在使用GMT繪圖時(shí)，比如同樣是rainbow色度條，在水儲(chǔ)量大小表示時(shí)，藍(lán)色更能代表水量充足，而黃色是虧損；而如果是表示溫度，暖色可以代表高溫，冷色低溫。因此在科研繪圖中，我們需要翻轉(zhuǎn)色度條。

下面我舉一例：

比如是如下的情況，采用等效水高表示：如果需要翻轉(zhuǎn)色度條，需要更改makecpt語(yǔ)句

makecpt -Cjet -T-0.6/0.6/0.05? >1.cpt【之前】

makecpt -Cjet -T-0.6/0.6/0.05? -I>1.cpt【翻轉(zhuǎn)】

我們可以看到只需要在命令中加上 -I即可。

makecpt命令的使用說(shuō)明：

?makecpt [-A[+]<transparency>] [-C<cpt>|colors] [-D[i|o]] [-E<nlevels>] [-F[R|r|h|c][+c]] [-G<zlo>/<zhi>]

? ? ? ? [-I[c][z]] [-L] [-M] [-N] [-Q[i|o]] [-T<z_min>/<z_max>[/<z_inc>[+n]] | -T<table> | -T<z1,z2,...zn>] [-V[<level>]] [-W[w]]

? ? ? ? [-Z] [-bi[<ncol>][t][w][+L|B]] [-di<nodata>] [-i<cols>[+l][+s<scale>][+o<offset>][,...]]

? ? ? ? [-ho[<nrecs>][+c][+d][+r<remark>][+t<title>]]

? ? ? ? OPTIONS:

? ? ? ? -A Set constant transparency for all colors; prepend + to also include back-, for-, and nan-colors [0]

? ? ? ? -C Specify a colortable [Default is rainbow]:

? ? ? ? ? ?[Notes: R=Default z-range, H=Hinge, C=colormodel]

? ? ? ? ? ?---------------------------------------------------------------------------------------

? ? ? ? ? ?abyss? ? ? ?: Black/dark blue to lightblue for bathymetry [R=-8000/0, C=RGB]

? ? ? ? ? ?bathy? ? ? ?: Like abyss but via aquamarine at mid-depths [R=-8000/0, C=RGB]

? ? ? ? ? ?categorical : Color table particularly suitable for categorical data [vRGB]

? ? ? ? ? ?cool? ? ? ? : Linear change from blue to magenta [C=RGB]

? ? ? ? ? ?copper? ? ? : Dark to light copper brown [C=RGB]

? ? ? ? ? ?cubhelix? ? : Intensity colormap via cube helix by Dave Green [C=RGB]

? ? ? ? ? ?cyclic? ? ? : Cyclic colormap, spans 360 degrees of hue [C=HSV]

? ? ? ? ? ?dem1? ? ? ? : Digital Elevation Model (DEM) scale by Thomas Dewez [R=0/800, C=RGB]

? ? ? ? ? ?dem2? ? ? ? : Digital Elevation Model (DEM) scale by Dewez/Wessel [R=0/4900, C=RGB]

? ? ? ? ? ?dem3? ? ? ? : Digital Elevation Model (DEM) scale by Paul Wessel [R=0/6000, C=RGB]

? ? ? ? ? ?dem4? ? ? ? : Digital Elevation Model (DEM) scale for Wikipedia figures [R=0/1500, C=RGB]

? ? ? ? ? ?drywet? ? ? : Goes from dry to wet colors [C=RGB]

? ? ? ? ? ?earth? ? ? ?: Colors for global bathymetry/topography relief [R=-11000/9000, H=0, C=RGB]

? ? ? ? ? ?elevation? ?: Washed-out colors for topography [R=0/7000, C=RGB]

? ? ? ? ? ?etopo1? ? ? : Colormap used in the ETOPO1 global relief map [R=-11000/8500, H=0, C=RGB]

? ? ? ? ? ?gebco? ? ? ?: Colors for GEBCO bathymetric charts [R=-7000/0, C=RGB]

? ? ? ? ? ?geo? ? ? ? ?: Colors for global bathymetry/topography relief [R=-8000/8000, H=0, C=RGB]

