]info[:labelinfo].  The required argument controls the
                     placement  of  labels  along  the quoted lines. Choose among six controlling
                     algorithms:

                        ddist[c|i|p] or Ddist[d|e|f|k|m|M|n|s]
                               For lower case d, give distances between labels  on  the  plot  in
                               your  preferred  measurement unit c (cm), i (inch), or p (points),
                               while for upper case D, specify distances in map units and  append
                               the  unit;  choose  among  e  (m),  f  (foot), k (km), M (mile), n
                               (nautical mile) or u (US survey foot), and d (arc degree), m  (arc
                               minute), or s (arc second).  [Default is 10c or 4i]. As an option,
                               you can append /fraction which is used to  place  the  very  first
                               label  for each contour when the cumulative along-contour distance
                               equals fraction * dist [0.25].

                        fffile.d
                               Reads the ASCII file ffile.d and places labels at locations in the
                               file  that  matches  locations  along  the  quoted  lines. Inexact
                               matches and points outside the region are skipped.

                        l|Lline1[,line2,...]
                               Give  the  coordinates  of  the  end  points  for  one   or   more
                               comma-separated  straight  line  segments.   Labels will be placed
                               where these lines intersect the quoted lines.  The format of  each
                               line specification is start_lon/start_lat/stop_lon/stop_lat.  Both
                               start_lon/start_lat and stop_lon/stop_lat can  be  replaced  by  a
                               2-character  key  that  uses  the justification format employed in
                               pstext to indicate a point on the frame  or  center  of  the  map,
                               given as [LCR][BMT].  L will interpret the point pairs as defining
                               great circles [Default is straight line].

                        n|Nn_label
                               Specifies the number of equidistant labels for quoted  lines  [1].
                               Upper  case  N  starts  labeling  exactly at the start of the line
                               [Default centers them along the line]. N-1  places  one  justified
                               label at start, while N+1 places one justified label at the end of
                               quoted lines. Optionally, append /min_dist[c|i|p] to enforce  that
                               a   minimum  distance  separation  between  successive  labels  is
                               enforced.

                        s|Sn_label
                               Same as n|Nn_label but implies that the input data are first to be
                               converted into a series of 2-point line segments before plotting.

                        x|Xxfile.d
                               Reads  the  multisegment  file  xfile.d  and  places labels at the
                               intersections between the quoted lines and the lines  in  xfile.d.
                               X  will  resample  the  lines  first  along great-circle arcs.  In
                               addition, you may  optionally  append  +rradius[c|i|p]  to  set  a
                               minimum label separation in the x-y plane [no limitation].

                        The optional labelinfo controls the specifics of the label formatting and
                        consists of a concatenated string made up of any of the following control
                        arguments:

                        +aangle
                               For  annotations at a fixed angle, +an for line-normal, or +ap for
                               line-parallel [Default].

                        +cdx[/dy]
                               Sets the clearance between label and  optional  text  box.  Append
                               c|i|p  to  specify  the  unit or % to indicate a percentage of the
                               label font size [15%].

                        +d     Turns on  debug  which  will  draw  helper  points  and  lines  to
                               illustrate the workings of the quoted line setup.

                        +e     Delay  the plotting of the text. This is used to build a clip path
                               based on the text, then lay down other overlays  while  that  clip
                               path  is in effect, then turning of clipping with psclip -Cs which
                               finally plots the original text.

                        +ffont Sets the desired font [Default FONT_ANNOT_PRIMARY  with  its  size
                               changed to 9p].

                        +g[color]
                               Selects  opaque  text  boxes  [Default is transparent]; optionally
                               specify the color [Default is PS_PAGE_COLOR].

                        +jjust Sets label justification [Default is MC]. Ignored when  -SqN|n+|-1
                               is used.

                        +llabel
                               Sets the constant label text.

                        +Lflag Sets the label text according to the specified flag:

                               +Lh Take the label from the current segment header (first scan for
                               an embedded -Llabel option, if not use the  first  word  following
                               the  segment flag). For multiple-word labels, enclose entire label
                               in double quotes.  +Ld Take the Cartesian plot distances along the
                               line   as  the  label;  append  c|i|p  as  the  unit  [Default  is
                               PROJ_LENGTH_UNIT].  +LD Calculate  actual  map  distances;  append
                               d|e|f|k|n|M|n|s  as  the  unit [Default is d(egrees), unless label
                               placement was based on map distances along the lines in which case
                               we use the same unit specified for that algorithm]. Requires a map
                               projection to be used.  +Lf Use text after the 2nd column  in  the
                               fixed  label  location file as the label. Requires the fixed label
                               location setting.  +Lx As +Lh but use the headers in  the  xfile.d
                               instead.  Requires the crossing file option.

