ggpmisc (version 0.3.9)

geom_plot: Inset plots

Description

geom_plot and geom_plot_npc add ggplot objects as insets to the base ggplot, using syntax similar to that of geom_label. In most respects they behave as any other ggplot geometry: a layer con contain multiple tables and faceting works as usual.

Usage

geom_plot(
  mapping = NULL,
  data = NULL,
  stat = "identity",
  position = "identity",
  ...,
  na.rm = FALSE,
  show.legend = FALSE,
  inherit.aes = FALSE
)
geom_plot_npc(
  mapping = NULL,
  data = NULL,
  stat = "identity",
  position = "identity",
  ...,
  na.rm = FALSE,
  show.legend = FALSE,
  inherit.aes = FALSE
)

Arguments

mapping

The aesthetic mapping, usually constructed with aes or aes_. Only needs to be set at the layer level if you are overriding the plot defaults.

data

A layer specific data set - only needed if you want to override the plot defaults.

stat

The statistical transformation to use on the data for this layer, as a string.

position

Position adjustment, either as a string, or the result of a call to a position adjustment function.

...

other arguments passed on to layer. This can include aesthetics whose values you want to set, not map. See layer for more details.

na.rm

If FALSE (the default), removes missing values with a warning. If TRUE silently removes missing values.

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.

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. borders.

Inset alignment

You can modify inset plot alignment with the vjust and hjust aesthetics. These can either be a number between 0 (right/bottom) and 1 (top/left) or a character ("left", "middle", "right", "bottom", "center", "top"). The angle aesthetics can be used to rotate the inset plots.

Inset size and aspect

You can modify the size of the inset plot with the vp.width and vp.height aesthetics. Arguments can be a number between 0 (smallest possible inset) and 1 (whole plotting area width or height). The default value for for both of these aesthetics is 1/3. If the coordinates are "free" the plot stretches to fill the viewport. However, if the coordinates of the inset are "fixed" and the aspect ratio of the viewport is different to that of the inset, the viewport will be surrounded on either $x$ or $y$ margins by invisible space, which may look as if the position of the inset is wrong.

Known problem!

In some cases when explicit coordinates are added to the inner plot, it may be also necessary to add explicitly coordinates to the outer plots.

Details

The "width" and "height" of an inset as for a text element are 0, so stacking and dodging inset plots will not work by default, and axis limits are not automatically expanded to include all inset plots. Obviously, insets do have height and width, but they are physical units, not data units. The amount of space they occupy on the main plot is not constant in data units of the base plot: when you modify scale limits, inset plots stay the same size relative to the physical size of the base plot.

References

The idea of implementing a geom_custom() for grobs has been discussed as an issue at https://github.com/tidyverse/ggplot2/issues/1399.

See Also

Other geometries adding layers with insets: geom_grob(), geom_table()

Examples

# NOT RUN {
# inset plot with enlarged detail from a region of the main plot
library(tibble)
p <-
  ggplot(data = mtcars, mapping = aes(wt, mpg)) +
  geom_point()

df <- tibble(x = 0.01, y = 0.01,
             plot = list(p +
                         coord_cartesian(xlim = c(3, 4),
                                         ylim = c(13, 16)) +
                         labs(x = NULL, y = NULL) +
                         theme_bw(10)))
p +
  expand_limits(x = 0, y = 0) +
  geom_plot_npc(data = df, aes(npcx = x, npcy = y, label = plot))

p +
  expand_limits(x = 0, y = 0) +
  geom_plot_npc(data = df,
                vp.width = 1/2, vp.height = 1/4,
                aes(npcx = x, npcy = y, label = plot))

# }