Matplotlib:在等高线图上将散点图绘制到前景

问题描述：

有谁知道在 matplotlib 中将散点图带到前台的方法吗?我必须在轮廓顶部显示散点图，但默认情况下它绘制在下面...

Does anyone know a way to bring a scatter plot to the foreground in matplotlib? I have to display the scatter plotting on top of the contour, but by default it is plotted underneath...

提前致谢！

答

您可以使用 zorder 例如的参数scatter 方法.

要演示，请参见下面的代码，其中左侧子图中的散点图具有 zorder=1，右侧子图中的散点图具有 zorder=-1.zorder 最高的对象被放置在顶部.这意味着散点将放置在第一个子图中的等高线顶部，而它位于第二个子图中的下方.

To demonstrate, see the code below, where the scatter plot in the left subplot has zorder=1 and in the right subplot it has zorder=-1. The object with the highest zorder is placed on top. This means that the scatter will be placed on top of the contour in the first subplot, while it is placed underneath in the second subplot.

import numpy as np
import matplotlib.cm as cm
import matplotlib.mlab as mlab
import matplotlib.pyplot as plt

delta = 0.025
x = np.arange(-3.0, 3.0, delta)
y = np.arange(-2.0, 2.0, delta)
X, Y = np.meshgrid(x, y)
Z1 = mlab.bivariate_normal(X, Y, 1.0, 1.0, 0.0, 0.0)
Z2 = mlab.bivariate_normal(X, Y, 1.5, 0.5, 1, 1)
Z = 10.0 * (Z2 - Z1)

norm = cm.colors.Normalize(vmax=abs(Z).max(), vmin=-abs(Z).max())
cmap = cm.PRGn

levels = np.arange(-2.0, 1.601, 0.4)

fig, axes = plt.subplots(1,2, sharey=True)

for ax, zord in zip(axes, [1, -1]):
    ax.contourf(X, Y, Z, levels,
                cmap=cm.get_cmap(cmap, len(levels)-1),
                norm=norm)
    ax.autoscale(False) # To avoid that the scatter changes limits
    ax.scatter(np.random.uniform(-3,3,10),
               np.random.uniform(-2,2,10),
               zorder=zord)
    ax.set_title('Scatter with zorder={0}'.format(zord))

Matplotlib:在等高线图上将散点图绘制到前景

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