Animating a Quadmesh from pcolormesh with matplotlib

Question

As a result of a full day of trial and error, I'm posting my findings as a help to anyone else who may come across this problem. For the last couple days, I've been trying to simulate a real-time plot of some radar data from a netCDF file to work with a GUI I'm building for a school project. The first thing I tried was a simple redrawing of the data using the 'interactive mode' of matplotlib, as follows: ``` import matplotlib.pylab as plt fig = plt.figure() plt.ion() #Interactive mode on for i in range(2,155): #Set to the number of rows in your quadmesh, start at 2 for overlap plt.hold(True) print i #Please note: To use this example you must compute X, Y, and C previously. #Here I take a slice of the data I'm plotting - if this were a real-time #plot, you would insert the new data to be plotted here. temp = plt.pcolormesh(X[i-2:i], Y[i-2:i], C[i-2:i]) plt.draw() plt.pause(.001) #You must use plt.pause or the figure will freeze plt.hold(False) plt.ioff() #Interactive mode off ``` While…

Accepted Answer

So I started looking into the matplotlib animation API, hoping to find a solution. The animation did turn out to be exactly what I was looking for, although its use with a QuadMesh object in slices was not exactly documented. This is what I eventually came up with:

```
import matplotlib.pylab as plt
from matplotlib import animation

fig = plt.figure()

plt.hold(True)
#We need to prime the pump, so to speak and create a quadmesh for plt to work with
plt.pcolormesh(X[0:1], Y[0:1], C[0:1])

anim = animation.FuncAnimation(fig, animate, frames = range(2,155), blit = False)

plt.show()
plt.hold(False)

def animate( self, i):
    plt.title('Ray: %.2f'%i)
    #This is where new data is inserted into the plot.
    plt.pcolormesh(X[i-2:i], Y[i-2:i], C[i-2:i])
```

Note that blit must be False! Otherwise it will yell at you about a QuadMesh object not being 'iterable'.

I don't have access to the radar yet, so I haven't been able to test this against live data streams, but for a static file, it has worked great thus far. While the data is being plotted, I can zoom and pan with the animation.

Good luck with your own animation/plotting ambitions!

Animating a Quadmesh from pcolormesh with matplotlib

Solution

Problem