Stacked Line Plots

Stacked Line plots work in the same way traditional charts are rendered. However, they stack multiple data points together to show both size of difference and specific values. This type of chart is useful when you want to show the contribution of individual datasets to the total value at each point along the x-axis.

Here's a simple example of how to create a stacked line chart in Pygal

import pygal
import numpy as np 

np.random.seed(42)

# Number of categories
num_categories = 3

# Number of data points
num_points = 20

# Generate random data for each category
data = np.random.rand(num_categories, num_points) 

data

array([[0.37454012, 0.95071431, 0.73199394, 0.59865848, 0.15601864, 0.15599452, 0.05808361, 0.86617615, 0.60111501, 0.70807258, 0.02058449, 0.96990985, 0.83244264, 0.21233911, 0.18182497, 0.18340451, 0.30424224, 0.52475643, 0.43194502, 0.29122914], [0.61185289, 0.13949386, 0.29214465, 0.36636184, 0.45606998, 0.78517596, 0.19967378, 0.51423444, 0.59241457, 0.04645041, 0.60754485, 0.17052412, 0.06505159, 0.94888554, 0.96563203, 0.80839735, 0.30461377, 0.09767211, 0.68423303, 0.44015249], [0.12203823, 0.49517691, 0.03438852, 0.9093204 , 0.25877998, 0.66252228, 0.31171108, 0.52006802, 0.54671028, 0.18485446, 0.96958463, 0.77513282, 0.93949894, 0.89482735, 0.59789998, 0.92187424, 0.0884925 , 0.19598286, 0.04522729, 0.32533033]])

Stacked Line Plot fill=True

Adding the argument fill= True add color fill to the plots to make the contributions more easily readable.

line = pygal.StackedLine( fill=True )
line.title = "Sales Over Time (in millions)"

line.add('TV/Radio', data[0])
line.add('Website', data[1])
line.add('Stores', data[2])

line.render_in_browser()

Stacked Line Plot fill=False

Alternatively, fill= False generates a less involved plot.

line = pygal.StackedLine( fill=False)
line.title = "Sales Over Time (in millions)"

line.add('TV/Radio', data[0])
line.add('Website', data[1])
line.add('Stores', data[2])

line.render_in_browser()