The polar coordinate system is most commonly used for pie charts, which are a stacked bar chart in polar coordinates.

coord_polar(theta = "x", start = 0, direction = 1, clip = "on")

## Arguments

theta variable to map angle to (x or y) offset of starting point from 12 o'clock in radians 1, clockwise; -1, anticlockwise Should drawing be clipped to the extent of the plot panel? A setting of "on" (the default) means yes, and a setting of "off" means no. For details, please see coord_cartesian().

## Examples

# NOTE: Use these plots with caution - polar coordinates has
# major perceptual problems.  The main point of these examples is
# to demonstrate how these common plots can be described in the
# grammar.  Use with EXTREME caution.

#' # A pie chart = stacked bar chart + polar coordinates
pie <- ggplot(mtcars, aes(x = factor(1), fill = factor(cyl))) +
geom_bar(width = 1)
pie + coord_polar(theta = "y") # A coxcomb plot = bar chart + polar coordinates
cxc <- ggplot(mtcars, aes(x = factor(cyl))) +
geom_bar(width = 1, colour = "black")
cxc + coord_polar() # A new type of plot?
cxc + coord_polar(theta = "y") # The bullseye chart
pie + coord_polar() df <- data.frame(
variable = c("does not resemble", "resembles"),
value = c(20, 80)
)
ggplot(df, aes(x = "", y = value, fill = variable)) +
geom_col(width = 1) +
scale_fill_manual(values = c("red", "yellow")) +
coord_polar("y", start = pi / 3) +
labs(title = "Pac man") # Windrose + doughnut plot
if (require("ggplot2movies")) {
movies$rrating <- cut_interval(movies$rating, length = 1)
movies$budgetq <- cut_number(movies$budget, 4)

doh <- ggplot(movies, aes(x = rrating, fill = budgetq))

# Wind rose
doh + geom_bar(width = 1) + coord_polar()
# Race track plot
doh + geom_bar(width = 0.9, position = "fill") + coord_polar(theta = "y")
}#> Loading required package: ggplot2movies 