'zorder' is not working properly in a windrose diagram

Question

I have set a higher zorder value for the bar plot compared to gridlines. But the gridlines are still visible over the bars. I have also tried for 'ax.set_axisbelow(True)' which is not working. Can anyone explain me how to solve the issue ?

from windrose import WindroseAxes
import pandas as pd
import matplotlib.pyplot as plt

# Sample data
data = {
    'WD (Deg)': [45, 90, 135, 180, 225, 270, 315, 0, 45],
    'WS (m/s)': [2, 3, 4, 5, 6, 7, 8, 9, 10]}

# Create a DataFrame
df = pd.DataFrame(data)

# Create a WindroseAxes object
ax = WindroseAxes.from_ax()

# Customize the grid
ax.grid(True, linestyle='--', linewidth=2.0, alpha=0.5,
        color='grey', zorder = 0)

# Set the axis below the wind rose bars
ax.set_axisbelow(True) ## Not working 

# Plot the wind rose bars
ax.bar(df['WD (Deg)'], df['WS (m/s)'], normed=True, opening=0.5, edgecolor='black',
       cmap=plt.cm.jet, zorder = 3)

plt.show()

I don't understand why is it happening. I want to plot the gridlines below the barplots. Thank in advance.

Answer 1

You can manually set the zorder of the patches, for example:

from windrose import WindroseAxes
import pandas as pd
import matplotlib.pyplot as plt

# Sample data
data = {
    'WD (Deg)': [45, 90, 135, 180, 225, 270, 315, 0, 45],
    'WS (m/s)': [2, 3, 4, 5, 6, 7, 8, 9, 10]}

# Create a DataFrame
df = pd.DataFrame(data)

# Create a WindroseAxes object
ax = WindroseAxes.from_ax()

# Customize the grid
ax.grid(True, linestyle='--', linewidth=2.0, alpha=0.5,
        color='grey', zorder=0)

# Set the axis below the wind rose bars
ax.set_axisbelow(True) ## Not working 

# Plot the wind rose bars
ax.bar(df['WD (Deg)'], df['WS (m/s)'], normed=True, opening=0.5, edgecolor='black',
       cmap=plt.cm.jet)


from matplotlib.patches import Rectangle

# get the minimum zorder of the patches
minzorder = min(
    [
        c.get_zorder() for c in ax.get_children() if isinstance(c, Rectangle)
    ]
)

# loop through rectangle patches and set zorder manually
# (keeping relative order of each rectangle and adding 3)
for child in ax.get_children():
    if isinstance(child, Rectangle):
        zorder = child.get_zorder()
        child.set_zorder(3 + (zorder - minzorder))

        # or just subtract ZBASE, e.g.
        # from windrose.windrose import ZBASE
        # child.set_zorder(3 + (zorder - ZBASE))

plt.show()