Waffle chart for evolution



How to design a waffle chart for visualizing the chronological progression of various groups using R and ggplot2. It provides a reproducible code and an explanation of it.

Waffle section Data to Viz

About


The chart we want to reproduce is a waffle chart about the number of storms in the Atlantic Ocean.

It has been created by Muhammad Azhar. Thanks to him for accepting sharing his work here!

As a teaser, here’s the chart we want to reproduce:

Waffle Chart

Libraries


In order to create this chart, we will use the following libraries:

library(tidyverse)
library(showtext)
library(ggtext)
library(waffle)

Data


The data is the storms dataset, available when loading the tidyverse library. It contains information about storms in the Atlantic Ocean.

From this dataset, we will:

storms_df <- storms|> 
  filter(year >= 2010,
         status %in% c("hurricane", "tropical depression",
                       "tropical storm","tropical wave"))|> 
  count(year, status)

Then we define the fonts and the texts that will be used in the chart:

font_add_google("Outfit", "title_font")
font_add_google("Cabin", "body_font")
showtext_auto()

title_font <- "title_font"
body_font <- "body_font"

title_text <- "In the Atlantic Ocean, tropical storms are more common than other cyclones."
subtitle_text <- "Tropical Storm is a cyclone with maximum sustained winds of 39 to 73 mph (34 to 63 knots).\nshowing number of cyclones for each year since 2010"
caption_text <- "Graphic: Muhammad Azhar | #30DayChartChallenge | Data: NOAA"

Waffle chart for time series


Waffle chart can be used for various cases such distribution plot or time series.

In this case, we use it as a time series plot for displaying the number of storms, per year, with different statuses.

p = ggplot(storms_df, aes(fill = status, values = n)) +
  geom_waffle(color = "white", size = .25, n_rows = 10, flip = TRUE) +
  facet_wrap(~year, nrow = 1, strip.position = "bottom") +
  scale_x_discrete() + 
  scale_y_continuous(labels = function(x) x * 10, # make this multiplyer the same as n_rows
                     expand = c(0,0))+
  MetBrewer::scale_fill_met_d("Hiroshige", direction=1)+
  coord_equal()+
  labs(title = title_text,
       subtitle = subtitle_text,
       caption = caption_text)+
  theme_minimal()+
  theme(
    axis.title = element_blank(),
    axis.text.x = element_text(family = body_font, size=12),
    axis.text.y = element_text(family = body_font, size=12),
  # Legend
  legend.position = "top",
  legend.title = element_blank(),
  legend.spacing = unit(0.5, 'cm'),
  legend.key.height= unit(0.5, 'cm'),
  legend.key.width= unit(0.7, 'cm'),
  legend.text = element_text(family = body_font,
                             size=13,
                             face = 'plain',
                             color = "grey10"),
  
  # TITLE
  plot.title.position = "plot",
  plot.title = element_textbox(margin = margin(20, 0, 10, 0),
                               size = 30,
                               family = title_font,
                               face = "bold",
                               width = unit(55, "lines")),
  
  # SUB-TITLE
  plot.subtitle = element_text(margin = margin(10, 0, 20, 0),
                            size = 16,
                            family = body_font,
                            color = "grey15"),
  # Caption
  plot.caption = element_text(family=body_font,
                              face="plain",
                              size=14, 
                              color="grey40",
                              hjust=.5,
                              margin=margin(20,0,0,0)),
  
  plot.background = element_rect(color="white", fill="white"),
  plot.margin = margin(20, 40, 20, 40)
)

showtext_opts(dpi = 320)
ggsave(
  "img/graph/web-waffle-for-time-evolution.png",
  dpi=320, width = 12, height = 9
)
showtext_auto(FALSE)

Going further


This post explains how to create a waffle chart with nice features such as annotations, nice color theme and others, using R and ggplot2.

If you want to learn more, you can check the waffle section of the gallery and how to play with subgroups and colors in waffle charts.

Related chart types


Barplot
Spider / Radar
Wordcloud
Parallel
Lollipop
Circular Barplot



❤️ 10 best R tricks ❤️

👋 After crafting hundreds of R charts over 12 years, I've distilled my top 10 tips and tricks. Receive them via email! One insight per day for the next 10 days! 🔥