Dodge overlapping objects side-to-side

Dodging preserves the vertical position of an geom while adjusting the horizontal position. position_dodge() requires the grouping variable to be be specified in the global or geom_* layer. Unlike position_dodge(), position_dodge2() works without a grouping variable in a layer. position_dodge2() works with bars and rectangles, but is particulary useful for arranging box plots, which can have variable widths.

position_dodge(width = NULL, preserve = c("total", "single"))

position_dodge2(
  width = NULL,
  preserve = c("total", "single"),
  padding = 0.1,
  reverse = FALSE
)

Arguments

width: Dodging width, when different to the width of the individual elements. This is useful when you want to align narrow geoms with wider geoms. See the examples.
preserve: Should dodging preserve the total width of all elements at a position, or the width of a single element?
padding: Padding between elements at the same position. Elements are shrunk by this proportion to allow space between them. Defaults to 0.1.
reverse: If TRUE, will reverse the default stacking order. This is useful if you're rotating both the plot and legend.

Examples

ggplot(mtcars, aes(factor(cyl), fill = factor(vs))) +
  geom_bar(position = "dodge2")


# By default, dodging with `position_dodge2()` preserves the total width of
# the elements. You can choose to preserve the width of each element with:
ggplot(mtcars, aes(factor(cyl), fill = factor(vs))) +
  geom_bar(position = position_dodge2(preserve = "single"))


# \donttest{
ggplot(diamonds, aes(price, fill = cut)) +
  geom_histogram(position="dodge2")
#> `stat_bin()` using `bins = 30`. Pick better value with `binwidth`.

# see ?geom_bar for more examples

# In this case a frequency polygon is probably a better choice
ggplot(diamonds, aes(price, colour = cut)) +
  geom_freqpoly()
#> `stat_bin()` using `bins = 30`. Pick better value with `binwidth`.

# }

# Dodging with various widths -------------------------------------
# To dodge items with different widths, you need to be explicit
df <- data.frame(
  x = c("a","a","b","b"),
  y = 2:5,
  g = rep(1:2, 2)
)
p <- ggplot(df, aes(x, y, group = g)) +
  geom_col(position = "dodge", fill = "grey50", colour = "black")
p


# A line range has no width:
p + geom_linerange(aes(ymin = y - 1, ymax = y + 1), position = "dodge")
#> Warning: Width not defined. Set with `position_dodge(width = ?)`


# So you must explicitly specify the width
p + geom_linerange(
  aes(ymin = y - 1, ymax = y + 1),
  position = position_dodge(width = 0.9)
)


# The same principle applies to error bars, which are usually
# narrower than the bars
p + geom_errorbar(
  aes(ymin = y - 1, ymax = y + 1),
  width = 0.2,
  position = "dodge"
)

p + geom_errorbar(
  aes(ymin = y - 1, ymax = y + 1),
  width = 0.2,
  position = position_dodge(width = 0.9)
)


# Box plots use position_dodge2 by default, and bars can use it too
ggplot(mpg, aes(factor(year), displ)) +
  geom_boxplot(aes(colour = hwy < 30))


ggplot(mpg, aes(factor(year), displ)) +
  geom_boxplot(aes(colour = hwy < 30), varwidth = TRUE)


ggplot(mtcars, aes(factor(cyl), fill = factor(vs))) +
  geom_bar(position = position_dodge2(preserve = "single"))


ggplot(mtcars, aes(factor(cyl), fill = factor(vs))) +
  geom_bar(position = position_dodge2(preserve = "total"))

Arguments

See also

Examples