marketshare: Fictitional marketshare of five companies

In clauswilke/dviz.supp: Supporting materials for Claus Wilke's data visualization book

Description

Fictitional marketshare of five companies, made up to demonstrate how pie charts can be misleading.

Usage

marketshare

Format

An object of class data.frame with 15 rows and 3 columns.

References

Source: https://en.wikipedia.org/wiki/File:Piecharts.svg

Examples

library(dplyr)
library(ggplot2)
library(ggforce)
library(colorblindr)

# calculate the start and end angles for each pie
market_pie <- marketshare %>%
  group_by(year) %>%
  mutate(total = sum(percent),
         end_angle = 2*pi*cumsum(percent)/total,      # ending angle for each pie slice
         start_angle = lag(end_angle, default = 0),   # starting angle for each pie slice
         mid_angle = 0.5*(start_angle + end_angle),   # middle of each pie slice, for the text label
         hjust = ifelse(mid_angle>pi, 1, 0),
         vjust = ifelse(mid_angle<pi/2 | mid_angle>3*pi/2, 0, 1))

rpie = 1
rlabel = 1.05 * rpie

ggplot(market_pie) + 
  geom_arc_bar(aes(x0 = 0, y0 = 0, r0 = 0, r = rpie,
                   start = start_angle, end = end_angle, fill = company), color = NA) +
  geom_text(aes(x = rlabel*sin(mid_angle), y = rlabel*cos(mid_angle), label = company,
                hjust = hjust, vjust = vjust)) +
  coord_fixed() +
  facet_wrap(~year) +
  scale_x_continuous(limits = c(-1.2, 1.2), expand = c(0, 0), name = "", breaks = NULL, labels = NULL) +
  scale_y_continuous(limits = c(-1.2, 1.2), expand = c(0, 0),name = "", breaks = NULL, labels = NULL) +
  scale_fill_OkabeIto(order = c(1:3, 5, 4)) + 
  guides(fill = "none") +
  theme_void()

clauswilke/dviz.supp documentation built on Aug. 25, 2020, 2:12 a.m.