如何在 matplotlib 1.4 中使用 viridis

Question

我想使用颜色图 "viridis"（http://bids.github.io/colormap/), and I won't be updating to the development version 1.5 quite yet. Thus, I have downloaded colormaps.py from https://github.com/BIDS/colormap。不幸的是，我无法让它工作。这就是我所做的：

import matplotlib.pyplot as plt
import matplotlib.image as mpimg
import numpy as np

import colormaps as cmaps

img=mpimg.imread('stinkbug.png')
lum_img = np.flipud(img[:,:,0])

plt.set_cmap(cmaps.viridis)
imgplot = plt.pcolormesh(lum_img)

这给了我一个 ValueError，以

结尾的回溯

ValueError: Colormap viridis is not recognized. Possible values are: Spectral, summer, coolwarm, ...

（然后是最初安装的颜色图的完整列表。）

关于如何解决这个问题有什么想法吗？

Answer 1

与其使用需要 matplotlib.colors.Colormap 实例的 set_cmap，不如直接在 pcolormesh 调用

中设置 cmap

(cmaps.viridis 是一个 matplotlib.colors.ListedColormap)

import matplotlib.pyplot as plt
import matplotlib.image as mpimg
import numpy as np

import colormaps as cmaps

img=mpimg.imread('stinkbug.png')
lum_img = np.flipud(img[:,:,0])

imgplot = plt.pcolormesh(lum_img, cmap=cmaps.viridis)

Answer 2

要使用 set_cmap 将 viridis 设置为您的颜色图，您必须先注册它：

import colormaps as cmaps
plt.register_cmap(name='viridis', cmap=cmaps.viridis)
plt.set_cmap(cmaps.viridis)

img=mpimg.imread('stinkbug.png')
lum_img = np.flipud(img[:,:,0])
imgplot = plt.pcolormesh(lum_img)

Answer 3

我所做的只是复制

_viridis_data = [[0.267004, 0.004874, 0.329415],
                 [0.268510, 0.009605, 0.335427],
                 [0.269944, 0.014625, 0.341379],
                 :
                 [0.983868, 0.904867, 0.136897],
                 [0.993248, 0.906157, 0.143936]]

来自 https://github.com/BIDS/colormap/blob/master/colormaps.py

并添加：

from matplotlib.colors import ListedColormap

viridis = ListedColormap(_viridis_data, name='viridis')

plt.register_cmap(name='viridis', cmap=viridis)
plt.set_cmap(viridis)

Answer 4

从 here 下载 colormaps.py，然后：

import os,sys
scriptpath = "/Your downloading path/colormap-master/"
sys.path.append(os.path.abspath(scriptpath))
import colormaps as cmaps

完成！

如何在 matplotlib 1.4 中使用 viridis

How to use viridis in matplotlib 1.4

python

matplotlib

colormap