Provided by: gmt-common_5.4.5+dfsg-2_all bug


       makecpt - Make GMT color palette tables


       makecpt  [   -A[+]transparency  ]  [   -Ccpt ] [  -D[i|o] ] [  -E[nlevels] ] [  -F[R|r|h|c
       ][+c]]  [   -Gzlo/zhi  ]  [   -I[c][z]  ]  [   -M   ]   [    -N   ]   [    -Q[i|o]   ]   [
       -Tz_min/z_max[/z_inc[+]] | -Tztable | -Tz1,z2,...,zn ] [  -V[level] ] [  -W[w] ] [  -Z ] [
       -bibinary ] [ -dinodata ] [ -iflags ]

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


       makecpt is a utility that will help you make  static  color  palette  tables  (CPTs).  You
       define  an  equidistant  set  of  contour  intervals or pass your own z-table or list, and
       create a new CPT based on an existing master (dynamic)  CPT.  The  resulting  CPT  can  be
       reversed  relative  to  the master cpt, and can be made continuous or discrete.  For color
       tables     beyond     the      standard      GMT      offerings,      visit      cpt-city:

       The  CPT  includes  three  additional  colors  beyond the range of z-values. These are the
       background color (B) assigned to values lower than  the  lowest  z-value,  the  foreground
       color  (F)  assigned  to  values  higher  than  the highest z-value, and the NaN color (N)
       painted wherever values are undefined.

       If the master CPT includes B, F, and N entries, these will be copied into the  new  master
       file.  If  not,  the parameters COLOR_BACKGROUND, COLOR_FOREGROUND, and COLOR_NAN from the
       gmt.conf file or the command line will be used. This default  behavior  can  be  overruled
       using the options -D, -M or -N.

       The  color  model (RGB, HSV or CMYK) of the palette created by makecpt will be the same as
       specified in the header of the master CPT. When there  is  no  COLOR_MODEL  entry  in  the
       master  CPT, the COLOR_MODEL specified in the gmt.conf file or on the command line will be




              Sets a constant level of transparency (0-100) for all color slices.  Prepend  +  to
              also  affect  the fore-, back-, and nan-colors [Default is no transparency, i.e., 0

       -Ccpt  Selects the master color table CPT to use in the interpolation.  Choose  among  the
              built-in  tables (type makecpt to see the list) or give the name of an existing CPT
              [Default  gives   a   rainbow   CPT].    Yet   another   option   is   to   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 ).

              Select  the  back- and foreground colors to match the colors for lowest and highest
              z-values in the output CPT [Default uses the colors specified in the  master  file,
              or   those  defined  by  the  parameters  COLOR_BACKGROUND,  COLOR_FOREGROUND,  and
              COLOR_NAN]. Append i to match the colors for the lowest and highest values  in  the
              input (instead of the output) CPT.

              Implies  reading data table(s) from given command-line files or standard input.  We
              use the last data column to determine the data range;  use  -i  to  select  another
              column,  and use -bi if your data table is native binary.  This z-range information
              is used instead of providing the -T option.  We create  a  linear  color  table  by
              dividing the table data z-range into nlevels equidistant slices.  If nlevels is not
              given it defaults to the number of levels in the chosen CPT.

              Force output CPT to written with r/g/b codes, gray-scale values or color  name  (R,
              default)  or  r/g/b  codes  only  (r),  or  h-s-v  codes (h), or c/m/y/k codes (c).
              Optionally or alternatively, append +c to write discrete  palettes  in  categorical

              Truncate  the  incoming  CPT so that the lowest and highest z-levels are to zlo and
              zhi.  If one of these equal NaN then we leave that  end  of  the  CPT  alone.   The
              truncation takes place before any resampling. See also manipulating_CPTs

              Append  c  [Default]  to  reverse the sense of color progression in the master CPT.
              Also exchanges the foreground and background colors, including those  specified  by
              the parameters COLOR_BACKGROUND and COLOR_FOREGROUND.  Append z to reverse the sign
              of z-values in the color table.  Note  that  this  change  of  z-direction  happens
              before  -G and -T values are used so the latter much be compatible with the changed
              z-range.  See also manipulating_CPTs

       -M     Overrule background, foreground, and NaN colors specified in the  master  CPT  with
              the  values  of  the  parameters  COLOR_BACKGROUND, COLOR_FOREGROUND, and COLOR_NAN
              specified in the gmt.conf file or on the command line. When combined with -D,  only
              COLOR_NAN is considered.

       -N     Do  not  write  out  the background, foreground, and NaN-color fields [Default will
              write them].

              Selects a logarithmic interpolation scheme [Default is linear].  -Qi expects  input
              z-values  to  be  log10(z),  assigns  colors, and writes out z [Default]. -Qo takes
              log10(z) first, assigns colors, and writes out z.