? ? ? ? ? ?globe? ? ? ?: Colors for global bathymetry/topography relief [R=-10000/10000, H=0, C=RGB]

? ? ? ? ? ?gray? ? ? ? : Gray linear ramp from black to white [C=RGB]

? ? ? ? ? ?haxby? ? ? ?: Bill Haxby's color scheme for geoid & gravity [C=RGB]

? ? ? ? ? ?hot? ? ? ? ?: Black through red and yellow to white [C=RGB]

? ? ? ? ? ?ibcso? ? ? ?: The IBCSO bathymetry colors [R=-12000/0, C=RGB]

? ? ? ? ? ?inferno? ? ?: New colormap Option B from matplotlib [C=RGB]

? ? ? ? ? ?jet? ? ? ? ?: Dark to light blue, white, yellow and red [C=RGB]

? ? ? ? ? ?magma? ? ? ?: New colormap Option A from matplotlib [C=RGB]

? ? ? ? ? ?nighttime? ?: Colors for DMSP-OLS Nighttime Lights Time Series [C=HSV]

? ? ? ? ? ?no_green? ? : For those who hate green [H=0, C=RGB]

? ? ? ? ? ?ocean? ? ? ?: White-green-blue bathymetry scale [R=-8000/0, C=RGB]

? ? ? ? ? ?paired? ? ? : Qualitative color map with 6 pairs of colors [C=RGB]

? ? ? ? ? ?panoply? ? ?: Default colormap of Panoply [C=RGB]

? ? ? ? ? ?plasma? ? ? : New colormap Option C from matplotlib [C=RGB]

? ? ? ? ? ?polar? ? ? ?: Blue via white to red [H=0, C=RGB]

? ? ? ? ? ?rainbow? ? ?: Rainbow: magenta-blue-cyan-green-yellow-red [C=HSV]

? ? ? ? ? ?red2green? ?: Polar scale from red to green via white [H=0, C=RGB]

? ? ? ? ? ?relief? ? ? : Wessel/Martinez colors for topography [R=-8000/+8000, H=0, C=RGB]

? ? ? ? ? ?seafloor? ? : Purple-blue-white bathymetry scale [R=-6000/0, C=RGB]

? ? ? ? ? ?sealand? ? ?: Smith bathymetry/topography scale [R=-6000/+3000, H=0, C=HSV]

? ? ? ? ? ?seis? ? ? ? : R-O-Y-G-B seismic tomography colors [C=RGB]

? ? ? ? ? ?split? ? ? ?: Like polar, but via black instead of white [H=0, C=RGB]

? ? ? ? ? ?terra? ? ? ?: Colors for global bathymetry/topography relief [R=-7000/7000, H=0, C=RGB]

? ? ? ? ? ?topo? ? ? ? : Sandwell/Anderson colors for topography [R=-7000/+7000, H=0, C=HSV]

? ? ? ? ? ?viridis? ? ?: New colormap Option D from matplotlib [C=RGB]

? ? ? ? ? ?world? ? ? ?: Colors for global bathymetry/topography relief [R=-7000/7000, H=0, C=RGB]

? ? ? ? ? ?wysiwyg? ? ?: 20 well-separated RGB colors [C=RGB]

? ? ? ? ? ?---------------------------------------------------------------------------------------

? ? ? ? ? ?[For more, visit http://soliton.vm.bytemark.co.uk/pub/cpt-city/]

? ? ? ? ? ?Alternatively, specify -Ccolor1,color2[,color3,...] to build a linear

? ? ? ? ? ?continuous CPT from those colors automatically.

? ? ? ? -D Set back- and foreground color to match the bottom/top limits

? ? ? ? ? ?in the output CPT [Default uses color table]. append i to match the

? ? ? ? ? ?bottom/top values in the input CPT.

? ? ? ? -E Use <nlevels> equidistant color levels from zmin to zmax.

? ? ? ? ? ?This option implies we read data from given command-line files [or stdin] to

? ? ? ? ? ?determine data range (use -i to select a data column, else last column is used).

? ? ? ? ? ?If <nlevels> is not set we use the number of color slices in the chosen CPT.

? ? ? ? -F Select the color model for output (R for r/g/b or grayscale or colorname,

? ? ? ? ? ?r for r/g/b only, h for h-s-v, c for c/m/y/k) [Default uses the input model]

? ? ? ? ? ?append +c to output a discrete CPT in categorical CPT format.

