A 'ggplot2' geom to draw a treemap.

A treemap is a rectangular plot divided into tiles, each of which represents a single observation. The relative area of each tile expresses a continuous variable.

geom_treemap(
  mapping = NULL,
  data = NULL,
  stat = "identity",
  position = "identity",
  na.rm = FALSE,
  show.legend = NA,
  inherit.aes = TRUE,
  fixed = NULL,
  layout = "squarified",
  start = "bottomleft",
  radius = grid::unit(0, "pt"),
  ...
)

Arguments

mapping, data, stat, position, na.rm, show.legend, inherit.aes, ...	Standard geom arguments as for `ggplot2::geom_rect()`.
fixed	Deprecated. Use `layout = "fixed"` instead. Will be removed in later versions.
layout	The layout algorithm, one of either 'squarified' (the default), 'scol', 'srow' or 'fixed'. See Details for full details on the different layout algorithms.
start	The corner in which to start placing the tiles. One of 'bottomleft' (the default), 'topleft', 'topright' or 'bottomright'.
radius	corner radius (default 0pt)

Details

geom_treemap() requires an area aesthetic. It will ignore any aesthetics relating to the x and y axes (e.g. xmin or y), as the x and y axes are not meaningful in a treemap. Several other standard 'ggplot2' aesthetics are supported (see Aesthetics). To add text labels to tiles, see geom_treemap_text().

An optional subgroup aesthetic will cause the tiles to be clustered in subgroups within the treemap. See geom_treemap_subgroup_border() and geom_treemap_subgroup_text() to draw borders around subgroups and label them, respectively. Up to three nested levels of subgrouping are supported, with subgroup2 and subgroup3 aesthetics and respective geom_treemap_subgroup2_border() etc. geoms.

Four layout algorithms are provided. With the default 'squarified' algorithm (layout = "squarified"), the priority is ensuring the tiles have an aesthetically pleasing aspect ratio; that is, they are not too narrow or too short. In this algorithm, tile placement proceeds from one corner, placing the tiles in either rows or columns until all the tiles are placed. See Bruls et al. (1999) for the full algorithm.

There are two variants on the 'squarified' algorithm. 'scol' forces tile placement to begin with a column, regardless of the effect on aspect ratio; 'srow' forces tile placement to been with a row. This will also apply to all subgroups. After the first row or column, the remaining tiles will be placed so as to optimise aspect ratios, as with the default algorithm.

With the 'fixed' layout algorithm (layout = "fixed"), the plot area is divided into vertical columns, which are each filled with an equal number of tiles beginning at the starting corner. Unlike the 'squarified' algorithm, with the 'fixed' algorithm the relative positions of the tiles are fixed by their order in the input data frame. This can result in aesthetically unpleasing layouts, but it allows side-by-side comparisons or animations to be created.

All 'treemapify' geoms added to a plot should have the same value for layout and start, or they will not share a common layout.

Aesthetics

area (required)
alpha
colour
fill
linetype
subgroup
subgroup2
subgroup3

References

Bruls, M., Huizing, K., & van Wijk, J. (1999). Squarified Treemaps (pp. 33-42). Proceedings of the Joint Eurographics and IEEE TCVG Symposium on Visualization. http://www.win.tue.nl/~vanwijk/stm.pdf

Author

David Wilkins (david@wilkox.org)

Bob Rudis (bob@rud.is)

Examples


ggplot2::ggplot(G20, ggplot2::aes(area = gdp_mil_usd, fill = region)) +
 geom_treemap()