A colormap is a key ingredient to produce both readable and visually pleasing figures. However, we are doing science here, and esthetic is just a side objective. When using colormaps, we would like to know which value corresponds to a given color. In this recipe, we will look at a simple way to add such information to a figure.
We will use the same example, the Mandelbrot set. We simply add a call to pyplot.colorbar():
import numpy as np
from matplotlib import pyplot as plt
import matplotlib.cm as cm
def iter_count(C, max_iter):
X = C
for n in range(max_iter):
if abs(X) > 2.:
return n
X = X ** 2 + C
return max_iter
N = 512
max_iter = 64
xmin, xmax, ymin, ymax = -2.2, .8, -1.5, 1.5
X = np.linspace(xmin, xmax, N)
Y = np.linspace(ymin, ymax, N)
Z = np.empty((N, N))
for i, y in enumerate(Y):
for j, x in enumerate(X):
Z[i, j] = iter_count(complex(x, y), max_iter)
plt.imshow(Z,
cmap...