? ? ? ? -G Truncate incoming CPT to be limited to the z-range <zlo>/<zhi>.

? ? ? ? ? ?To accept one of the incoming limits, set that limit to NaN.

? ? ? ? -I Reverse sense of CPT in one or two ways:

? ? ? ? ? ?-Ic Reverse sense of color table as well as back- and foreground color [Default].

? ? ? ? ? ?-Iz Reverse sign of z-values in the color table (takes affect before -G, T are consulted).【此處便是幫助文檔中提到的具體的使用】

? ? ? ? -M Use GMT defaults to set back-, foreground, and NaN colors

? ? ? ? ? ?[Default uses the settings in the color table].

? ? ? ? -N Do not write back-, foreground, and NaN colors [Default will].

? ? ? ? -Q Assign a logarithmic colortable [Default is linear].

? ? ? ? ? ?-Qi: z-values are log10(z). Assign colors and write z [Default].

? ? ? ? ? ?-Qo: z-values are z; take log10(z), assign colors and write z.

? ? ? ? ? ? ? ? If -T<z_min/z_max/z_inc> is given, then z_inc must be 1, 2, or 3

? ? ? ? ? ? ? ? (as in logarithmic annotations; see -B in psbasemap).

? ? ? ? -T Give <z_min>/<z_max> to change the z-range for the colorscale in z-units.

? ? ? ? ? ?append /<z_inc> to sample the cpt discretely instead, or append +n to <z_inc>

? ? ? ? ? ?to let <z_inc> indicate the number of z-values to produce instead.

? ? ? ? ? ?Alternatively, supply (1) a filename with custom z-values or

? ? ? ? ? ?(2) a comma-separated list of custom z-values.

? ? ? ? -V Change the verbosity level (currently v).

? ? ? ? ? ?Choose among 6 levels; each level adds more messages:

? ? ? ? ? ? ?q - Quiet, not even fatal error messages.

? ? ? ? ? ? ?n - Normal verbosity: only error messages.

? ? ? ? ? ? ?c - Also produce compatibility warnings [Default when no -V is used].

? ? ? ? ? ? ?v - Verbose progress messages [Default when -V is used].

? ? ? ? ? ? ?l - Long verbose progress messages.

? ? ? ? ? ? ?d - Debugging messages.

? ? ? ? -W Do not interpolate color palette. Alternatively, append w for a wrapped CPT.

? ? ? ? -Z Create a continuous color palette [Default is discontinuous,

? ? ? ? ? ?i.e., constant color intervals]. Without -T or when using -T<z_min>/<z_max> this

? ? ? ? ? ?has no effect; the input palette table is used untouched with possible scaling.

? ? ? ? -bi For binary input; [<n>]<type>[w][+L|B]; <type> = c|u|h|H|i|I|l|L|f|D.

? ? ? ? ? ? Prepend <n> for the number of columns for each <type>.

? ? ? ? -di Replace any <nodata> in input data with NaN.

? ? ? ? -h[i][<n>][+c][+d][+r<remark>][+t<title>] Input/output file has [0] Header record(s) [OFF]

? ? ? ? ? ?Optionally, append i for input only and/or number of header records [0].

? ? ? ? ? ? ?-hi turns off the writing of all headers on output.

? ? ? ? ? ?append +c to add header record with column information [none].

? ? ? ? ? ?append +d to delete headers before adding new ones [Default will append headers].

? ? ? ? ? ?append +r to add a <remark> comment to the output [none].

? ? ? ? ? ?append +t to add a <title> comment to the output [none].

? ? ? ? ? ? ?(these strings may contain \n to indicate line-breaks)

? ? ? ? ? ?For binary files, <n> is considered to mean number of bytes.

? ? ? ? -i Sets alternate input column order and optional transformations [Default reads all columns in order].

? ? ? ? -^ (or -) Print short synopsis message.

? ? ? ? -+ (or +) Print longer synopsis message.

? ? ? ? -? (or no arguments) Print this usage message

? ? ? ? (See gmt.conf man page for GMT default parameters).

【gmt小技巧@我是水怪的哥----2021-12-26】