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pythonmatplotliblabelcontour

Labelling contour levels with personalized labels

I would like to label contour levels in a density plot, with personalized labels. I have written something like

contours = plt.contour(X, Y, Z, 3, colors='black')
plt.clabel(contours, inline=True, levels=[1,2], fontsize=8)

plt.imshow(Z, extent=[0, 5, 0, 5], origin='lower',
       cmap='RdGy', alpha=0.5)
plt.colorbar();

I would like that the contours are labelled by a name like r'\textbf{1-}'+r'$\sigma$'

Solution

  • What you're asking for is directly shown in the second example of the contour_label_demo. I will just quote that example here:

    ##################################################
# Label contours with arbitrary strings using a
# dictionary
##################################################
plt.figure()

# Basic contour plot
CS = plt.contour(X, Y, Z)

fmt = {}
strs = ['first', 'second', 'third', 'fourth', 'fifth', 'sixth', 'seventh']
for l, s in zip(CS.levels, strs):
    fmt[l] = s

# Label every other level using strings
plt.clabel(CS, CS.levels[::2], inline=True, fmt=fmt, fontsize=10)