geom_table: Inset tables

In ggpp: Grammar Extensions to 'ggplot2'

Inset tables

Description

geom_table and geom_table_npc add data frames as table insets to the base ggplot, using syntax similar to that of geom_text and geom_text_s. In most respects they behave as any other ggplot geometry: they add a layer containing one or more grobs and grouping and faceting works as usual. The most common use of geom_table is to add data labels that are whole tables rather than text. geom_table_npc is used to add tables as annotations to plots, but contrary to layer function annotate, geom_table_npc is data driven and respects grouping and facets, thus plot insets can differ among panels.

Usage

geom_table(
  mapping = NULL,
  data = NULL,
  stat = "identity",
  position = "identity",
  ...,
  nudge_x = 0,
  nudge_y = 0,
  default.colour = "black",
  default.color = default.colour,
  colour.target = "box",
  color.target = colour.target,
  default.alpha = 1,
  alpha.target = "all",
  add.segments = TRUE,
  box.padding = 0.25,
  point.padding = 1e-06,
  segment.linewidth = 0.5,
  min.segment.length = 0,
  arrow = NULL,
  table.theme = NULL,
  table.rownames = FALSE,
  table.colnames = TRUE,
  table.hjust = 0.5,
  parse = FALSE,
  na.rm = FALSE,
  show.legend = FALSE,
  inherit.aes = FALSE
)

geom_table_npc(
  mapping = NULL,
  data = NULL,
  stat = "identity",
  position = "identity",
  ...,
  table.theme = NULL,
  table.rownames = FALSE,
  table.colnames = TRUE,
  table.hjust = 0.5,
  parse = FALSE,
  na.rm = FALSE,
  show.legend = FALSE,
  inherit.aes = FALSE
)

Arguments

mapping	The aesthetic mapping, usually constructed with 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
...	other arguments passed on to layer. This can include aesthetics whose values you want to set, not map. See layer for more details.
nudge_x, nudge_y	Horizontal and vertical adjustments to nudge the starting position of each text label. The units for nudge_x and nudge_y are the same as for the data units on the x-axis and y-axis.
default.colour, default.color	A colour definition to use for elements not targeted by the colour aesthetic.
colour.target, color.target	A vector of character strings; "all", "box" and "segment" or "none".
default.alpha	numeric in [0..1] A transparency value to use for elements not targeted by the alpha aesthetic.
alpha.target	A vector of character strings; "all", "segment", "box", "box.line", and "box.fill" or "none".
add.segments	logical Display connecting segments or arrows between original positions and displaced ones if both are available.
box.padding, point.padding	numeric By how much each end of the segments should shortened in mm.
segment.linewidth	numeric Width of the segments or arrows in mm.
min.segment.length	numeric Segments shorter that the minimum length are not rendered, in mm.
arrow	specification for arrow heads, as created by arrow
table.theme	NULL, list or function A gridExtra ttheme defintion, or a constructor for a ttheme or NULL for default.
table.rownames, table.colnames	logical flag to enable or disable printing of row names and column names.
table.hjust	numeric Horizontal justification for the core and column headings of the table.
parse	If TRUE, the labels will be parsed into expressions and displayed as described in ?plotmath.
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.

Details

By default geom_table() uses position_nudge_center which is backwards compatible with position_nudge but provides additional control on the direction of the nudging. In contrast to position_nudge, position_nudge_center and all other position functions defined in packages 'ggpp' and 'ggrepel' keep the original coordinates thus allowing the plotting of connecting segments and arrows.

This geom works only with tibbles as data, as its expects a list of data frames (or tibbles) to be mapped to the label aesthetic. A table is built with function gridExtra::gtable for each data frame in the list, and formatted according to a table theme or ttheme. The character strings in the data frame can be parsed into R expressions so the inset tables can include maths.

If the argument passed to table.theme is a constructor function (passing its name without parenthesis), the values mapped to size, colour, fill, alpha, and family aesthetics will the passed to this theme constructor for each individual table. In contrast, if a ready constructed ttheme stored as a list object is passed as argument (e.g., by calling the constructor, using constructor name followed by parenthesis), it will be used as is, i.e., mappings to aesthetics such as colour are ignored if present. By default the constructor ttheme_gtdefault is used and colour and fill, are mapped to NA. Mapping these aesthetics to NA triggers the use of the default base_colour of the ttheme. As the table is built with function gridExtra::gtable(), for formatting details, please, consult tableGrob.

The x and y aesthetics determine the position of the whole inset table, similarly to that of a text label, justification is interpreted as indicating the position of the inset table with respect to its horizontal and vertical axes (rows and columns in the data frame), and angle is used to rotate the inset table as a whole.

Of these two geoms only geom_grob supports the plotting of segments, as geom_grob_npc uses a coordinate system that is unrelated to data units and data.In the case of geom_table_npc, npcx and npcy aesthetics determine the position of the inset table. Justification as described above for .

