Compare matplotlib contour and tricontour for randomized grid

compare_mpl_contour.py

# Code was written in an answer to this Stackoverflow question:
# http://stackoverflow.com/questions/42045921/why-does-pyplot-contour-require-z-to-be-a-2d-array

import matplotlib.pyplot as plt
from matplotlib.widgets import Slider
import numpy as np

fig, (ax, ax2) = plt.subplots(ncols=2, figsize=(6,3.7) )
plt.subplots_adjust(left=0.05, right=0.95, bottom=0.05, top=0.82, wspace=0.07)
def setup():
    ax.clear()
    ax2.clear()
    ax.set_aspect("equal")
    ax2.set_aspect("equal")
    ax.set_xticks([])
    ax.set_yticks([])
    ax2.set_xticks([])
    ax2.set_yticks([])
    ax.set_title("contour")
    ax2.set_title("tricontour")

axgrid = fig.add_axes([0.37, 0.95, 0.32, 0.03], facecolor="w")
axrand = fig.add_axes([0.37, 0.9, 0.32, 0.03], facecolor="w")

sgrid = Slider(axgrid, 'Grid', 3, 30, valinit=16)
srand = Slider(axrand, 'rand', 0, 1., valinit=0)


def update(val):
    grid = int(sgrid.val)
    rand = srand.val
    setup()
    x = np.linspace(0,5,grid)
    y = np.linspace(0,5,grid)
    X,Y = np.meshgrid(x,y)
    Xr = np.random.rand(grid,grid)*5
    Yr = np.random.rand(grid,grid)*5
    X = (1-rand)*X + rand*Xr
    Y = (1-rand)*Y + rand*Yr
    Z = np.round(np.sin(X*1.1)*np.cos(Y*1.1), 2)

    ax.contour(X,Y,Z, 10)
    ax2.tricontour(X.ravel(),Y.ravel(),Z.ravel(), 10)
    fig.canvas.draw_idle()

update(0)
    
sgrid.on_changed(update)
srand.on_changed(update)

plt.show()

Creating the following matplotlib output