I'm attempting to use fill_between in a radar plot to paint a "ring", following the matplotlib radar example here: https://matplotlib.org/3.1.0/gallery/specialty_plots/radar_chart.html
I left the radar_factory function untouched, except for an additional, overloaded function "fill_between", following the example of "fill" which is already present in the example:
def fill_between(self, *args, closed=True, **kwargs):
"""Override fill_between so that lines are closed by default"""
return super().fill_between(closed=closed, *args, **kwargs)
As far as I understand, this should pass closed=True to a PolyCollection object. It doesn't however.
Here's the code to reproduce the problem. It's a bit longer than minimal, but I think it's important to stay close to the example from the matplotlib documentation:
import numpy as np
import matplotlib.pyplot as plt
from matplotlib.patches import Circle, RegularPolygon
from matplotlib.path import Path
from matplotlib.projections.polar import PolarAxes
from matplotlib.projections import register_projection
from matplotlib.spines import Spine
from matplotlib.transforms import Affine2D
def radar_factory(num_vars, frame='circle'):
# calculate evenly-spaced axis angles
theta = np.linspace(0, 2*np.pi, num_vars, endpoint=False)
class RadarAxes(PolarAxes):
name = 'radar'
# use 1 line segment to connect specified points
RESOLUTION = 1
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
# rotate plot such that the first axis is at the top
self.set_theta_zero_location('N')
def fill(self, *args, closed=True, **kwargs):
"""Override fill so that line is closed by default"""
return super().fill(closed=closed, *args, **kwargs)
def fill_between(self, *args, closed=True, **kwargs):
"""
Override fill_between so that lines are closed by default
- CUSTOM ADDITION TO EXAMPLE -
"""
return super().fill_between(closed=closed, *args, **kwargs)
def plot(self, *args, **kwargs):
"""Override plot so that line is closed by default"""
lines = super().plot(*args, **kwargs)
for line in lines:
self._close_line(line)
def _close_line(self, line):
x, y = line.get_data()
# FIXME: markers at x[0], y[0] get doubled-up
if x[0] != x[-1]:
x = np.concatenate((x, [x[0]]))
y = np.concatenate((y, [y[0]]))
line.set_data(x, y)
def set_varlabels(self, labels):
self.set_thetagrids(np.degrees(theta), labels)
def _gen_axes_patch(self):
# The Axes patch must be centered at (0.5, 0.5) and of radius 0.5
# in axes coordinates.
if frame == 'circle':
return Circle((0.5, 0.5), 0.5)
elif frame == 'polygon':
return RegularPolygon((0.5, 0.5), num_vars,
radius=.5, edgecolor="k")
else:
raise ValueError("unknown value for 'frame': %s" % frame)
def _gen_axes_spines(self):
if frame == 'circle':
return super()._gen_axes_spines()
elif frame == 'polygon':
# spine_type must be 'left'/'right'/'top'/'bottom'/'circle'.
spine = Spine(axes=self,
spine_type='circle',
path=Path.unit_regular_polygon(num_vars))
# unit_regular_polygon gives a polygon of radius 1 centered at
# (0, 0) but we want a polygon of radius 0.5 centered at (0.5,
# 0.5) in axes coordinates.
spine.set_transform(Affine2D().scale(.5).translate(.5, .5)
+ self.transAxes)
return {'polar': spine}
else:
raise ValueError("unknown value for 'frame': %s" % frame)
register_projection(RadarAxes)
return theta
if __name__ == '__main__':
N = 5
theta = radar_factory(N, frame='polygon')
data1 = [2,1.5,3,3,2]
data2 = [1,0.5,2,2,1]
spoke_labels = ['A', 'B', 'C', 'D', 'E']
fig, ax = plt.subplots(figsize=(9, 9), nrows=1, ncols=1,
subplot_kw=dict(projection='radar'))
ax.plot(theta, data1, color='blue')
ax.plot(theta, data2, color='blue')
ax.fill_between(theta, y1=data1, y2=data2, color='red')
ax.fill(theta, data1, facecolor='blue', alpha=0.25)
ax.set_varlabels(spoke_labels)
plt.show()
And its output. I would expect the red area to follow the example of the blue area and fill the whole polygon.
How do I close the red gap?
