from scipy.io import read_array
import numpy as np
import matplotlib.pyplot as plt

m = read_array("v.matrix")

x = np.reshape(m[:, 0], (51, 51))
y = np.reshape(m[:, 1], (51, 51))
z = np.reshape(m[:, 2], (51, 51))

plt.subplot(111, autoscale_on=False, xlim=(0, 50), ylim=(0, 50))

# plot contour lines with filling in between:
my_contour = plt.contourf(x, y, z)

# add a colorbar to the figure
plt.colorbar(my_contour)

plt.show()