Polar diagram with limit and abnormal points

Question

Consider the following data frame,

d = {'Score': [0.25, 0.52, 0.26, 0.22, 0.31, 2.45, 3.68, 41.3, 87, 91], 
     'Thr1': 16.5,
     'Thr2': 45.5,  
     'Anomaly':[0, 0, 0, 0, 0, 0, 0, 1, 1, 1]}

df = pd.DataFrame(data = d)

What I'm trying to do is build a polar diagram with a dashed line for threshold or multiple dashed lines for multiple thresholds and a different color for anomalies. What I still know

r = df['Score']
theta = df.index.values
fig = plt.figure()
ax = fig.add_subplot(111, projection = 'polar')
c = ax.scatter(theta, r)

I can’t get the threshold and change the color of the abnormal points. Any ideas?

Answer 1

You need to draw a dotted line at the threshold level to indicate where the threshold is. (the line appears as a circle on the polar graph).

Then you need to separate the values ​​up to the graph in the scatter plot, based on whether they are lower, between or above the threshold values, and color the dots accordingly.

import matplotlib
matplotlib.use('TkAgg')

import matplotlib.pyplot as plt
import pandas as pd
import numpy as np


dataset = {'Score': [0.25, 0.52, 0.26, 0.22, 0.31, 2.45, 3.68, 41.3, 87, 91], 
           'Thr1': 16.5,
           'Thr2': 45.5,  
           'Anomaly':[0, 0, 0, 0, 0, 0, 0, 1, 1, 1]}

df = pd.DataFrame(data=dataset)

scores = df['Score']
theta, thr_1, thr_2 = df.index.values, dataset['Thr1'], dataset['Thr2']

fig = plt.figure()
ax = fig.add_subplot(111, projection='polar')

# assigns a color to each point based on their relative value to the thresholds
colors = ['b' if val < thr_1 else 'y' if val < thr_2 else 'r' for val in scores]
point_cloud = ax.scatter(theta, scores, color=colors, marker='o')

# Drawing the threshold dash lines (with alpha value 1/2)
theta_xs, thr_y1, thr_y2 = np.linspace(0, 2*np.pi, 20), [thr_1] * 20, [thr_2] * 20
thr_line_1 = ax.plot(theta_xs, thr_y1, color='blue', linestyle='--', alpha=0.5)
thr_line_2 = ax.plot(theta_xs, thr_y2, color='green', linestyle='--', alpha=0.5)

plt.show()

Answer 2

, , , , Anomaly Score

import numpy as np
import pandas as pd
import matplotlib.pyplot as plt
import matplotlib.colors as c
d = {'Score': [0.25, 0.52, 0.26, 0.22, 0.31, 2.45, 3.68, 41.3, 87, 91],
     'Thr1': 16.5,
     'Thr2': 45.5,
     'Anomaly': [0, 0, 0, 0, 0, 0, 0, 1, 1, 1]}

df = pd.DataFrame(data = d)

r = df['Score']
theta = df.index.values
fig = plt.figure()
ax = fig.add_subplot(111, projection = 'polar')

#Add thresholds
ax.plot(np.linspace(0, 2*np.pi, 100), np.ones(100)*d['Thr1'], c='g', ls='--')
ax.plot(np.linspace(0, 2*np.pi, 100), np.ones(100)*d['Thr2'], c='r', ls='--')

#Add colors
colors = ['g' if v < d['Thr1'] else 'y' if v < d['Thr2'] else "r" for v in r]
sc = ax.scatter(theta, r, c=colors)

plt.show()