Python Matplotlib/底图颜色循环 [英] Python Matplotlib/Basemap Color Cycling

问题描述

我是 Python 和其他程序的新手，我正在尝试使用 for 循环对集合成员绘制集合预测的 21 个成员，每个成员都有一个专用的数字 1-21.当我绘制地图时，所有成员都变成蓝色.我对颜色图进行了一些研究，发现默认图没有索引，即我不能像调用列表或数组一样调用 colormap[1].是否有任何索引的色彩图，或者有什么办法解决?简而言之，我想使用简单的数字循环显示颜色，为每个预测成员使用不同的颜色.

I'm new to Python and the other programs and I'm attempting to plot 21 members of an ensemble forecast using for loops over the ensemble members, each one having a dedicated number 1-21. When I plot the map, the members all come up blue. I've done some research on colormaps and found that the default maps are not indexed, i.e. I can't call colormap[1] as if it were a list or array. Are there any indexed colormaps out there, or is there any way around this? Simply put, I want to cycle through colors, a different one for each forecast member, using simple numerics.

推荐答案

您可以使用 ax.set_prop_cycle 指定要循环的颜色列表.

You could use ax.set_prop_cycle to specify a list of colors to cycle through.

颜色图是可调用的，因此生成颜色的一种简单方法是将 0 到 1 之间的浮点序列传递给颜色图，然后颜色图将返回一个 RGBA 颜色数组.

Colormaps are callable, so an easy way to generate colors is to pass an sequence of floats between 0 and 1 to a colormap, which will then return an array of RGBA colors.

例如，

In [93]: jet = plt.cm.jet

In [94]: jet([0,0.5,1])
Out[94]: 
array([[ 0.        ,  0.        ,  0.5       ,  1.        ],
       [ 0.49019608,  1.        ,  0.47754586,  1.        ],
       [ 0.5       ,  0.        ,  0.        ,  1.        ]])

<小时>

import matplotlib.pylab as plt
import matplotlib.rcsetup as rcsetup
import numpy as np

jet = plt.cm.jet
fig, ax = plt.subplots()
N = 20
idx = np.linspace(0, 1, N)
ax.set_prop_cycle(rcsetup.cycler('color', jet(idx)))
x = np.linspace(0, 100, 200)
for i in range(1, N+1):
    ax.plot(x, np.sin(x)+i)
ax.set_ylim(0, N+1)
plt.show()

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