Parallel Coordinates Plotting Using Pandas

Overview:

  • Parallel coordinates is one of the oldest visualization techniques for understanding multivariate data.
  • In a parallel coordinates plot, variables are represented through vertical parallel lines. These lines form the axes for the plot.
  • Each data point of the multivariate data is marked in these vertical axes which result in a polyline.
  • One data point corresponds to one polyline. In case of multiple data points with the same values, a poly line is drawn multiple times, one over another.
  • The height of the vertical axes does not correspond to any order in the data.
  • The parallel axis of the parallel coordinates plot can be drawn horizontally as well.
  • The lines denoting the data point are typically not smooth as in case of Andrews Curves, which is another visualization technique that projects the multivariate data to a vector formed by the co-efficients of the finite Fourier series.

Example:

# Example Python program that creates
# a parallel coordinates plot using pandas
# plotting module
# Data Courtesy: https://archive.ics.uci.edu/ml/datasets/Breast+Tissue
import pandas as pds
import matplotlib.pyplot as plt

# Read data from a CSV file into a DataFrame
df = pds.read_csv("BreastTissue.csv");

# Use the DataFrame instance and draw the parallel coordinates plot
pds.plotting.parallel_coordinates(df, 'Class',
                                  color=('#c0392b', '#9b59b6', '#5499c7',
                                         '#1abc9c', '#f1c40f', '#f39c12'));

plt.show(block=True);

Output:

Parallel Coordinates plot using pandas for the BreastTissue dataset

 

 


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