Line segments and curves.

Usage

geom_segment(mapping = NULL, data = NULL, stat = "identity", position = "identity", ..., arrow = NULL, lineend = "butt", na.rm = FALSE, show.legend = NA, inherit.aes = TRUE)
geom_curve(mapping = NULL, data = NULL, stat = "identity", position = "identity", ..., curvature = 0.5, angle = 90, ncp = 5, arrow = NULL, lineend = "butt", na.rm = FALSE, show.legend = NA, inherit.aes = TRUE)

Arguments

mapping
Set of aesthetic mappings created by aes or 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.
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. These are often aesthetics, used to set an aesthetic to a fixed value, like color = "red" or size = 3. They may also be parameters to the paired geom/stat.
arrow
specification for arrow heads, as created by arrow()
lineend
Line end style (round, butt, square)
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.
curvature
A numeric value giving the amount of curvature. Negative values produce left-hand curves, positive values produce right-hand curves, and zero produces a straight line.
angle
A numeric value between 0 and 180, giving an amount to skew the control points of the curve. Values less than 90 skew the curve towards the start point and values greater than 90 skew the curve towards the end point.
ncp
The number of control points used to draw the curve. More control points creates a smoother curve.

Description

geom_segment draws a straight line between points (x1, y1) and (x2, y2). geom_curve draws a curved line.

Aesthetics

geom_segment understands the following aesthetics (required aesthetics are in bold):

  • x
  • xend
  • y
  • yend
  • alpha
  • colour
  • linetype
  • size

Examples

b <- ggplot(mtcars, aes(wt, mpg)) + geom_point() df <- data.frame(x1 = 2.62, x2 = 3.57, y1 = 21.0, y2 = 15.0) b + geom_curve(aes(x = x1, y = y1, xend = x2, yend = y2, colour = "curve"), data = df) + geom_segment(aes(x = x1, y = y1, xend = x2, yend = y2, colour = "segment"), data = df)

b + geom_curve(aes(x = x1, y = y1, xend = x2, yend = y2), data = df, curvature = -0.2)

b + geom_curve(aes(x = x1, y = y1, xend = x2, yend = y2), data = df, curvature = 1)

b + geom_curve( aes(x = x1, y = y1, xend = x2, yend = y2), data = df, arrow = arrow(length = unit(0.03, "npc")) )

ggplot(seals, aes(long, lat)) + geom_segment(aes(xend = long + delta_long, yend = lat + delta_lat), arrow = arrow(length = unit(0.1,"cm"))) + borders("state")

# You can also use geom_segment to recreate plot(type = "h") : counts <- as.data.frame(table(x = rpois(100,5))) counts$x <- as.numeric(as.character(counts$x)) with(counts, plot(x, Freq, type = "h", lwd = 10))

ggplot(counts, aes(x, Freq)) + geom_segment(aes(xend = x, yend = 0), size = 10, lineend = "butt")

See also

geom_path and geom_line for multi- segment lines and paths. geom_spoke for a segment parameterised by a location (x, y), and an angle and radius.