Matplotlib散点图-删除白色填充 [英] Matplotlib scatter plot - Remove white padding

问题描述

我正在使用matplotlib在纬度经度坐标中绘制一个变量.问题是该图像不能包含轴或边界.我已经能够移除轴，但是必须完全移除图像周围的白色填充(请参见下面的代码示例图像:

I'm working with matplotlib to plot a variable in latitude longitude coordinates. The problem is that this image cannot include axes or borders. I have been able to remove axis, but the white padding around my image has to be completely removed (see example images from code below here: http://imgur.com/a/W0vy9) .

我尝试了Google搜索中的几种方法，包括以下StackOverflow方法:

I have tried several methods from Google searches, including these StackOverflow methodologies:

从matplotlib绘图中删除填充

如何在matplotlib中删除填充/边界子图(已解决)

Matplotlib图:删除轴，图例和空白

，但是删除空白没有任何作用.如果您有任何建议(即使是放弃matplotlib并尝试使用另一个绘图库)，我也将不胜感激！

but nothing has worked in removing the white space. If you have any advice (even if it is to ditch matplotlib and to try another plotting library instead) I would appreciate it!

这是我正在使用的代码的基本形式，它显示了这种行为:

Here is a basic form of the code I'm using that shows this behavior:

import numpy as np
import matplotlib
from mpl_toolkits.basemap import Basemap
from scipy import stats

lat = np.random.randint(-60.5, high=60.5, size=257087)
lon = np.random.randint(-179.95, high=180, size=257087)
maxnsz =  np.random.randint(12, 60, size=257087)

percRange = np.arange(100,40,-1)
percStr=percRange.astype(str)
val_percentile=np.percentile(maxnsz, percRange, interpolation='nearest')  

#Rank all values
all_percentiles=stats.rankdata(maxnsz)/len(maxnsz)
#Figure setup
fig = matplotlib.pyplot.figure(frameon=False, dpi=600)
#Basemap code can go here

x=lon
y=lat

cmap = matplotlib.cm.get_cmap('cool')


h=np.where(all_percentiles >= 0.999)
hl=np.where((all_percentiles < 0.999) & (all_percentiles > 0.90))
mh=np.where((all_percentiles > 0.75) & (all_percentiles < 0.90))
ml=np.where((all_percentiles >= 0.4) & (all_percentiles < 0.75))
l=np.where(all_percentiles < 0.4)

all_percentiles[h]=0
all_percentiles[hl]=0.25
all_percentiles[mh]=0.5
all_percentiles[ml]=0.75
all_percentiles[l]=1

rgba_low=cmap(1)
rgba_ml=cmap(0.75)
rgba_mh=cmap(0.51)
rgba_hl=cmap(0.25)
rgba_high=cmap(0)

matplotlib.pyplot.axis('off')

matplotlib.pyplot.scatter(x[ml],y[ml], c=rgba_ml, s=3, marker=',',edgecolor='none', alpha=0.4)
matplotlib.pyplot.scatter(x[mh],y[mh], c=rgba_mh, s=3,     marker='o', edgecolor='none', alpha=0.5)
matplotlib.pyplot.scatter(x[hl],y[hl], c=rgba_hl, s=4, marker='*',edgecolor='none', alpha=0.6)
matplotlib.pyplot.scatter(x[h],y[h], c=rgba_high, s=5, marker='^', edgecolor='none',alpha=0.75)

fig.savefig('/home/usr/code/python/testfig.jpg', bbox_inches=0, nbins=0, transparent="True", pad_inches=0.0)
fig.canvas.draw()

推荐答案

问题在于，所有解决方案都位于

The problem is that all the solutions given at Matplotlib plots: removing axis, legends and white spaces are actually meant to work with imshow.

因此，以下内容显然可行

So, the following clearly works

import matplotlib.pyplot as plt

fig = plt.figure()
ax=fig.add_axes([0,0,1,1])
ax.set_axis_off()

im = ax.imshow([[2,3,4,1], [2,4,4,2]], origin="lower", extent=[1,4,2,8])
ax.plot([1,2,3,4], [2,3,4,8], lw=5)

ax.set_aspect('auto')
plt.show()

产生

但是在这里，您正在使用scatter.添加散点图

But here, you are using scatter. Adding a scatter plot

import matplotlib.pyplot as plt

fig = plt.figure()
ax=fig.add_axes([0,0,1,1])
ax.set_axis_off()


im = ax.imshow([[2,3,4,1], [2,4,4,2]], origin="lower", extent=[1,4,2,8])
ax.plot([1,2,3,4], [2,3,4,8], lw=5)

ax.scatter([2,3,4,1], [2,3,4,8], c="r", s=2500)

ax.set_aspect('auto')
plt.show()

产生

Scatter具有默认情况下matplotlib尝试使所有点可见的特殊性，这意味着已设置轴限制，以使所有分散点在整体上可见.

Scatter has the particularity that matplotlib tries to make all points visible by default, which means that the axes limits are set such that all scatter points are visible as a whole.

要克服这一点，我们需要专门设置轴限制:

To overcome this, we need to specifically set the axes limits:

import matplotlib.pyplot as plt

fig = plt.figure()
ax=fig.add_axes([0,0,1,1])
ax.set_axis_off()

im = ax.imshow([[2,3,4,1], [2,4,4,2]], origin="lower", extent=[1,4,2,8])
ax.plot([1,2,3,4], [2,3,4,8], lw=5)

ax.scatter([2,3,4,1], [2,3,4,8], c="r", s=2500)

ax.set_xlim([1,4])
ax.set_ylim([2,8])

ax.set_aspect('auto')
plt.show()

这样我们就可以得到想要的行为.

such that we will get the desired behaviour.

这篇关于Matplotlib散点图-删除白色填充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！