stat_quadrant_counts: Number of observations in quadrants

In ggpp: Grammar Extensions to 'ggplot2'

Number of observations in quadrants

Description

stat_quadrant_counts() counts the number of observations in each quadrant of a plot panel. By default it adds a text label to the far corner of each quadrant. It can also be used to obtain the total number of observations in each of two pairs of quadrants or in the whole panel. Grouping is ignored, so en every case a single count is computed for each quadrant in a plot panel.

Usage

stat_quadrant_counts(
  mapping = NULL,
  data = NULL,
  geom = "text_npc",
  position = "identity",
  quadrants = NULL,
  pool.along = c("none", "x", "y", "xy"),
  xintercept = 0,
  yintercept = 0,
  label.x = NULL,
  label.y = NULL,
  digits = 2,
  na.rm = FALSE,
  show.legend = FALSE,
  inherit.aes = TRUE,
  ...
)

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 dataset - only needed if you want to override the plot defaults.
geom	The geometric object to use display the data
position	The position adjustment to use on this layer
quadrants	integer vector indicating which quadrants are of interest, with a OL indicating the whole plot.
pool.along	character, one of "none", "x" or "y", indicating which quadrants to pool to calculate counts by pair of quadrants.
xintercept, yintercept	numeric the coordinates of the origin of the quadrants.
label.x, label.y	numeric Coordinates (in npc units) to be used for absolute positioning of the labels.
digits	integer Number of digits for fraction and percent labels.
na.rm	a logical indicating whether NA values should be stripped before the computation proceeds.
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 should not inherit behaviour from the default plot specification, e.g., borders.
...	other arguments passed on to layer. This can include aesthetics whose values you want to set, not map. See layer for more details.

Details

This statistic can be used to automatically count observations in each of the four quadrants of a plot, and by default add these counts as text labels. Values exactly equal to xintercept or yintercept are counted together with those larger than the intercepts. An argument value of zero, passed to formal parameter quadrants is interpreted as a request for the count of all observations in each plot panel.

The default origin of quadrants is at xintercept = 0, yintercept = 0. Also by default, counts are computed for all quadrants within the x and y scale limits, but ignoring any marginal scale expansion. The default positions of the labels is in the farthest corner or edge of each quadrant using npc coordinates. Consequently, when using facets even with free limits for x and y axes, the location of the labels is consistent across panels. This is achieved by use of geom = "text_npc" or geom = "label_npc". To pass the positions in native data units, pass geom = "text" explicitly as argument.

Value

A plot layer instance. Using as output data the counts of observations per plot quadrant.

Computed variables

Data frame with one to four rows, one for each quadrant for which counts are counted in data.

quadrant

integer, one of 0:4

x

x value of label position in data units

y

y value of label position in data units

npcx

x value of label position in npc units

npcy

y value of label position in npc units

count

number of observations in the quadrant(s)

total

number of onservations in data

count.label

number of observations as character

pc.label

percent of observations as character

fr.label

fraction of observations as character

.

As shown in one example below geom_debug can be used to print the computed values returned by any statistic. The output shown includes also values mapped to aesthetics, like label in the example.

See Also

Other Functions for quadrant and volcano plots: geom_quadrant_lines(), stat_panel_counts()

Examples

# generate artificial data
set.seed(4321)
x <- -50:50
y <- rnorm(length(x), mean = 0)
my.data <- data.frame(x, y)

# using automatically generated text labels, default origin at (0, 0)

ggplot(my.data, aes(x, y)) +
  geom_point() +
  geom_quadrant_lines() +
  stat_quadrant_counts()

ggplot(my.data, aes(x, y)) +
  geom_point() +
  geom_quadrant_lines() +
  stat_quadrant_counts(aes(label = after_stat(pc.label)))

ggplot(my.data, aes(x, y)) +
  geom_point() +
  geom_quadrant_lines() +
  stat_quadrant_counts(aes(label = after_stat(fr.label)))

ggplot(my.data, aes(x, y)) +
  geom_point() +
  geom_quadrant_lines() +
  stat_quadrant_counts(aes(label = after_stat(dec.label)))

ggplot(my.data, aes(x, y)) +
 geom_point() +
  geom_quadrant_lines() +
  stat_quadrant_counts(aes(label = sprintf("%i observations", after_stat(count)))) +
  scale_y_continuous(expand = expansion(c(0.05, 0.15))) # reserve space

# user specified origin

ggplot(my.data, aes(x, y)) +
  geom_quadrant_lines(colour = "blue", xintercept = 10, yintercept = -1) +
  stat_quadrant_counts(colour = "blue", xintercept = 10, yintercept = -1) +
  geom_point() +
  scale_y_continuous(expand = expansion(mult = 0.15))

ggplot(my.data, aes(x, y)) +
  geom_quadrant_lines(colour = "blue", xintercept = 10, yintercept = -1) +
  stat_quadrant_counts(aes(label = after_stat(pc.label)),
                       colour = "blue", xintercept = 10, yintercept = -1) +
  geom_point() +
  scale_y_continuous(expand = expansion(mult = 0.15))

# more digits in labels

ggplot(my.data, aes(x, y)) +
  geom_quadrant_lines(colour = "blue", xintercept = 10, yintercept = -1) +
  stat_quadrant_counts(aes(label = after_stat(pc.label)), digits = 3,
                       colour = "blue", xintercept = 10, yintercept = -1) +
  geom_point() +
  scale_y_continuous(expand = expansion(mult = 0.15))

ggplot(my.data, aes(x, y)) +
  geom_quadrant_lines(colour = "blue", xintercept = 10, yintercept = -1) +
  stat_quadrant_counts(aes(label = after_stat(fr.label)),
                       colour = "blue", xintercept = 10, yintercept = -1) +
  geom_point() +
  scale_y_continuous(expand = expansion(mult = 0.15))

# grouped quadrants

ggplot(my.data, aes(x, y)) +
  geom_quadrant_lines(colour = "blue",
                      pool.along = "x") +
  stat_quadrant_counts(colour = "blue", label.x = "right",
                       pool.along = "x") +
  geom_point() +
  scale_y_continuous(expand = expansion(mult = 0.15))

# whole panel

ggplot(my.data, aes(x, y)) +
  geom_point() +
  stat_quadrant_counts(quadrants = 0, label.x = "left", label.y = "bottom") +
  scale_y_continuous(expand = expansion(mult = c(0.15, 0.05)))

# use a different geometry

ggplot(my.data, aes(x, y)) +
  geom_point() +
  stat_quadrant_counts(geom = "text") # use geom_text()

# Numeric values can be used to build labels with alternative formats
# Here with sprintf(), but paste() and format() also work.

ggplot(my.data, aes(x, y)) +
  geom_quadrant_lines(colour = "blue") +
  stat_quadrant_counts(aes(label = sprintf("%i of %i genes",
                       after_stat(count), after_stat(total))),
                       colour = "blue") +
  geom_point() +
  scale_y_continuous(expand = expansion(mult = 0.15))

# We use geom_debug() to see the computed values

gginnards.installed <- requireNamespace("gginnards", quietly = TRUE)
if (gginnards.installed) {
  library(gginnards)

  ggplot(my.data, aes(x, y)) +
    geom_point() +
    stat_quadrant_counts(geom = "debug")

  ggplot(my.data, aes(x, y)) +
    geom_point() +
    stat_quadrant_counts(geom = "debug", xintercept = 50)
}

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