matplotlib ArtistAnimation shows only one frame

Question

I am trying to make an animation with matplotlib.animation, using the ArtistAnimation function. I have a large matrix and I want to show a different part of this matrix in a colormap using plt.imshow() in each frame. However, only one frame is shown in the animation and I don't know why. I tried to mimic the code in An animated image using a list of images. I have looked at this question and this question, but I could not find a solution there.

This is my code:

import matplotlib.pyplot as plt
import numpy as np
import matplotlib.animation as animation

def make_animation(pwv_matrix, length_side):
        pwv_shape = pwv_matrix.shape
        fig = plt.figure()
        num_frames = min(pwv_shape[0], pwv_shape[1])-length_side
        y_min = int(np.round(pwv_shape[0]/2) - np.round(length_side/2))
        y_max = int(np.round(pwv_shape[0]/2) + np.round(length_side/2))
        x_min = 0
        x_max = length_side
        ims = []
        for i in range(0, num_frames):
            pwv_frame = pwv_matrix[x_min:x_max, y_min:y_max]
            im = plt.imshow(pwv_frame, animated=True, cmap = 'viridis')
            ims.append([im])
            x_min += 1
            x_max += 1

        ani = animation.ArtistAnimation(fig, ims, interval=50, blit=True,
                                repeat_delay=1000)
        plt.show()

x = np.linspace(0, 1, 200)
y = np.linspace(0, 1, 200)
pwv_matrix, yv = np.meshgrid(x, y)
length_side = 20 #m
make_animation(pwv_matrix, length_side)

where self.pwv_matrix is a large matrix obtained from a .dat file. Does anyone see the problem?

Thanks very much in advance!

Check [mcve] and provide one in the question. – ImportanceOfBeingErnest Nov 19 '19 at 21:51 — ImportanceOfBeingErnest, Nov 19 '19 at 21:51
I now added everything to make the code able to run – Esmee Nov 20 '19 at 08:37 — Esmee, Nov 20 '19 at 08:37

score 0 · Accepted Answer · answered Nov 20 '19 at 08:50

0

Try adding a very small delay after the show() function with matplotlib.pyplot.pause(interval)[source] function or:

from time import sleep
sleep(0.05)

The actual drawing of the image occurs one you give it some processing time (in a very simplified way of explaining it)

If it does not work there are some other things you might try, let me know if it doesn't work

answered Nov 20 '19 at 08:50

Werner Thomassen Andrade

68
8

NP :] had the same issue once, glad to help – Werner Thomassen Andrade Nov 20 '19 at 09:10

matplotlib ArtistAnimation shows only one frame

1 Answers1