       -Tz_min/z_max[/z_inc[+]] | -Tztable | -Tz1,z2,...,zn
              Defines the range of the new CPT by giving  the  lowest  and  highest  z-value  and
              interval.   Append  /z_inc  to  sample  the input CPT discretely at intervals z_inc
              between z_min and z_max; append a trailing + to interpret z_inc as  the  number  of
              desired  intervals  instead.  Alternatively, give the name of a ASCII file that has
              one z-value per record, or provide a list of comma-separated z-values instead.   If
              -T is not given, the existing range in the master CPT will be used intact.

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

       -W[w]  Do not interpolate the input color table but pick the output colors starting at the
              beginning of the color table, until colors for all intervals are assigned. This  is
              particularly   useful   in   combination  with  a  categorical  color  table,  like
              "categorical". Cannot be used in combination with -Z.  Alternatively,  use  -Ww  to
              produce a wrapped (cyclic) color table that endlessly repeats its range.

       -Z     Creates  a continuous CPT [Default is discontinuous, i.e., constant colors for each
              interval].  This  option  has  no  effect  when  no  -T  is  used,  or  when  using
              -Tz_min/z_max;  in  the  first  case the input CPT remains untouched, in the second
              case it is only scaled to match the range z_min/z_max.

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

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

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

       -^ 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.


       The PostScript language originally had no accommodation for transparency.  However,  Adobe
       added  an  extension that allows developers to encode some forms of transparency using the
       PostScript language model but it is only realized when converting the  PostScript  to  PDF
       (and  via  PDF  to  any  raster  image  format).   GMT  uses this model but there are some
       limitations: Transparency can only be controlled on a per-object or per-layer basis.  This
       means  that  a  color  specifications  (such  as  those  in CPTs of given via command-line
       options) only apply to vector graphic items (i.e., text, lines, polygon fills)  or  to  an
       entire layer (which could include items such as PostScript images).  This limitation rules
       out any mechanism of controlling transparency in such images on a pixel level.


       Some of the GMT master dynamic CPTs are actually two separate CPTs  meeting  at  a  hinge.
       Usually,  colors  may  change dramatically across the hinge, which is used to separate two
       different domains (e.g., land and ocean across the shoreline, for instance).  CPTs with  a
       hinge  will  have  their  two  parts stretched to the required range separately, i.e., the
       bottom part up to the hinge will be stretched independently of the part from the hinge  to
       the  top,  according  to the prescribed new range.  If the selected range does not include
       the hinge then no such partitioning takes place.


       For best result when -T -Z is used we recommend you do no append a specific  z_inc.   This
       way  the original CPT is used exactly as is but the z boundaries are adjusted to match the
       stated limits.  Otherwise you may, depending on the nature of the input CPT, miss  aspects
       of the color changes by aliasing the signal.


       To  make  a  CPT with z-values from -200 to 200, with discrete color changes every 25, and
       using a polar blue-white-red colortable:

              gmt makecpt -Cpolar -T-200/200/25 > colors.cpt

       To make an equidistant CPT from z = -2 to  6  using  the  continuous  default  rainbow  of

              gmt makecpt -T-2/6 -Z > rainbow.cpt

       To use the GEBCO look-alike CPT with its default range for bathymetry, run

              gmt makecpt -Cgebco > my_gebco.cpt

       or simply use -Cgebco directly in the application that needs the color table.  To create a
       24-level rainbow color table suitable for plotting the depths in the data table depths.txt
       (with lon, lat, depths), run

              gmt makecpt -Cgebco depths.txt -i2 -Z -E24 > my_depths.cpt

       To use the gebco color table but reverse the z-values so it can be used for positive depth
       values, try

              gmt makecpt -Cgebco -Iz > my_positive_gebco.cpt

       To create a 24-level rainbow color table suitable for plotting  the  depths  in  the  data
       table depths.txt (with lon, lat, depths), run

       To  make  a  custom  discrete  color  table  for  depth of seismicity, using red color for
       hypocenters between 0 and 100 km, green for 100-300 km, and blue for  deep  (300-1000  km)
       earthquakes, use

              gmt makecpt -Cred,green,blue -T0,80,300,1000 -N > seis.cpt

       To make a continuous CPT from white to blue as z goes from 3 to 10, try

              gmt makecpt -Cwhite,blue -T3,10 -Z > cold.cpt

       To  make  a  wrapped (cyclic) CPT from the jet table over the interval 0 to 500, i.e., the
       color will be wrapped every 500 z-units so that we always get a color regardless of the  z
       value, try

              gmt makecpt -Cjet -T0/500 -Ww > wrapped.cpt


       Since  makecpt will also interpolate from any existing CPT you may have in your directory,
       you should not use one  of  the  listed  cpt  names  as  an  output  filename;  hence  the
       my_gebco.cpt  in  the  example.  If you do create a CPT of such a name, e.g., rainbow.cpt,
       then makecpt will read that file first and not look for the master CPT in the  shared  GMT


       gmt, grd2cpt


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