• Install
• Example
• Animated treemaps
• Credit

Treemapify provides ggplot2 geoms for drawing treemaps

Install

Install ggplot2, reshape2, plyr, devtools and ggfittext if you don't have them already. ggfittext and treemapify are installed from github.

install.packages("ggplot2")
install.packages("reshape2")
install.packages("plyr")
install.packages("devtools")
library(devtools)
install_github("wilkox/ggfittext")
install_github("wilkox/treemapify")

Example

For this example, we'll plot some data on the G-20 group of major world economies. treemapify includes this in the G20 data frame:

library(ggplot2)
library(treemapify)
G20

A treemap has a tile for each observation, with the area of the tile proportional to a variable. Let's start by drawing a treemap with each tile representing a G-20 country. The area of the tile will be mapped to the country's GDP, and the tile's fill colour mapped to its HDI (Human Development Index). geom_treemap is the basic geom for this purpose.

ggplot(G20, aes(area = GDP.mil.USD, fill = HDI)) +
  geom_treemap()

This plot isn't very useful without the knowing what country is represented by each tile. geom_treemap_text can be used to add a text label to each tile. It uses the ggfittext package to resize the text so it fits the tile. In addition to standard text formatting aesthetics you would use in geom_text, like ‘fontface’ or ‘colour’, we can pass additional options specific for ggfittext. For example, we can place the text in the centre of the tile with place = "centre", and expand it to fill as much of the tile as possible with grow = TRUE.

ggplot(G20, aes(area = GDP.mil.USD, fill = HDI, label = Country)) +
  geom_treemap() +
  geom_treemap_text(
    fontface = "italic",
    colour = "white",
    place = "centre",
    grow = TRUE
  )

geom_treemap supports subgrouping of tiles within a treemap by passing a ‘subgroup’ aesthetic. Let's subgroup the countries by region, draw a border around each subgroup with geom_treemap_subgroup_border, and label each subgroup with geom_treemap_subgroup_text. As with geom_treemap_text, geom_treemap_subgroup_text can take ggfittext parameters for text placement and sizing.

ggplot(G20, aes(
  area = GDP.mil.USD,
  fill = HDI,
  label = Country,
  subgroup = Region,
  )) +
  geom_treemap() +
  geom_treemap_subgroup_border() +
  geom_treemap_subgroup_text(
    place = "centre",
    grow = T,
    alpha = 0.5,
    colour = "black",
    fontface = "italic",
    min.size = 0
  ) +
  geom_treemap_text(
    colour = "white",
    place = "topleft",
    reflow = T
  )

Note that ‘Argentina’ has been hidden. geom_treemap_text will hide text labels that cannot fit a tile without being shrunk below a minimum size, by default 4 points. This can be adjusted with the ‘min.size’ option.

Like any ggplot2 plot, treemapify plots can be faceted, scaled, themed, etc.

ggplot(G20, aes(area = GDP.mil.USD, fill = Region, label = Country)) +
  geom_treemap() +
  geom_treemap_text(grow = T, reflow = T, colour = "black") +
  facet_wrap( ~ Econ.classification) +
  scale_fill_brewer(palette = "Set1") +
  theme(legend.position = "bottom") +
  labs(
    title = "The G-20 major economies",
    caption = "The area of each country is proportional to its relative GDP
               within the economic group (advanced or developing)",
    fill = "Region"
  )

Animated treemaps

All the treemapify treemaps support a ‘fixed’ option that will cause the tiles to be laid out in an order determined by the order of observations in the data frame. While this can result in a less aesthetically pleasing and readable treemap, it allows you to create animated treemaps with the help of the tweenr and gganimate packages.

library(tweenr)
library(gganimate)

G20_alt <- G20
G20_alt$GDP.mil.USD <- sample(G20$GDP.mil.USD, nrow(G20))
G20_alt$HDI <- sample(G20$HDI, nrow(G20))

tweened <- tween_states(list(G20, G20_alt, G20), tweenlength = 15, statelength = 5, ease = 'cubic-in-out', nframes = 55)

animated_plot <- ggplot(tweened, aes(
  area = GDP.mil.USD,
  fill = HDI,
  label = Country,
  subgroup = Region,
  frame = .frame
  )) +
  geom_treemap(fixed = T) +
  geom_treemap_subgroup_border(fixed = T) +
  geom_treemap_subgroup_text(
    place = "centre",
    grow = T,
    alpha = 0.5,
    colour = "black",
    fontface = "italic",
    min.size = 0,
    fixed = T
  ) +
  geom_treemap_text(
    colour = "white",
    place = "topleft",
    reflow = T,
    fixed = T
  )

animation::ani.options(interval = 1/15)
gganimate(animated_plot, "man/figures/animated_treemap.gif", title_frame = F, ani.width = 400, ani.height = 400)

Credit

treemapify uses the Squarified Treemap algorithm of Mark Bruls, Kees Huizing and Jarke van Wijk.

The G20 dataset is from the Wikipedia article G-20 major economies, which is released under the Creative Commons Attribution-Share-Alike License 3.0.