CODEWITHSUNDEEP
numpymatplotlibimshow
El Dude
El Dude

Reputation: 5618

how can i color specific pixels in matplotlib imshow?

I am plotting a numpy matrix with imshow and nearest neighbor interpolation in blue scale.

How can i color specific pixels in the plot so that they would be, say red?

pyplot.imshow(matrix, interpolation='nearest',cmap = cm.Blues)
pyplot.show()

Upvotes: 1

Views: 6775

Answers (1)

cphlewis
cphlewis

Reputation: 16249

You can't directly color pixels red with a colormap that doesn't have red in it. You could pick a red-blue colormap and norm your matrix data into the blue part, but you can also just plot over an imshow image:

from matplotlib import pyplot
from numpy.random import random
matrix = random((12,12))

from matplotlib import cm
pyplot.imshow(matrix, interpolation='nearest', cmap=cm.Blues)
pyplot.scatter([6,8], [10,7], color='red', s=40)
pyplot.show()

enter image description here

Upvotes: 5

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