# Network from Correlation Matrix

This post explains how to draw a correlation network: a network build on a correlation matrix.

Suppose that you have 10 individuals, and know how close they are related to each other. It is possible to represent these relationships in a network. Each individual will be a node. If 2 individuals are close enough (we set a threshold), then they are linked by an edge. That will show the structure of the population!

In this example, we see that our population is clearly split into 2 groups!

``````# libraries
import pandas as pd
import numpy as np
import networkx as nx
import matplotlib.pyplot as plt

# I build a data set: 10 individuals and 5 variables for each
ind1=[5,10,3,4,8,10,12,1,9,4]
ind5=[1,1,13,4,18,5,2,11,3,8]
df = pd.DataFrame({ 'A':ind1, 'B':ind1 + np.random.randint(10, size=(10)) , 'C':ind1 + np.random.randint(10, size=(10)) , 'D':ind1 + np.random.randint(5, size=(10)) , 'E':ind1 + np.random.randint(5, size=(10)), 'F':ind5, 'G':ind5 + np.random.randint(5, size=(10)) , 'H':ind5 + np.random.randint(5, size=(10)), 'I':ind5 + np.random.randint(5, size=(10)), 'J':ind5 + np.random.randint(5, size=(10))})

# Calculate the correlation between individuals. We have to transpose first, because the corr function calculate the pairwise correlations between columns.
corr = df.corr()

# Transform it in a links data frame (3 columns only):

# Keep only correlation over a threshold and remove self correlation (cor(A,A)=1)

# Plot the network:
nx.draw(G, with_labels=True, node_color='orange', node_size=400, edge_color='black', linewidths=1, font_size=15)``````

Chord Diagram

Network

Sankey

Arc Diagram

Edge Bundling

## Contact & Edit

👋 This document is a work by Yan Holtz. Any feedback is highly encouraged. You can fill an issue on Github, drop me a message onTwitter, or send an email pasting `yan.holtz.data` with `gmail.com`.

Violin

Density

Histogram

Boxplot

Ridgeline

Scatterplot

Heatmap

Correlogram

Bubble

Connected Scatter

2D Density

Barplot

Wordcloud

Parallel

Lollipop

Circular Barplot

Treemap

Venn Diagram

Donut

Pie Chart

Dendrogram

Circular Packing

Line chart

Area chart

Stacked Area

Streamgraph

Timeseries

Map

Choropleth

Hexbin

Cartogram

Connection

Bubble

Chord Diagram

Network

Sankey

Arc Diagram

Edge Bundling

Colors

Interactivity

Animation

Cheat sheets

Caveats

3D