Animating 2D Heat Map with Varying Time Intervals

[schniefen]

TL;DR Summary

how to animate 2d heat map

Consider the following heat map:

from scipy import special
import numpy as np
import matplotlib.pyplot as plt
 
u0=200
r0x=25
r0y=25
rmax=2.5
alpha=2
t=0.575
 
y, x = np.meshgrid(np.linspace(0, 50, 100), np.linspace(0, 50, 100))
r=np.sqrt((x-r0x)**2+(y-r0y)**2)
z=u0*(special.erf((rmax-r)/(4*alpha*t))-special.erf((-rmax-r)/(4*alpha*t)))
 
plt.pcolormesh(x, y, z, cmap='jet')
plt.xlim(x.min(), x.max())
plt.ylim(y.min(), y.max())
plt.xlabel('x')
plt.ylabel('y')
plt.title(f'Temperature at {t} unit time')
cbar=plt.colorbar()
cbar.set_label('Temperature')
plt.clim(0,200)

I would now like to animate this heat map for different t, say t=np.linspace(0.0001,3,200). My attempt so far is the following:

import numpy as np
from matplotlib import pyplot as plt
from matplotlib import animation
 
u0=200
r0x=25
r0y=25
rmax=2.5
alpha=2
 
def pulse_maker(x,y,t):
    x,y,t =np.meshgrid(x,y,t)
    r=np.sqrt((x-r0x)**2+(y-r0y)**2)
    return u0*(special.erf((rmax-r)/np.sqrt(4*alpha*t))-special.erf((-rmax-r)/np.sqrt(4*alpha*t)))
 
def plot_pulse(xvals, yvals, pulse, t, i):
    plt.clf()
    plt.title(f"Temperature at t = {t[I]:.2f}")
    plt.xlabel("x")
    plt.ylabel("y")
    plt.xlim(xvals.min(), xvals.max())
    plt.ylim(yvals.min(), yvals.max())
    plt.pcolormesh(xvals, yvals, pulse[I], cmap='jet')
    cbar=plt.colorbar()
    cbar.set_label('Temperature')
    plt.clim(0,200)
    return plt[/I][/I]
 
[I][I]def animate(i):
    plt = plot_pulse(xrange,yrange, pulse, times, i);[/I][/I]
 
[I][I]max_iterations = 200
times = np.linspace(0.0001, 3, max_iterations)
xrange = np.linspace(0,50, max_iterations)
yrange = np.linspace(0,50, max_iterations)
pulse = pulse_maker(x=xrange, y=yrange, t=times)
anim = animation.FuncAnimation(plt.figure(), animate, interval=1,
                               frames=max_iterations, repeat=False)
anim.save("heat.gif",writer='pillow')

However, there is something wrong with this animation if you run it. It does not give back the still image as above, rather the heat is very off-centered, although I have used the same initial values. Grateful for any feedback.

 

[Future Bruno]

The issue with your code is that you are recreating the plot each time with new data, rather than updating the plot with the new data. To update the plot with the new data, you need to create the plot once, and then update it in the animation loop. This can be done by creating a figure outside of the animation loop, and adding the plot to the figure in the animation loop.For example, try changing your code to this:import numpy as npfrom matplotlib import pyplot as pltfrom matplotlib import animation u0=200r0x=25r0y=25rmax=2.5alpha=2 def pulse_maker(x,y,t): x,y,t =np.meshgrid(x,y,t) r=np.sqrt((x-r0x)**2+(y-r0y)**2) return u0*(special.erf((rmax-r)/np.sqrt(4*alpha*t))-special.erf((-rmax-r)/np.sqrt(4*alpha*t))) def plot_pulse(xvals, yvals, pulse, t, i): plt.clf() plt.title(f"Temperature at t = {t:.2f}") plt.xlabel("x") plt.ylabel("y") plt.xlim(xvals.min(), xvals.max()) plt.ylim(yvals.min(), yvals.max()) plt.pcolormesh(xvals, yvals, pulse, cmap='jet') cbar=plt.colorbar() cbar.set_label('Temperature') plt.clim(0,200) return plt max_iterations = 200times = np.linspace(0.0001, 3, max_iterations)xrange = np.linspace(0,50, max_iterations)yrange = np.linspace(0,50, max_iterations)pulse = pulse