mpl.pyplot.colormaps()¶
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mpl.pyplot.colormaps()[source]¶ Matplotlib provides a number of colormaps, and others can be added using
register_cmap(). This function documents the built-in colormaps, and will also return a list of all registered colormaps if called.You can set the colormap for an image, pcolor, scatter, etc, using a keyword argument:
imshow(X, cmap=cm.hot)
or using the
set_cmap()function:imshow(X) pyplot.set_cmap('hot') pyplot.set_cmap('jet')
In interactive mode,
set_cmap()will update the colormap post-hoc, allowing you to see which one works best for your data.All built-in colormaps can be reversed by appending
_r: For instance,gray_ris the reverse ofgray.There are several common color schemes used in visualization:
- Sequential schemes
- for unipolar data that progresses from low to high
- Diverging schemes
- for bipolar data that emphasizes positive or negative deviations from a central value
- Cyclic schemes
- meant for plotting values that wrap around at the endpoints, such as phase angle, wind direction, or time of day
- Qualitative schemes
- for nominal data that has no inherent ordering, where color is used only to distinguish categories
The base colormaps are derived from those of the same name provided with Matlab:
Colormap Description autumn sequential linearly-increasing shades of red-orange-yellow bone sequential increasing black-white color map with a tinge of blue, to emulate X-ray film cool linearly-decreasing shades of cyan-magenta copper sequential increasing shades of black-copper flag repetitive red-white-blue-black pattern (not cyclic at endpoints) gray sequential linearly-increasing black-to-white grayscale hot sequential black-red-yellow-white, to emulate blackbody radiation from an object at increasing temperatures hsv cyclic red-yellow-green-cyan-blue-magenta-red, formed by changing the hue component in the HSV color space inferno perceptually uniform shades of black-red-yellow jet a spectral map with dark endpoints, blue-cyan-yellow-red; based on a fluid-jet simulation by NCSA [1] magma perceptually uniform shades of black-red-white pink sequential increasing pastel black-pink-white, meant for sepia tone colorization of photographs plasma perceptually uniform shades of blue-red-yellow prism repetitive red-yellow-green-blue-purple-...-green pattern (not cyclic at endpoints) spring linearly-increasing shades of magenta-yellow summer sequential linearly-increasing shades of green-yellow viridis perceptually uniform shades of blue-green-yellow winter linearly-increasing shades of blue-green For the above list only, you can also set the colormap using the corresponding pylab shortcut interface function, similar to Matlab:
imshow(X) hot() jet()
The next set of palettes are from the Yorick scientific visualisation package, an evolution of the GIST package, both by David H. Munro:
Colormap Description gist_earth mapmaker’s colors from dark blue deep ocean to green lowlands to brown highlands to white mountains gist_heat sequential increasing black-red-orange-white, to emulate blackbody radiation from an iron bar as it grows hotter gist_ncar pseudo-spectral black-blue-green-yellow-red-purple-white colormap from National Center for Atmospheric Research [2] gist_rainbow runs through the colors in spectral order from red to violet at full saturation (like hsv but not cyclic) gist_stern “Stern special” color table from Interactive Data Language software The following colormaps are based on the ColorBrewer color specifications and designs developed by Cynthia Brewer:
ColorBrewer Diverging (luminance is highest at the midpoint, and decreases towards differently-colored endpoints):
Colormap Description BrBG brown, white, blue-green PiYG pink, white, yellow-green PRGn purple, white, green PuOr orange, white, purple RdBu red, white, blue RdGy red, white, gray RdYlBu red, yellow, blue RdYlGn red, yellow, green Spectral red, orange, yellow, green, blue ColorBrewer Sequential (luminance decreases monotonically):
Colormap Description Blues white to dark blue BuGn white, light blue, dark green BuPu white, light blue, dark purple GnBu white, light green, dark blue Greens white to dark green Greys white to black (not linear) Oranges white, orange, dark brown OrRd white, orange, dark red PuBu white, light purple, dark blue PuBuGn white, light purple, dark green PuRd white, light purple, dark red Purples white to dark purple RdPu white, pink, dark purple Reds white to dark red YlGn light yellow, dark green YlGnBu light yellow, light green, dark blue YlOrBr light yellow, orange, dark brown YlOrRd light yellow, orange, dark red ColorBrewer Qualitative:
(For plotting nominal data,
ListedColormapshould be used, notLinearSegmentedColormap. Different sets of colors are recommended for different numbers of categories. These continuous versions of the qualitative schemes may be removed or converted in the future.)- Accent
- Dark2
- Paired
- Pastel1
- Pastel2
- Set1
- Set2
- Set3
Other miscellaneous schemes:
Colormap Description afmhot sequential black-orange-yellow-white blackbody spectrum, commonly used in atomic force microscopy brg blue-red-green bwr diverging blue-white-red coolwarm diverging blue-gray-red, meant to avoid issues with 3D shading, color blindness, and ordering of colors [3] CMRmap “Default colormaps on color images often reproduce to confusing grayscale images. The proposed colormap maintains an aesthetically pleasing color image that automatically reproduces to a monotonic grayscale with discrete, quantifiable saturation levels.” [4] cubehelix Unlike most other color schemes cubehelix was designed by D.A. Green to be monotonically increasing in terms of perceived brightness. Also, when printed on a black and white postscript printer, the scheme results in a greyscale with monotonically increasing brightness. This color scheme is named cubehelix because the r,g,b values produced can be visualised as a squashed helix around the diagonal in the r,g,b color cube. gnuplot gnuplot’s traditional pm3d scheme (black-blue-red-yellow) gnuplot2 sequential color printable as gray (black-blue-violet-yellow-white) ocean green-blue-white rainbow spectral purple-blue-green-yellow-orange-red colormap with diverging luminance seismic diverging blue-white-red nipy_spectral black-purple-blue-green-yellow-red-white spectrum, originally from the Neuroimaging in Python project terrain mapmaker’s colors, blue-green-yellow-brown-white, originally from IGOR Pro The following colormaps are redundant and may be removed in future versions. It’s recommended to use the names in the descriptions instead, which produce identical output:
Colormap Description gist_gray identical to gray gist_yarg identical to gray_r binary identical to gray_r spectral identical to nipy_spectral [5] Footnotes
[1] Rainbow colormaps, jetin particular, are considered a poor choice for scientific visualization by many researchers: Rainbow Color Map (Still) Considered Harmful[2] Resembles “BkBlAqGrYeOrReViWh200” from NCAR Command Language. See Color Table Gallery [3] See Diverging Color Maps for Scientific Visualization by Kenneth Moreland. [4] See A Color Map for Effective Black-and-White Rendering of Color-Scale Images by Carey Rappaport [5] Changed to distinguish from ColorBrewer’s Spectral map. spectral()still works, butset_cmap('nipy_spectral')is recommended for clarity.