1MAKECPT(1) Generic Mapping Tools MAKECPT(1)
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6 makecpt - Make GMT color palette tables
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9 makecpt [ -Ctable ] [ -D ] [ -I ] [ -M ] [ -N ] [ -Q[i|o] ] [
10 -Tz0/z1/dz | -Tztable] [ -V ] [ -Z ]
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13 makecpt is a utility that will help you make color palette tables (cpt
14 files). You define an equidistant set of contour intervals or pass
15 your own z-table, and create a new cpt file based on an existing master
16 cpt file. The resulting cpt file can be reversed relative to the mas‐
17 ter cpt, and can be made continuous or discrete.
18 The color palette includes three additional colors beyond the range of
19 z-values. These are the background color (B) assigned to values lower
20 than the lowest z-value, the foreground color (F) assigned to values
21 higher than the highest z-value, and the NaN color (N) painted
22 whereever values are undefined.
23 If the master cpt file includes B, F, and N entries, these will be
24 copied into the new master file. If not, the parameters COLOR_BACK‐
25 GROUND, COLOR_FOREGROUND, and COLOR_NAN from the .gmtdefaults4 file or
26 the command line will be used. This default behavior can be overruled
27 using the options -D, -M or -N.
28 The color model (RGB, HSV or CMYK) of the palette created by makecpt
29 will be the same as specified in the header of the master cpt file.
30 When there is no COLOR_MODEL entry in the master cpt file, the
31 COLOR_MODEL specified in the .gmtdefaults4 file or on the command line
32 will be used.
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35 -C Selects the master color table table to use in the interpola‐
36 tion. Choose among the built-in tables (type makecpt to see the
37 list) or give the name of an existing cpt file [Default gives a
38 rainbow cpt file].
39 -D Select the colors for lowest and highest z-values in the output
41 cpt file as the back- and foreground colors that will be written
42 to the cpt file [Default uses the colors specified in the master
43 file, or those defined by the parameters COLOR_BACKGROUND,
44 COLOR_FOREGROUND, and COLOR_NAN].
45 -I Reverses the sense of color progression in the master cpt file.
47 Also exchanges the foreground and background colors, including
48 those specified by the parameters COLOR_BACKGROUND and
49 COLOR_FOREGROUND.
50 -M Overrule background, foreground, and NaN colors specified in the
52 master cpt file with the values of the parameters COLOR_BACK‐
53 GROUND, COLOR_FOREGROUND, and COLOR_NAN specified in the .gmtde‐
54 faults4 file or on the command line. When combined with -D,
55 only COLOR_NAN is considered.
56 -N Do not write out the background, foreground, and NaN-color
58 fields [Default will write them].
59 -Q Selects a logarithmic interpolation scheme [Default is linear].
61 -Qi expects input z-values to be log10(z), assigns colors, and
62 writes out z [Default]. -Qo takes log10(z) first, assigns col‐
63 ors, and writes out z.
64 -T Defines the range of the new cpt file by giving the lowest and
66 highest z-value and the interval. Alternatively, give the name
67 of a ASCII file that has one z-value per record. If not given,
68 the existing range in the master cpt file will be used intact.
69 -V Selects verbose mode, which will send progress reports to stderr
71 [Default runs "silently"].
72 -Z Creates a continuous cpt file [Default is discontinuous, i.e.
74 constant colors for each interval].
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77 To make a cpt file with z-values from -200 to 200, with discrete color
78 changes every 25, and using a polar blue-white-red colortable:
79 makecpt -Cpolar -T-200/200/25 > colors.cpt
81 To make an equidistant cpt file from z = -2 to 6, in steps of 1, using
83 continuous default rainbow colors:
84 makecpt -T-2/6/1 -Z > rainbow.cpt
86 To make a GEBCO look-alike cpt file for bathymetry, run
88 makecpt -Cgebco > my_gebco.cpt
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92 Since makecpt will also interpolate from any existing .cpt file you may
93 have in your directory, you cannot use one of the listed cpt names as
94 an output filename; hence the my_gebco.cpt in the example.
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97 GMT(1), grd2cpt(1)
98GMT 4.3.1 15 May 2008 MAKECPT(1)