Single line segments.

Usage

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

Arguments

arrow

specification for arrow heads, as created by arrow()

lineend

Line end style (round, butt, square)

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 overlappling points on this layer

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.

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)
}

Warning message:
Removed 21 rows containing missing values (geom_segment).


# 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")))

See also