Creating a color map from a list of RGB colors

Question

I want to create a color map in python similar to this image:

but my map only consists of 3 rows and 4 columns. And I want to assign a certain color value to each square using RGB values. I have tried this code

colors=np.array([[0.01, 0.08, 0.01], [0.01, 0.16, 0.01], [0.01, 0.165, 0.01], [0.01, 0.3, 0.01],
                 [0.01, 0.2, 0.01], [0.666, 0.333, 0.01], [0.01, 0.165, 0.01], [0.01, 0.3, 0.01],
                 [0.01, 0.2, 0.01], [0.666, 0.333, 0.01], [0.01, 0.165, 0.01], [0.01, 0.3, 0.01]])


fig, ax=plt.subplots()
ax.imshow(colors)
ax.set_aspect('equal')
plt.show()

but the output does not match my expectations. It seems that with this method I cannot use the RGB values to represent the color for a square. Can anyone help me, please? Thank you!

Answer 1

You have a (12,3) colors array, while you need a (4, 3, 3) image, one RGB color per pixel.

import numpy as np  # type: ignore
import matplotlib.pyplot as plt  # type: ignore

colors = np.array(
    [
        # this is the first row
        [
            # these are the 3 pixels in the first row
            [0.01, 0.08, 0.01],
            [0.01, 0.16, 0.01],
            [0.01, 0.165, 0.01],
        ],
        [
            [0.01, 0.3, 0.01],
            [0.01, 0.2, 0.01],
            [0.666, 0.333, 0.01],
        ],
        [
            [0.01, 0.165, 0.01],
            [0.01, 0.3, 0.01],
            [0.01, 0.2, 0.01],
        ],
        # this is the fourth row
        [
            [0.666, 0.333, 0.01],
            [0.01, 0.165, 0.01],
            [0.01, 0.3, 0.01],
        ],
    ]
)
print(colors.shape)


fig, ax = plt.subplots()
ax.imshow(colors)
ax.set_aspect("equal")
plt.show()

Rearrange the data as you need in rows/columns.