                        +ndx[/dy]
                               Nudges  the  placement  of  labels by the specified amount (append
                               c|i|p to specify the units).  Increments  are  considered  in  the
                               coordinate  system  defined by the orientation of the line; use +N
                               to force  increments  in  the  plot  x/y  coordinates  system  [no
                               nudging]. Not allowed with +v.

                        +o     Selects  rounded  rectangular  text  box [Default is rectangular].
                               Not applicable for curved text  (+v)  and  only  makes  sense  for
                               opaque text boxes.

                        +p[pen]
                               Draws   the  outline  of  text  boxes  [Default  is  no  outline];
                               optionally specify pen for outline  [Default  is  width  =  0.25p,
                               color = black, style = solid].

                        +rmin_rad
                               Will not place labels where the line's radius of curvature is less
                               than min_rad [Default is 0].

                        +t[file]
                               Saves line label x, y, and text to file [Line_labels.txt].  Use +T
                               to save x, y, angle, text instead.

                        +uunit Appends  unit  to  all  line labels. If unit starts with a leading
                               hyphen (-) then there will be no space between label value and the
                               unit. [Default is no unit].

                        +v     Specifies  curved  labels  following the path [Default is straight
                               labels].

                        +w     Specifies how many (x,y) points will be  used  to  estimate  label
                               angles [Default is 10].

                        +x[first,last]
                               Append  the  suffices  first and last to the corresponding labels.
                               This modifier is only available when -SqN2 is in effect.  Used  to
                               annotate  the  start  and  end  of a line (e.g., a cross-section),
                               append two text strings separated by comma [Default  just  adds  a
                               prime to the second label].

                        +=prefix
                               Prepends  prefix  to  all  line  labels.  If  prefix starts with a
                               leading hyphen (-) then there will be no space between label value
                               and the prefix. [Default is no prefix].

                     Note: By placing -Sq options in the segment header you can change the quoted
                     text attributes on a segment-by-segment basis.

              -Sr    rectangle. No size needs to be specified, but the x- and  y-dimensions  must
                     be found in columns 3 and 4.

              -SR    Rounded   rectangle.  No  size  needs  to  be  specified,  but  the  x-  and
                     y-dimensions and corner radius must be found in columns 3, 4, and 5.

              -Ss    square. size is diameter of circumscribing circle.

              -St    triangle. size is diameter of circumscribing circle.

              -Sv    vector. Direction (in degrees counter-clockwise from horizontal) and  length
                     must  be  found  in  columns  3  and  4,  and  size, if not specified on the
                     command-line, should be  present in column 5.  The size is the length of the
                     vector  head.  Vector  width  is  set  by  -W.   See  VECTOR  ATTRIBUTES for
                     specifying other attributes.

              -SV    Same as -Sv, except azimuth (in degrees  east  of  north)  should  be  given
                     instead  of direction. The azimuth will be mapped into an angle based on the
                     chosen map projection (-Sv leaves  the  directions  unchanged.)  See  VECTOR
                     ATTRIBUTES for specifying other attributes.

              -Sw    pie  wedge.  Start  and  stop  directions (in degrees counter-clockwise from
                     horizontal) for pie slice must be found in columns 3 and 4.   Append  +a  to
                     just draw the arc line or +r to just draw the radial lines.

              -SW    Same  as  -Sw,  except  azimuths  (in degrees east of north) should be given
                     instead of the two directions. The azimuths will be mapped into angles based
                     on  the  chosen  map  projection (-Sw leaves the directions unchanged.)  For
                     geo-wedges, specify size as a radial geographical distance.   For  allowable
                     geographical units, see UNITS.  Append +a to just draw the arc or +r to just
                     draw the radial lines.

              -Sx    cross (x). size is diameter of circumscribing circle.

              -Sy    y-dash (|). size is the length of a short vertical (y-dir) line segment.

              -S=    geovector. Azimuth (in degrees east from north) and geographical length must
                     be  found  in  columns  3  and 4. The size is the length of the vector head.
                     Vector width is set by -W. See VECTOR ATTRIBUTES for specifying  attributes.
                     Note:  Geovector  stems  are  drawn  as  thin  filled polygons and hence pen
                     attributes  like  dashed  and  dotted  are  not  available.   For  allowable
                     geographical units, see UNITS.

