Pictograms

geom_pictogram() draws a value as a grid of repeated icons, some fraction of them filled in and the rest left faded. The same geom produces a single-row rating widget, a waffle/percentage chart, or a growing isotype-style unit chart, depending on the grid arguments (n/nrow/ncol/symbol_value) passed to stat_pictogram().

Usage

geom_pictogram(
  mapping = NULL,
  data = NULL,
  stat = "pictogram",
  position = "identity",
  ...,
  n = NULL,
  nrow = NULL,
  ncol = NULL,
  symbol_value = NULL,
  n_target = 20,
  flow = "row",
  size.unit = "mm",
  spacing = 0.2,
  hjust = NULL,
  vjust = NULL,
  empty.colour = "grey85",
  empty.alpha = NULL,
  na.rm = FALSE,
  show.legend = NA,
  inherit.aes = TRUE
)

Arguments

mapping

Set of aesthetic mappings created by aes(). If specified and inherit.aes = TRUE (the default), it is combined with the default mapping at the top level of the plot. You must supply mapping if there is no plot mapping.

data

The data to be displayed in this layer. There are three options:

If NULL, the default, the data is inherited from the plot data as specified in the call to ggplot().

A data.frame, or other object, will override the plot data. All objects will be fortified to produce a data frame. See fortify() for which variables will be created.

A function will be called with a single argument, the plot data. The return value must be a data.frame, and will be used as the layer data. A function can be created from a formula (e.g. ~ head(.x, 10)).

stat

The statistical transformation to use on the data for this layer. When using a geom_*() function to construct a layer, the stat argument can be used to override the default coupling between geoms and stats. The stat argument accepts the following:

A Stat ggproto subclass, for example StatCount.
A string naming the stat. To give the stat as a string, strip the function name of the stat_ prefix. For example, to use stat_count(), give the stat as "count".
For more information and other ways to specify the stat, see the layer stat documentation.

position

A position adjustment to use on the data for this layer. This can be used in various ways, including to prevent overplotting and improving the display. The position argument accepts the following:

The result of calling a position function, such as position_jitter(). This method allows for passing extra arguments to the position.
A string naming the position adjustment. To give the position as a string, strip the function name of the position_ prefix. For example, to use position_jitter(), give the position as "jitter".
For more information and other ways to specify the position, see the layer position documentation.

...

Other arguments passed on to layer()'s params argument. These arguments broadly fall into one of 4 categories below. Notably, further arguments to the position argument, or aesthetics that are required can not be passed through .... Unknown arguments that are not part of the 4 categories below are ignored.

Static aesthetics that are not mapped to a scale, but are at a fixed value and apply to the layer as a whole. For example, colour = "red" or linewidth = 3. The geom's documentation has an Aesthetics section that lists the available options. The 'required' aesthetics cannot be passed on to the params. Please note that while passing unmapped aesthetics as vectors is technically possible, the order and required length is not guaranteed to be parallel to the input data.
When constructing a layer using a stat_*() function, the ... argument can be used to pass on parameters to the geom part of the layer. An example of this is stat_density(geom = "area", outline.type = "both"). The geom's documentation lists which parameters it can accept.
Inversely, when constructing a layer using a geom_*() function, the ... argument can be used to pass on parameters to the stat part of the layer. An example of this is geom_area(stat = "density", adjust = 0.5). The stat's documentation lists which parameters it can accept.
The key_glyph argument of layer() may also be passed on through .... This can be one of the functions described as key glyphs, to change the display of the layer in the legend.

n

Total slots in the grid (fixed-grid mode). NULL (the default) grows the grid to fit value instead.

nrow, ncol

Grid shape. Set at most one; the other is derived to wrap the slots. Both NULL wraps to a single row/column; see Orientation for which.

symbol_value

The data value one slot represents. NULL (the default) picks one automatically: 1 in fixed-grid mode (value is already a slot count, e.g. a percentage out of n = 100), or, in growing mode, the smallest "nice" round number (1, 2 or 5 times a power of ten) that keeps the layer's largest value to around n_target icons; see that argument. Set explicitly to turn auto-picking off.

n_target

In growing mode, roughly how many icons deep the growing dimension should get for the layer's largest value, when symbol_value is picked automatically. Turn this up for a finer-grained chart (more, smaller icons), down for a coarser one (fewer, bigger icons). Ignored if symbol_value is set explicitly, or in fixed-grid mode.

flow

Fill order: "row" (default) fills left-to-right then wraps to the next row; "col" fills top-to-bottom then wraps to the next column.

size.unit

The unit size is interpreted in, as in geom_icon(). Left at its default (NA), size instead auto-fits: each pictogram grows or shrinks to fill its own share of the panel, the way geom_bar() derives bar width. Set size to a number to opt out to a fixed physical size.

spacing

Gap between adjacent icons, as a fraction of size.