Value

A plot layer instance.

Alignment

You can modify text 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"). In addition, you can use special alignments for justification including "position", "inward" and "outward". Inward always aligns text towards the center of the plotting area, and outward aligns it away from the center of the plotting area. If tagged with _mean or _median (e.g., "outward_mean") the mean or median of the data in the panel along the corresponding axis is used as center. If the characters following the underscore represent a number (e.g., "outward_10.5") the reference point will be this value in data units. Position justification is computed based on the direction of the displacement of the position of the label so that each individual text or label is justified outwards from its original position. The default justification is "position".

If no position displacement is applied, or a position function defined in 'ggplot2' is used, these geometries behave similarly to the corresponding ones from package 'ggplot2' with a default justification of 0.5 and no segment drawn.

Position functions

Many layer functions from package 'ggpp' are designed to work seamlessly with position functions that keep, rather than discard, the original x and y positions in data when computing a new displaced position. See position_nudge_keep, position_dodge_keep, position_jitter_keep, position_nudge_center, position_nudge_line, position_nudge_to, position_dodgenudge, position_jitternudge, and position_stacknudge for examples and details of their use.

Plot boundaries and clipping

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.

Note

Complex tables with annotations or different colouring of rows or cells can be constructed with functions in package 'gridExtra' or in any other way as long as they can be saved as grid graphical objects and then added to a ggplot as a new layer with geom_grob.

References

This geometry is inspired on answers to two questions in Stackoverflow. In contrast to these earlier examples, the current geom obeys the grammar of graphics, and attempts to be consistent with the behaviour of 'ggplot2' geometries. https://stackoverflow.com/questions/12318120/adding-table-within-the-plotting-region-of-a-ggplot-in-r https://stackoverflow.com/questions/25554548/adding-sub-tables-on-each-panel-of-a-facet-ggplot-in-r?

See Also

Formatting of tables stat_fmt_table, ttheme_gtdefault, ttheme_set, tableGrob.

Other geometries adding layers with insets: geom_plot()

Examples

library(dplyr)
library(tibble)

mtcars %>%
  group_by(cyl) %>%
  summarize(wt = mean(wt), mpg = mean(mpg)) %>%
  ungroup() %>%
  mutate(wt = sprintf("%.2f", wt),
         mpg = sprintf("%.1f", mpg)) -> tb

df <- tibble(x = 5.45, y = 34, tb = list(tb))

# using defaults
ggplot(mtcars, aes(wt, mpg, colour = factor(cyl))) +
  geom_point() +
  geom_table(data = df,
             aes(x = x, y = y, label = tb))

ggplot(mtcars,
       aes(wt, mpg, colour = factor(cyl))) +
  geom_point() +
  geom_table(data = df,
             aes(x = x, y = y, label = tb),
             table.rownames = TRUE,
             table.theme = ttheme_gtstripes)

# settings aesthetics to constants
ggplot(mtcars,
       aes(wt, mpg, colour = factor(cyl))) +
  geom_point() +
  geom_table(data = df,
             aes(x = x, y = y, label = tb),
             color = "red", fill = "#FFCCCC",
             family = "serif", size = 5,
             angle = 90, vjust = 0)

# passing a theme constructor as argument
ggplot(mtcars,
       aes(wt, mpg, colour = factor(cyl))) +
  geom_point() +
  geom_table(data = df,
             aes(x = x, y = y, label = tb),
             table.theme = ttheme_gtminimal) +
  theme_classic()

df2 <- tibble(x = 5.45,
              y = c(34, 29, 24),
              x1 = c(2.29, 3.12, 4.00),
              y1 = c(26.6, 19.7, 15.1),
              cyl = c(4, 6, 8),
              tb = list(tb[1, 1:3], tb[2, 1:3], tb[3, 1:3]))

# mapped aesthetics
ggplot(mtcars,
       aes(wt, mpg, color = factor(cyl))) +
  geom_point() +
  geom_table(data = df2,
             inherit.aes = TRUE,
             mapping = aes(x = x, y = y, label = tb))

# nudging and segments
ggplot(mtcars,
       aes(wt, mpg, color = factor(cyl))) +
  geom_point(show.legend = FALSE) +
  geom_table(data = df2,
             inherit.aes = TRUE,
             mapping = aes(x = x1, y = y1, label = tb),
             nudge_x = 0.7, nudge_y = 3,
             vjust = 0.5, hjust = 0.5,
             arrow = arrow(length = unit(0.5, "lines"))) +
  theme_classic()

# Using native plot coordinates instead of data coordinates
dfnpc <- tibble(x = 0.95, y = 0.95, tb = list(tb))

ggplot(mtcars,
       aes(wt, mpg, colour = factor(cyl))) +
  geom_point() +
  geom_table_npc(data = dfnpc,
                 aes(npcx = x, npcy = y, label = tb))

ggpp documentation built on Nov. 8, 2023, 1:10 a.m.