This post is an introduction to the circlize
package:
the ultimate way to build
circular charts with R. It shows
how to initialize a circular section and fill it with a
scatterplot.
In R, circular plots are made using the circlize
package.
Circular plots are composed by several regions (8 here), each
representing a level of a factor. Three steps are required to build a
circular plot:
Step 1: Initialize the chart with
circos.initialize()
. Provide the factor vector, and
the numeric values to use for the X axis. The circle will be
split in as many zone as the number of levels present in your
factor. Each region will be as long as the coresponding x axis.
Step2: Build the regions with
circos.trackPlotRegion()
. You have to specify the
factors once again, and tell what to use for the Y axis if
needed.
Step3: Add a chart in each region. Here
circos.trackPoints()
is used to build a
scatterplot. See
chart #226
for other chart types.
# 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, col = "blue", pch = 16, cex = 0.5)