def getAngles(theta, r):
    x = r * np.cos(theta)
y = r * np.sin(theta)
dx = np.diff(x)
dy = np.diff(y)
normalY = -dx
normalX = dy
return np.degrees(np.arctan(normalY / normalX)) + 90
azel = np.asarray(azel)
theta = azel[:, (1)]
r = azel[:, (0)]
angles = getAngles(theta, r)
markers_on = [5, 10, 15, 20]
fig = figure()
ax = fig.add_subplot(1, 1, 1, projection='polar')
ax.plot(theta, r)
for i in markers_on:
    ax.plot(theta[i], r[i], marker=(2, 0, angles[i - 1]), mew=3, markersize=7)
ax.annotate('Point: %i' % i, xy=(theta[i], r[i]), xytext=(theta[i], r[i] + 
    2), horizontalalignment='left', verticalalignment='top')
ylim([0, 25])
show()
Добавление аннотации к точкам данных