Matplotlib 散点图图例 [英] Matplotlib scatter plot legend

问题描述

我创建了一个 4D 散点图来表示特定区域的不同温度.当我创建图例时，图例显示了正确的符号和颜色，但在其中添加了一条线.我使用的代码是:

I created a 4D scatter plot graph to represent different temperatures in a specific area. When I create the legend, the legend shows the correct symbol and color but adds a line through it. The code I'm using is:

colors=['b', 'c', 'y', 'm', 'r']
lo = plt.Line2D(range(10), range(10), marker='x', color=colors[0])
ll = plt.Line2D(range(10), range(10), marker='o', color=colors[0])
l = plt.Line2D(range(10), range(10), marker='o',color=colors[1])
a = plt.Line2D(range(10), range(10), marker='o',color=colors[2])
h = plt.Line2D(range(10), range(10), marker='o',color=colors[3])
hh = plt.Line2D(range(10), range(10), marker='o',color=colors[4])
ho = plt.Line2D(range(10), range(10), marker='x', color=colors[4])
plt.legend((lo,ll,l,a, h, hh, ho),('Low Outlier', 'LoLo','Lo', 'Average', 'Hi', 'HiHi', 'High Outlier'),numpoints=1, loc='lower left', ncol=3, fontsize=8)

我尝试将 Line2D 更改为 Scatter 和 scatter.Scatter 返回错误，scatter 更改图形并返回错误.

I tried changing Line2D to Scatter and scatter. Scatter returned an error and scatter changed the graph and returned an error.

使用 scatter，我将 range(10) 更改为包含数据点的列表.每个列表包含 x、y 或 z 变量.

With scatter, I changed the range(10) to the lists containing the data points. Each list contains either the x, y, or z variable.

lo = plt.scatter(xLOutlier, yLOutlier, zLOutlier, marker='x', color=colors[0])
ll = plt.scatter(xLoLo, yLoLo, zLoLo, marker='o', color=colors[0])
l = plt.scatter(xLo, yLo, zLo, marker='o',color=colors[1])
a = plt.scatter(xAverage, yAverage, zAverage, marker='o',color=colors[2])
h = plt.scatter(xHi, yHi, zHi, marker='o',color=colors[3])
hh = plt.scatter(xHiHi, yHiHi, zHiHi, marker='o',color=colors[4])
ho = plt.scatter(xHOutlier, yHOutlier, zHOutlier, marker='x', color=colors[4])
plt.legend((lo,ll,l,a, h, hh, ho),('Low Outlier', 'LoLo','Lo', 'Average', 'Hi', 'HiHi',     'High Outlier'),scatterpoints=1, loc='lower left', ncol=3, fontsize=8)

当我运行这个时，图例不再存在，它是角落里一个白色的小盒子，里面什么也没有.

When I run this, the legend no longer exists, it is a small white box in the corner with nothing in it.

有什么建议吗?

推荐答案

二维散点图

使用 matplotlib.pyplot 模块的 scatter 方法应该可以工作(至少在 matplotlib 1.2.1 和 Python 2.7.5 中)，如下面的示例代码.此外，如果您使用散点图，请在图例调用中使用 scatterpoints=1 而不是 numpoints=1 以使每个图例条目只有一个点.

2D scatter plot

Using the scatter method of the matplotlib.pyplot module should work (at least with matplotlib 1.2.1 with Python 2.7.5), as in the example code below. Also, if you are using scatter plots, use scatterpoints=1 rather than numpoints=1 in the legend call to have only one point for each legend entry.

在下面的代码中，我使用了随机值，而不是一遍又一遍地绘制相同的范围，使所有的图都可见(即不相互重叠).

In the code below I've used random values rather than plotting the same range over and over, making all the plots visible (i.e. not overlapping each other).

import matplotlib.pyplot as plt
from numpy.random import random

colors = ['b', 'c', 'y', 'm', 'r']

lo = plt.scatter(random(10), random(10), marker='x', color=colors[0])
ll = plt.scatter(random(10), random(10), marker='o', color=colors[0])
l  = plt.scatter(random(10), random(10), marker='o', color=colors[1])
a  = plt.scatter(random(10), random(10), marker='o', color=colors[2])
h  = plt.scatter(random(10), random(10), marker='o', color=colors[3])
hh = plt.scatter(random(10), random(10), marker='o', color=colors[4])
ho = plt.scatter(random(10), random(10), marker='x', color=colors[4])

plt.legend((lo, ll, l, a, h, hh, ho),
           ('Low Outlier', 'LoLo', 'Lo', 'Average', 'Hi', 'HiHi', 'High Outlier'),
           scatterpoints=1,
           loc='lower left',
           ncol=3,
           fontsize=8)

plt.show()

要绘制 3D 散点图，请使用 plot 方法，因为图例不支持 scatter 方法返回的 Patch3DCollectionAxes3D 实例.要指定标记样式，您可以将其作为位置参数包含在方法调用中，如下例所示.可选地，可以同时包含 linestyle 和 marker 参数的参数.

To plot a scatter in 3D, use the plot method, as the legend does not support Patch3DCollection as is returned by the scatter method of an Axes3D instance. To specify the markerstyle you can include this as a positional argument in the method call, as seen in the example below. Optionally one can include argument to both the linestyle and marker parameters.

import matplotlib.pyplot as plt
from numpy.random import random
from mpl_toolkits.mplot3d import Axes3D

colors=['b', 'c', 'y', 'm', 'r']

ax = plt.subplot(111, projection='3d')

ax.plot(random(10), random(10), random(10), 'x', color=colors[0], label='Low Outlier')
ax.plot(random(10), random(10), random(10), 'o', color=colors[0], label='LoLo')
ax.plot(random(10), random(10), random(10), 'o', color=colors[1], label='Lo')
ax.plot(random(10), random(10), random(10), 'o', color=colors[2], label='Average')
ax.plot(random(10), random(10), random(10), 'o', color=colors[3], label='Hi')
ax.plot(random(10), random(10), random(10), 'o', color=colors[4], label='HiHi')
ax.plot(random(10), random(10), random(10), 'x', color=colors[4], label='High Outlier')

plt.legend(loc='upper left', numpoints=1, ncol=3, fontsize=8, bbox_to_anchor=(0, 0))

plt.show()

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