CODEWITHSUNDEEP
pythonmatplotlibscatter-plotalpha
toomas
toomas

Reputation: 670

How to make pyplot scatter markers opaque?

I want to make a plot of lines with opaque scatter markers superimposed on them at certain points. But the lines keep shining through markers, even with alpha=1:

import matplotlib.pyplot as plt
plt.close('all')
plt.plot([0, 2], [0, 0], color='black')
plt.scatter([1], [0], color='red', alpha=1)
plt.savefig('/tmp/foo.png')

red marker not opaque at all

How to make the red marker really opaque, i.e. make the black line completely invisible beneath it?

Upvotes: 2

Views: 839

Answers (1)

JohanC
JohanC

Reputation: 80509

Your problem is the z-order of the elements. Default, lines will be drawn on top of markers. Use plt.scatter(..., zorder=3) to force the markers on top.

import matplotlib.pyplot as plt
plt.plot([0, 2], [0, 0], color='black')
plt.scatter([1], [0], color='red', alpha=1, zorder=3)
plt.show()

example plot

Upvotes: 4

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