如何在我的情节中获得传奇？

Question

How can I get a legend from the Elev_Avg component of polydatx ?

I tried using ax.legend() , but I got this error:

No handles with labels found to put in legend.

Plot

f, ax = plt.subplots(1, figsize=(8, 8))
polydatx.plot(ax = ax, column = 'Elev_Avg', cmap='OrRd', scheme='quantiles', label='elev')
segdatx.plot(ax = ax)
ax.grid(False)
ax.legend()

Answer 1

You have to tell the computer what to put in the legend. Then you will get it :)

For example, if what you are plotting are two columns ['s1', 's2'] from a pandas dataframe df, then this is what you would do to get the plot and legend:

ax.plot(df.loc[:,['s1', 's2']], marker='o')
ax.legend(['s1', 's2'])
plt.show()

Answer 2

According matplotlib document ( matplotlib ) the handles is optional, but for some reason most people get that error message. What I did was

handles, labels = ax.get_leggend_handles_labels()

ax.legend(handles, labels). It seems to work for me.