makecpt - Make GMT color palette tables
makecpt [ -Ctable ] [ -I ] [ -N ] [ -Q[i|o] ] [ -Tz0/z1/dz | -Tztable]
[ -V ] [ -Z ]
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.
-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].
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
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.
GMT4.0 1 Oct 2004 MAKECPT(l)
Man(1) output converted with