如何完全消除散点图周围的空白? [英] How to completely remove the white space around a scatterplot?

问题描述

我正在尝试在图像上绘制散点图，而周围没有任何空白.

I am trying to plot a scatterplot over an image without having any white space around it.

如果仅按以下方式绘制图像，则没有空格:

If I plot just the image as follows, then there is no white space:

fig = plt.imshow(im,alpha=alpha,extent=(0,1,1,0))
plt.axis('off')
fig.axes.axis('tight')
fig.axes.get_xaxis().set_visible(False)
fig.axes.get_yaxis().set_visible(False)

但是当我在图像上添加散点图时，如下所示:

but as I add a scatter plot over the image as follows:

fig = plt.scatter(sx, sy,c="gray",s=4,linewidths=.2,alpha=.5)
fig.axes.axis('tight')
fig.axes.get_xaxis().set_visible(False)
fig.axes.get_yaxis().set_visible(False)

这时，通过使用以下savefig命令，将在图像周围添加空白:

At this point, by using the following savefig command, the white space is added around the image:

plt.savefig(im_filename,format="png",bbox_inches='tight',pad_inches=0)

关于绝对删除空白的任何想法吗?

Any idea on how to remove the white space definitely?

推荐答案

通过切换到mpl面向对象的样式，您可以在同一轴上绘制图像和散点图，因此只需设置空白一次，使用ax.imshow和ax.scatter.

By switching to the mpl object-oriented style, you can plot both the image and the scatter plot on the same axes, and hence only have to set the whitespace once, by using ax.imshow and ax.scatter.

在下面的示例中，我使用了 subplots_adjust 删除轴周围的空白，并ax.axis('tight')设置轴限制为数据范围.

In the example below, I've used subplots_adjust to remove the whitespace around the axes, and ax.axis('tight') to set the axis limits to the data range.

import matplotlib.pyplot as plt
import numpy as np

# Load an image
im = plt.imread('stinkbug.png')

# Set the alpha
alpha = 0.5

# Some random scatterpoint data
sx = np.random.rand(100)
sy = np.random.rand(100)

# Creare your figure and axes
fig,ax = plt.subplots(1)

# Set whitespace to 0
fig.subplots_adjust(left=0,right=1,bottom=0,top=1)

# Display the image
ax.imshow(im,alpha=alpha,extent=(0,1,1,0))

# Turn off axes and set axes limits
ax.axis('tight')
ax.axis('off')

# Plot the scatter points
ax.scatter(sx, sy,c="gray",s=4,linewidths=.2,alpha=.5)

plt.show()

这篇关于如何完全消除散点图周围的空白?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！