              -S~    decorated    line,   i.e.,   lines   with   symbols   along   them.   Append
                     [d|D|f|l|L|n|N|s|S|x|X]info[:symbolinfo].  The  required  argument  controls
                     the  placement  of  symbols  along  the  decorated  lines.  Choose among six
                     controlling algorithms:

                        ddist[c|i|p] or Ddist[d|e|f|k|m|M|n|s]
                               For lower case d, give distances between symbols on  the  plot  in
                               your  preferred  measurement unit c (cm), i (inch), or p (points),
                               while for upper case D, specify distances in map units and  append
                               the  unit;  choose  among  e  (m),  f  (foot), k (km), M (mile), n
                               (nautical mile) or u (US survey foot), and d (arc degree), m  (arc
                               minute), or s (arc second).  [Default is 10c or 4i]. As an option,
                               you can append /fraction which is used to  place  the  very  first
                               symbol  for  each  line  when  the  cumulative along-line distance
                               equals fraction * dist [0.25].

                        fffile.d
                               Reads the ASCII file ffile.d and places symbols  at  locations  in
                               the file that matches locations along the decorated lines. Inexact
                               matches and points outside the region are skipped.

                        l|Lline1[,line2,...]
                               Give  the  coordinates  of  the  end  points  for  one   or   more
                               comma-separated  straight  line  segments.  Symbols will be placed
                               where these lines intersect the decorated lines.   The  format  of
                               each  line specification is start_lon/start_lat/stop_lon/stop_lat.
                               Both start_lon/start_lat and stop_lon/stop_lat can be replaced  by
                               a  2-character  key that uses the justification format employed in
                               pstext to indicate a point on the frame  or  center  of  the  map,
                               given as [LCR][BMT].  L will interpret the point pairs as defining
                               great circles [Default is straight line].

                        n|Nn_symbol
                               Specifies the number of equidistant symbols  for  decorated  lines
                               [1].  Upper  case N starts placing symbols exactly at the start of
                               the line [Default centers them along the  line].  N-1  places  one
                               symbol  at  start,  while  N+1  places  one  symbol  at the end of
                               decorated lines. Optionally, append  /min_dist[c|i|p]  to  enforce
                               that  a  minimum distance separation between successive symbols is
                               enforced.

                        s|Sn_symbol
                               Same as n|Nn_symbol but implies that the input data are  first  to
                               be  converted  into  a  series  of  2-point  line  segments before
                               plotting.

                        x|Xxfile.d
                               Reads the multisegment file xfile.d  and  places  symbols  at  the
                               intersections  between  the  decorated  lines  and  the  lines  in
                               xfile.d.  X will resample the lines first along great-circle arcs.

                        The optional symbolinfo controls the specifics of  the  symbol  selection
                        and  formatting  and  consists of a concatenated string made up of any of
                        the following control arguments:

                        +aangle
                               For symbols at a fixed angle, +an  for  line-normal,  or  +ap  for
                               line-parallel [Default].

                        +d     Turns  on  debug  which  will  draw  helper  points  and  lines to
                               illustrate the workings of the decorated line setup.

                        +g[fill]
                               Sets the symbol fill [no fill].

                        +ndx[/dy]
                               Nudges the placement of symbols by the  specified  amount  (append
                               c|i|p  to  specify  the  units).  Increments are considered in the
                               coordinate system defined by the orientation of the line;  use  +N
                               to  force  increments  in  the  plot  x/y  coordinates  system [no
                               nudging].

                        +p[pen]
                               Draws the outline of symbols [Default is no  outline];  optionally
                               specify  pen for outline [Default is width = 0.25p, color = black,
                               style = solid].

                        +s<symbol><size>
                               Specifies the code and size of the decorative symbol.

                        +w     Specifies how many (x,y) points will be used  to  estimate  symbol
                               angles [Default is 10].

                     Note:  By  placing  -S~  options  in  the  segment header you can change the
                     decorated lines on a segment-by-segment basis.

       -U[[just]/dx/dy/][c|label] (more ...)
              Draw GMT time stamp logo on plot.

       -V[level] (more ...)
              Select verbosity level [c].

       -W[pen][attr] (more ...)
              Set pen attributes for the outline of symbols.

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

       -Y[a|c|f|r][y-shift[u]] (more ...)
              Shift plot origin.

       -bi[ncols][t] (more ...)
              Select native binary input. [Default is the required number of  columns  given  the
              chosen settings].

       -acol=name[...] (more ...)
              Set aspatial column associations col=name.

       -dinodata (more ...)
              Replace input columns that equal nodata with NaN.

       -e[~]"pattern" | -e[~]/regexp/[i] (more ...)
              Only accept data records that match the given pattern.

       -f[i|o]colinfo (more ...)
              Specify data types of input and/or output columns.

       -g[a]x|y|d|X|Y|D|[col]z[+|-]gap[u] (more ...)
              Determine data gaps and line breaks. The -g option is ignored if -S is set.

       -h[i|o][n][+c][+d][+rremark][+rtitle] (more ...)
              Skip or produce header record(s).

       -icols[+l][+sscale][+ooffset][,...] (more ...)
              Select input columns and transformations (0 is first column).

