NAME

       makecpt - Make GMT color palette tables

SYNOPSIS

       makecpt  [ -Ctable ] [ -I ] [ -N ] [ -Q[i|o] ] [ -Tz0/z1/dz | -Tztable]
       [ -V ] [ -Z ]

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.

OPTIONS

       -C     Selects the master color table table to use  in  the  interpola-
              tion.  Choose among the built-in tables (type makecpt to see the
              list) or give the name of an existing cptfile [Default  gives  a
              rainbow cpt file].

       -I     Reverses the sense of color progression in the master cptfile.

       -N     Do  Not  write  out  the  background,  foreground, and NaN-color
              fields [Default  will  write  the  parameters  COLOR_BACKGROUND,
              COLOR_FOREGROUND, and COLOR_NAN in your .gmtdefaults4 file.

       -Q     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 col-
              ors, and writes out z.

       -T     Defines the range of the new cptfile by giving  the  lowest  and
              highest  z-value  and the interval. Alternatively, give the name
              of a ASCII file that has one z-value per record. If  not  given,
              the existing range in the master cptfile will be used intact.

       -V     Selects verbose mode, which will send progress reports to stderr
              [Default runs "silently"].

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

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:

       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:

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

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

       makecpt -Cgebco > my_gebco.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(l), grd2cpt(l)



GMT4.0                            1 Oct 2004                        MAKECPT(l)