geom_segment {ggplot2}R Documentation

Single line segments.

Description

Single line segments.

Usage

geom_segment(mapping = NULL, data = NULL, stat = "identity",
  position = "identity", arrow = NULL, lineend = "butt", na.rm = FALSE,
  ...)

Arguments

mapping

The aesthetic mapping, usually constructed with aes or aes_string. 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.

stat

The statistical transformation to use on the data for this layer.

position

The position adjustment to use for overlapping points on this layer

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.

...

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

Aesthetics

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

See Also

geom_path and geom_line for multi- segment lines and paths.

Examples

library(grid) # needed for arrow function
p <- ggplot(seals, aes(x = long, y = lat))
(p <- p + geom_segment(aes(xend = long + delta_long, yend = lat + delta_lat),
  arrow = arrow(length = unit(0.1,"cm"))))

if (require("maps")) {

xlim <- range(seals$long)
ylim <- range(seals$lat)
usamap <- data.frame(map("world", xlim = xlim, ylim = ylim, plot =
FALSE)[c("x","y")])
usamap <- rbind(usamap, NA, data.frame(map('state', xlim = xlim, ylim
= ylim, plot = FALSE)[c("x","y")]))
names(usamap) <- c("long", "lat")

p + geom_path(data = usamap) + scale_x_continuous(limits = xlim)
}

# 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))

qplot(x, Freq, data = counts, geom = "segment",
  yend = 0, xend = x, size = I(10))

# Adding line segments
library(grid) # needed for arrow function
b <- ggplot(mtcars, aes(wt, mpg)) + geom_point()
b + geom_segment(aes(x = 2, y = 15, xend = 2, yend = 25))
b + geom_segment(aes(x = 2, y = 15, xend = 3, yend = 15))
b + geom_segment(aes(x = 5, y = 30, xend = 3.5, yend = 25),
   arrow = arrow(length = unit(0.5, "cm")))
[Package ggplot2 version 1.0.1 Index]