       -:[i|o] (more ...)
              Swap 1st and 2nd column on input and/or output.

       -p[x|y|z]azim[/elev[/zlevel]][+wlon0/lat0[/z0]][+vx0/y0] (more ...)
              Select perspective view.

       -t[transp] (more ...)
              Set PDF transparency level in percent.

       -^ or just -
              Print a short message about the syntax of the command, then exits (NOTE: on Windows
              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.

UNITS

       For map distance unit, append unit d for arc degree, m for  arc  minute,  and  s  for  arc
       second, or e for meter [Default], f for foot, k for km, M for statute mile, n for nautical
       mile, and u for US survey foot. By default we compute such  distances  using  a  spherical
       approximation  with  great circles. Prepend - to a distance (or the unit is no distance is
       given) to perform "Flat Earth" calculations (quicker but less accurate) or  prepend  +  to
       perform exact geodesic calculations (slower but more accurate).

VECTOR ATTRIBUTES

       Several modifiers may be appended to the vector-producing options to specify the placement
       of vector heads, their shapes, and the justification of the vector. Below, left and  right
       refers to the side of the vector line when viewed from the start point to the end point of
       the segment:
          +aangle sets the angle of the vector head apex [30].

          +b places a vector head at the beginning of the vector path [none].  Optionally, append
          t  for  a terminal line, c for a circle, a for arrow [Default], i for tail, A for plain
          arrow, and I for plain tail.  Further append l|r to only draw the left or right side of
          this head [both sides].

          +e places a vector head at the end of the vector path [none].  Optionally, append t for
          a terminal line, c for a circle, a for arrow [Default], i for tail, A for plain  arrow,
          and  I  for plain tail.  Further append l|r to only draw the left or right side of this
          head [both sides].

          +g-|fill turns off vector head fill (if -) or sets the vector head fill  [Default  fill
          is used, which may be no fill].

          +hshape  sets  the  shape  of  the  vector  head (range -2/2). Default is controlled by
          MAP_VECTOR_SHAPE [0].

          +l draws half-arrows, using only the left side of specified heads [both sides].

          +m places a vector head at the mid-point the vector path [none].  Append  f  or  r  for
          forward  or  reverse  direction  of  the  vector [forward].  Optionally, append t for a
          terminal line, c for a circle, or a for arrow head [Default].  Further  append  l|r  to
          only draw the left or right side of this head [both sides].  Cannot be combined with +b
          or +e.

          +nnorm scales down vector attributes (pen thickness, head size) with decreasing length,
          where vectors shorter than norm will have their attributes scaled by length/norm [arrow
          attributes remains invariant to length].

          +oplon/plat specifies the oblique pole for the great or small circles.  Only needed for
          great circles if +q is given.

          +p[-][pen] sets the vector pen attributes. If pen has a leading - then the head outline
          is not drawn. [Default pen is used, and head outline is drawn]

          +q means the input angle, length data instead represent  the  start  and  stop  opening
          angles of the arc segment relative to the given point.

          +r draws half-arrows, using only the right side of specified heads [both sides].

          +t[b|e]trim will shift the beginning or end point (or both) along the vector segment by
          the given trim; append suitable unit. If the modifiers b|e are not used then  trim  may
          be  two  values  separated by a slash, which is used to specify different trims for the
          two ends.  Positive trims will shorted the vector while negative trims will lengthen it
          [no trim].

       In addition, all but circular vectors may take these modifiers:
          +jjust  determines how the input x,y point relates to the vector. Choose from beginning
          [default], end, or center.

          +s means the input angle, length are instead the x, y coordinates  of  the  vector  end
          point.

       Finally, Cartesian vectors may take these modifiers:
          +zscale[unit]  expects  input  dx,dy vector components and uses the scale to convert to
          polar coordinates with length in given unit.

EXAMPLES

       To plot circles (diameter = 0.1 cm) on a 6-inch-wide  ternary  diagram  at  the  positions
       listed  in the file ternary.txt, with default annotations and gridline spacings, using the
       specified labeling, tru

              gmt psternary ternary.txt -R0/100/0/100/0/100 -JX6i -P -Xc -Baafg+l"Water component"+u" %" \
              -Bbafg+l"Air component"+u" %" -Bcagf+l"Limestone component"+u" %" \
              -B+givory+t"Example data from MATLAB Central" -Sc0.1c -Ct.cpt -Y2i -LWater/Air/Limestone > map.ps

SEE ALSO

       gmt, gmt.conf, gmtcolors, psbasemap, psxy, psxyz

COPYRIGHT

       2019, P. Wessel, W. H. F. Smith, R. Scharroo, J. Luis, and F. Wobbe