NAME

       makecpt - Make GMT color palette tables

SYNOPSIS

       makecpt  [ [+]transparency ] [ cpt ] [ [i|o] ] [ [nlevels] ] [ [R|r|h|c ] [ zlo/zhi ] [  ]
       [  ] [  ] [ [i|o] ] [ z_min/z_max[/z_inc[+]] | -Tztable ] [ [level] ] [  ] [  ]

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

DESCRIPTION

       makecpt is a utility that will help you make color palette tables (CPT files). You  define
       an  equidistant  set  of  contour intervals or pass your own z-table, and create a new CPT
       file based on an existing master CPT file. The resulting CPT file 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: http://soliton.vm.bytemark.co.uk/pub/cpt-city/.

       The CPT file 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  file 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 file. When there is no COLOR_MODEL entry in the
       master CPT file, the COLOR_MODEL specified in the gmt.conf file or  on  the  command  line
       will be used.

REQUIRED ARGUMENTS

       None.

OPTIONAL ARGUMENTS

       -A[+]transparency
              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
              (opaque)].

       -Ccpt  Selects  the master color table CPT file 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  file  [Default  gives  a  rainbow CPT file].  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 ).

       -D[i|o]
              Select the back- and foreground colors to match the colors for lowest  and  highest
              z-values  in  the  output CPT file [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 file.

       -E[nlevels]
              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 file.

       -F[R|r|h|c]
              Force  output CPT file 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).

       -Gzlo/zhi
              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.

       -I     Reverses the sense of color progression in the master CPT file. Also exchanges  the
              foreground  and  background  colors,  including  those  specified by the parameters
              COLOR_BACKGROUND and COLOR_FOREGROUND.

       -M     Overrule background, foreground, and NaN colors specified in the  master  CPT  file
              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].

       -Q[i|o]
              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
              Defines the range of the new CPT file by giving the lowest and highest z-value  and
              interval.  When  used  with  -C and z_inc is not specified, the number of intervals
              remains the same as in the input palette. If z_inc is specified with a  trailing  +
              we 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. If -T is not  given,  the
              existing range in the master CPT file will be used intact.

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

       -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.

       -Z     Creates a continuous CPT file [Default is discontinuous, i.e., constant colors  for
              each interval].

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

       -+ 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 options, then
              exits.

       --version
              Print GMT version and exit.

       --show-datadir
              Print full path to GMT share directory and exit.

EXAMPLES

       To make a CPT file 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 file from z = -2 to 6, in steps of 1, using continuous default
       rainbow colors:

              gmt makecpt -T-2/6/1 -Z > rainbow.cpt

       To make a GEBCO look-alike CPT file for bathymetry, run

              gmt makecpt -Cgebco > my_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

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

BUGS

       Since  makecpt  will  also  interpolate  from  any  existing CPT file you may have in your
       directory, you cannot use one of the listed cpt names as an  output  filename;  hence  the
       my_gebco.cpt in the example.

SEE ALSO

       gmt, grd2cpt

COPYRIGHT

       2015, P. Wessel, W. H. F. Smith, R. Scharroo, J. Luis, and F. Wobbe