Circular chart customization for the circlize R package



This post follows the previous introduction to the circlize package. It shows how to apply basic customizations to a circular chart: how to change track width, background color, start angle and more.

Chord section Data to Viz

Most basic circular chart


Let’s remind how to build a basic circular chart with the circlize package.

This is extensively described in chart #224.

# Upload library
library(circlize)

# Create data
data = data.frame(
    factor = sample(letters[1:8], 1000, replace = TRUE),
    x = rnorm(1000),
    y = runif(1000)
    )

# Step1: Initialise the chart giving factor and x-axis.
circos.initialize( factors=data$factor, x=data$x )

# Step 2: Build the regions.
circos.trackPlotRegion(factors = data$factor, y = data$y, panel.fun = function(x, y) {
    circos.axis()
    })

# Step 3: Add points
circos.trackPoints(data$factor, data$x, data$y)

Customization


Customization can happen at 3 different levels:

  • initialization: use the usual par() function and the specific circos.par() functions for general stuff.
  • in circos.axis() to customize axis
  • in circos.trackPoints()` to customize the chart shapes.

Note that most of the parameters are consistent with base R. Have a look to the scatterplot section of the gallery for more customization.

# Upload library
library(circlize)

# Create data
data = data.frame(
    factor = sample(letters[1:8], 1000, replace = TRUE),
    x = rnorm(1000),
    y = runif(1000)
    )

# General Customization:
par(
  mar = c(1, 1, 1, 1),           # Margin around chart
  bg = rgb(0.4,0.1,0.7,0.05)     # background color
) 
circos.par("track.height" = 0.6) # track hight, 0.6 = 60% of total height

# Step1: Initialise the chart giving factor and x-axis.
circos.initialize( factors=data$factor, x=data$x )

# Step2: Build regions. 
circos.trackPlotRegion(factors = data$factor, y = data$y, panel.fun = function(x, y) {
    circos.axis(
        h="top",                   # x axis on the inner or outer part of the track?
        labels=TRUE,               # show the labels of the axis?
        major.tick=TRUE,           # show ticks?
        labels.cex=0.5,            # labels size (higher=bigger)
        labels.font=1,             # labels font (1, 2, 3 , 4)
        direction="outside",       # ticks point to the outside or inside of the circle ?
        minor.ticks=4,             # Number of minor (=small) ticks
        major.tick.percentage=0.1, # The size of the ticks in percentage of the track height
        lwd=2                      # thickness of ticks and x axis.
        )
    })

# Step 3: Add points
circos.trackPoints(data$factor, data$x, data$y, col = "#69b3a2", pch = 16, cex = 0.5)

Related chart types


Chord diagram
Network
Sankey
Arc diagram
Edge bundling



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 on Twitter, or send an email pasting yan.holtz.data with gmail.com.

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