如何从我的 ax.pcolormesh() 密度图中删除矩形白色框？

Question

from mplsoccer.pitch import Pitch
import pandas as pd
import numpy as np
import matplotlib.pyplot as plt
from scipy.stats import kde

np.random.seed(19680801)
plt.style.use('dark_background')
fields = ['id', 'minute', 'result', 'X1', 'Y','xG','h_a','situation','season',
          'shotType','X']
df=pd.read_csv('shots.csv', skipinitialspace=True, usecols=fields)

df1 = pd.DataFrame({'A':df.Y,'B':df.X} )
a=(df1.to_numpy())
x, y = a.T
k = kde.gaussian_kde(a.T)

nbins=50

xi, yi = np.mgrid[x.min():x.max():nbins*1j, y.min():y.max():nbins*1j]
zi = k(np.vstack([xi.flatten(), yi.flatten()]))

pitch = Pitch(orientation='vertical',pitch_type='metricasports', view='half',
              linewidth=2, line_zorder=1,
              line_color= '#94A7AE',pitch_length=105, pitch_width=68,pad_bottom=0)

fig, ax = pitch.draw()
ax.pcolormesh(xi, yi, zi.reshape(xi.shape), shading='gouraud', cmap='Reds',facecolor='black'
              )

ax.set_xlim(ax.get_xlim()[::-1])       
ax.yaxis.tick_right()  
plt.axis('off')
plt.show()

Output Plot here

我想要唯一的红色密度图，而不是白色矩形背景框。如何让边框和我的背景一样？

Answer 1

这是一种使用 "under" color 为 'none' 的颜色图的方法。通过将 vmin 设置为 cut-off 值，具有较低值的单元格将获得“下方”颜色（'none' 代表完全透明）。要了解这些值，可以临时添加一个颜色条。这些值在很大程度上取决于 x 和 y 值的扩展（kde 的积分为 1，因此在一个小域上，值需要足够高）。

from mplsoccer.pitch import Pitch
import numpy as np
import matplotlib.pyplot as plt
from scipy.stats import kde
from copy import copy

np.random.seed(19680801)
plt.style.use('dark_background')
# first create some random toy data roughly mimicking the given plot
x = np.random.randn(100, 20).cumsum(axis=0).flatten()
y = np.random.randn(100, 20).cumsum(axis=0).flatten()
x = x * 0.04 + 0.5
y = y * 0.01 + 0.9
k = kde.gaussian_kde([x, y])

nbins = 50
xi, yi = np.mgrid[x.min():x.max():nbins * 1j, y.min():y.max():nbins * 1j]
zi = k(np.vstack([xi.flatten(), yi.flatten()]))

pitch = Pitch(orientation='vertical', pitch_type='metricasports', view='half',
              linewidth=2, line_zorder=1,
              line_color='#94A7AE', pitch_length=105, pitch_width=68, pad_bottom=0)

fig, ax = pitch.draw()
cmap = copy(plt.get_cmap('Reds'))
cmap.set_under('none')
pmesh = ax.pcolormesh(xi, yi, zi.reshape(xi.shape), shading='gouraud', cmap=cmap, vmin=5, facecolor='black')
# fig.colorbar(pmesh, ax=ax) # to temporarily get an idea of the values
ax.invert_xaxis()
ax.yaxis.tick_right()
plt.axis('off')
plt.show()

如何从我的 ax.pcolormesh() 密度图中删除矩形白色框？

How to remove the rectagular white colored frame from my ax.pcolormesh() density plot?

python

matplotlib

data-visualization

density-plot