Adding markers or lines to colorbar in matplotlib

Question

I have the following lines of code to generate a heatmap (pcolormesh).

import matplotlib.pyplot as plt
import numpy as np

vals = np.linspace(-np.pi/2, np.pi/2, 101)
x, y = np.meshgrid(vals, vals)

z = np.abs(np.sinc(x) * np.sinc(y))

xDeg = np.rad2deg(x)
yDeg = np.rad2deg(y)

plt.pcolormesh(xDeg, yDeg, z, cmap = 'jet', vmin = 0, vmax = 1)
plt.colorbar()

plt.axis([-90, 90, -90, 90])
ticks = np.linspace(-90, 90, 13)
plt.xticks(ticks)
plt.yticks(ticks)

print np.mean(z)                # 0.186225110029
print np.sqrt(np.mean(z**2))    # 0.295710882276
plt.show()

It produces this image:

I'd like to place:

1. A marker on the colorbar at the mean (0.186).
2. A horizontal line on the colorbar at the RMS value (0.295).

Any input?

Answer 1

That was easier than expected. I didn't realize colorbar has a plottable axis in plt.colorbar().ax

cb = plt.colorbar()
cb.ax.plot(0.5, mean, 'w.') # my data is between 0 and 1
cb.ax.plot([0, 1], [rms]*2, 'w') # my data is between 0 and 1
# Note: would need to scale mean/rms to be between 0 and 1

Looks like the x-axis is (0, 1) and y-axis (dataMin, dataMax) (0, 1).