如何在Python中用散点图绘制散点图?

问题:如何在Python中用散点图绘制散点图?

在Python中,使用Matplotlib,如何绘制带有圆的散点图?目标是在已经由绘制的一些彩色磁盘周围绘制空圆scatter(),以便突出显示它们,理想情况下不必重新绘制彩色圆。

我试过了facecolors=None,无济于事。

In Python, with Matplotlib, how can a scatter plot with empty circles be plotted? The goal is to draw empty circles around some of the colored disks already plotted by scatter(), so as to highlight them, ideally without having to redraw the colored circles.

I tried facecolors=None, to no avail.


回答 0

从分散的文档中:

Optional kwargs control the Collection properties; in particular:

    edgecolors:
        The string none to plot faces with no outlines
    facecolors:
        The string none to plot unfilled outlines

请尝试以下操作:

import matplotlib.pyplot as plt 
import numpy as np 

x = np.random.randn(60) 
y = np.random.randn(60)

plt.scatter(x, y, s=80, facecolors='none', edgecolors='r')
plt.show()

注意:对于其他类型的地块看到这个帖子的使用markeredgecolormarkerfacecolor

From the documentation for scatter:

Optional kwargs control the Collection properties; in particular:

    edgecolors:
        The string ‘none’ to plot faces with no outlines
    facecolors:
        The string ‘none’ to plot unfilled outlines

Try the following:

import matplotlib.pyplot as plt 
import numpy as np 

x = np.random.randn(60) 
y = np.random.randn(60)

plt.scatter(x, y, s=80, facecolors='none', edgecolors='r')
plt.show()

Note: For other types of plots see this post on the use of markeredgecolor and markerfacecolor.


回答 1

这些行得通吗?

plt.scatter(np.random.randn(100), np.random.randn(100), facecolors='none')

或使用plot()

plt.plot(np.random.randn(100), np.random.randn(100), 'o', mfc='none')

Would these work?

plt.scatter(np.random.randn(100), np.random.randn(100), facecolors='none')

or using plot()

plt.plot(np.random.randn(100), np.random.randn(100), 'o', mfc='none')


回答 2

这是另一种方式:这会在当前轴,图或图像等上添加一个圆:

from matplotlib.patches import Circle  # $matplotlib/patches.py

def circle( xy, radius, color="lightsteelblue", facecolor="none", alpha=1, ax=None ):
    """ add a circle to ax= or current axes
    """
        # from .../pylab_examples/ellipse_demo.py
    e = Circle( xy=xy, radius=radius )
    if ax is None:
        ax = pl.gca()  # ax = subplot( 1,1,1 )
    ax.add_artist(e)
    e.set_clip_box(ax.bbox)
    e.set_edgecolor( color )
    e.set_facecolor( facecolor )  # "none" not None
    e.set_alpha( alpha )

(由于,图片中的圆圈被挤压成椭圆形imshow aspect="auto")。

Here’s another way: this adds a circle to the current axes, plot or image or whatever :

from matplotlib.patches import Circle  # $matplotlib/patches.py

def circle( xy, radius, color="lightsteelblue", facecolor="none", alpha=1, ax=None ):
    """ add a circle to ax= or current axes
    """
        # from .../pylab_examples/ellipse_demo.py
    e = Circle( xy=xy, radius=radius )
    if ax is None:
        ax = pl.gca()  # ax = subplot( 1,1,1 )
    ax.add_artist(e)
    e.set_clip_box(ax.bbox)
    e.set_edgecolor( color )
    e.set_facecolor( facecolor )  # "none" not None
    e.set_alpha( alpha )

(The circles in the picture get squashed to ellipses because imshow aspect="auto" ).


回答 3

在matplotlib 2.0中,有一个名为的参数fillstyle ,可以更好地控制标记的填充方式。就我而言,我已将其与错误栏一起使用,但它可用于一般http://matplotlib.org/api/_as_gen/matplotlib.axes.Axes.errorbar.html中的标记

fillstyle接受以下值:[‘full’| “左” | ‘正确’| “底部” | ‘顶部’| ‘没有’]

使用时有两点要牢记fillstyle

1)如果将mfc设置为任何类型的值,它将具有优先权,因此,如果您将fillstyle设置为“ none”,则它不会生效。因此,请避免同时使用mfc和fillstyle

2)您可能想要控制标记的边缘宽度(使用markeredgewidthmew),因为如果标记相对较小且边缘宽度较厚,则标记看起来会像已填充,即使没有。

以下是使用错误栏的示例:

myplot.errorbar(x=myXval, y=myYval, yerr=myYerrVal, fmt='o', fillstyle='none', ecolor='blue',  mec='blue')

In matplotlib 2.0 there is a parameter called fillstyle which allows better control on the way markers are filled. In my case I have used it with errorbars but it works for markers in general http://matplotlib.org/api/_as_gen/matplotlib.axes.Axes.errorbar.html

fillstyle accepts the following values: [‘full’ | ‘left’ | ‘right’ | ‘bottom’ | ‘top’ | ‘none’]

There are two important things to keep in mind when using fillstyle,

1) If mfc is set to any kind of value it will take priority, hence, if you did set fillstyle to ‘none’ it would not take effect. So avoid using mfc in conjuntion with fillstyle

2) You might want to control the marker edge width (using markeredgewidth or mew) because if the marker is relatively small and the edge width is thick, the markers will look like filled even though they are not.

Following is an example using errorbars:

myplot.errorbar(x=myXval, y=myYval, yerr=myYerrVal, fmt='o', fillstyle='none', ecolor='blue',  mec='blue')

回答 4

基于Gary Kerr的示例,如此处所建议可以使用以下代码创建与指定值相关的空圆:

import matplotlib.pyplot as plt 
import numpy as np 
from matplotlib.markers import MarkerStyle

x = np.random.randn(60) 
y = np.random.randn(60)
z = np.random.randn(60)

g=plt.scatter(x, y, s=80, c=z)
g.set_facecolor('none')
plt.colorbar()
plt.show()

Basend on the example of Gary Kerr and as proposed here one may create empty circles related to specified values with following code:

import matplotlib.pyplot as plt 
import numpy as np 
from matplotlib.markers import MarkerStyle

x = np.random.randn(60) 
y = np.random.randn(60)
z = np.random.randn(60)

g=plt.scatter(x, y, s=80, c=z)
g.set_facecolor('none')
plt.colorbar()
plt.show()

回答 5

因此,我假设您想突出显示符合特定条件的一些要点。您可以使用Prelude的命令对高亮点进行第二次散点图绘制,并用一个空圆进行第一次散点图绘制。确保s参数足够小,以使较大的空圆圈包围较小的填充圆。

另一个选择是不使用散点图,而使用circle / ellipse命令分别绘制补丁。这些位于matplotlib.patches中,是一些有关如何绘制圆形矩形等的示例代码。

So I assume you want to highlight some points that fit a certain criteria. You can use Prelude’s command to do a second scatter plot of the hightlighted points with an empty circle and a first call to plot all the points. Make sure the s paramter is sufficiently small for the larger empty circles to enclose the smaller filled ones.

The other option is to not use scatter and draw the patches individually using the circle/ellipse command. These are in matplotlib.patches, here is some sample code on how to draw circles rectangles etc.