2D Density Chart

This section explains how to build a 2d density chart or a 2d histogram with python. Those chart types allow to visualize the combined distribution of two quantitative variables. They can be build with `Matplotlib` or `Seaborn`.

💡 What is a 2D density chart?

There are several chart types allowing to visualize the distribution of a combination of 2 numeric variables. They always have a variable represented on the X axis, the other on the Y axis, like for a scatterplot (left).

Then the number of observations within a particular area of the 2D space is counted and represented with a color gradient. The shape can vary: hexagones result in a `hexbin chart`, squares in a `2d histogram`. A kernel density estimate can be used to get a `2d density plots` or a `contour plots`

Confusing? Visit data-to-viz to clarify..

Contour plot with `Seaborn`

The contour plot can be easily built thanks to the `kdeplot()` function of the Seaborn library.

2D histogram with `Seaborn`

Build a 2d histogram thanks to the `hist2d()` function of the `Seaborn` library. Do not forget to play with the `bins` argument to find the value representing the best your data.

Hexbin chart with `Matplotlib`

Split the graph area in hexagones and you get a hexbin density chart. This time, it is `matplotlib` that gets you covered thanks to its `hexbin()` function.

2d density chart with `Matplotlib`

2D densities are computed thanks to the `gaussian_kde()` function and plotted thanks with the `pcolormesh()` function of `matplotlib()`.

2d density and marginal plots

2D densities often combined with marginal distributions. It helps to highlight the distribution of both variables individually. It is pretty straightforward to add thanks to the `jointplot()` function of the `Seaborn` library.

Contact

👋 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