hjust, vjust

Where the grid sits relative to (x, y), as a fraction of its width/height: 0.5 centres it, 0/1 anchor an edge. Usually left at the default (NULL), which follows stat_pictogram()'s orientation: centred on an axis you mapped, anchored to the panel edge on one you left unmapped. So leaving y out of aes() draws a column chart growing up from the bottom, and leaving x out draws a bar growing from the left.

empty.colour, empty.alpha

Colour and alpha for empty slots. empty.alpha defaults to the alpha aesthetic.

na.rm

If FALSE, the default, missing values are removed with a warning. If TRUE, missing values are silently removed.

show.legend

logical. Should this layer be included in the legends? NA, the default, includes if any aesthetics are mapped. FALSE never includes, and TRUE always includes. It can also be a named logical vector to finely select the aesthetics to display. To include legend keys for all levels, even when no data exists, use TRUE. If NA, all levels are shown in legend, but unobserved levels are omitted.

inherit.aes

If FALSE, overrides the default aesthetics, rather than combining with them. This is most useful for helper functions that define both data and aesthetics and shouldn't inherit behaviour from the default plot specification, e.g. annotation_borders().

Value

A ggplot2 layer.

Aesthetics

geom_pictogram() understands the following aesthetics (value and icon are required):

x, y: the grid's anchor position. Leaving one out draws a bar/column chart instead of a fixed-position grid; see stat_pictogram()'s Orientation section.
value: the magnitude a pictogram represents. stat_pictogram() turns it into a filled slot count using symbol_value, the amount one icon stands for. Also drives an automatic guide_pictogram() legend spelling that ratio out; turn it off with guides(value = "none").
icon: the icon drawn in every slot, filled or empty (as in geom_icon()).
colour/fill: the filled-slot colour; empty slots use empty.colour instead.
alpha, angle, size: as in geom_icon().

geom_pictogram() understands the following aesthetics. Required aesthetics are displayed in bold and defaults are displayed for optional aesthetics:

•	`value`
•	`icon`
•	`alpha`	→ `NA`
•	`angle`	→ `0`
•	`colour`	→ `"black"`
•	`fill`	→ `NA`
•	`group`	→ inferred
•	`size`	→ `NA`

Learn more about setting these aesthetics in vignette("ggplot2-specs").

Examples

library(ggplot2)

# bundled placeholder shapes; a real pack (e.g. icons::fontawesome) works the same
shapes <- icons::icon_set(system.file("icons", package = "ggicons"))

# 10x10 waffle: 37%
ggplot(NULL, aes(x = "Proportion", value = 37)) +
  geom_pictogram(icon = shapes$square, n = 100, nrow = 10)
#> Error in geom_pictogram(icon = shapes$square, n = 100, nrow = 10): Problem while converting geom to grob.
#> ℹ Error occurred in the 1st layer.
#> Caused by error in `loadNamespace()`:
#> ! there is no package called ‘grImport2’

# single-row rating: 5 slots, 3 filled, legend switched off
ggplot(NULL, aes(y = "Rating", value = 3)) +
  geom_pictogram(icon = shapes$star, n = 5, colour = "goldenrod") +
  guides(value = "none")
#> Error in geom_pictogram(icon = shapes$star, n = 5, colour = "goldenrod"): Problem while converting geom to grob.
#> ℹ Error occurred in the 1st layer.
#> Caused by error in `loadNamespace()`:
#> ! there is no package called ‘grImport2’

# growing isotype chart: two categories, each sized to its own value
pets <- data.frame(animal = c("Cat", "Dog"), count = c(23, 15))
ggplot(pets, aes(animal, y = "Pet", value = count, icon = animal, colour = animal)) +
  geom_pictogram(nrow = 5) +
  scale_icon_manual(values = c(icons::fontawesome$solid$cat, icons::fontawesome$solid$dog))
#> Error in geom_pictogram(nrow = 5): Problem while converting geom to grob.
#> ℹ Error occurred in the 1st layer.
#> Caused by error in `loadNamespace()`:
#> ! there is no package called ‘grImport2’
# column chart: no y aesthetic, so icons fill like a column geometry
commutes <- data.frame(mode = c("Bicycle", "Car"), count = c(890, 1230))
ggplot(commutes, aes(mode, value = count, icon = mode, colour = mode)) +
  geom_pictogram(ncol = 5) +
  scale_icon_manual(values = c(icons::fontawesome$solid$bicycle, icons::fontawesome$solid$car)) +
  labs(value = "commuters")
#> Error in geom_pictogram(ncol = 5): Problem while converting geom to grob.
#> ℹ Error occurred in the 1st layer.
#> Caused by error in `loadNamespace()`:
#> ! there is no package called ‘grImport2’

Usage

Arguments

Value

Aesthetics

See also

Examples