ggplot2 (version 0.9.0)

geom_path: Connect observations in original order

Description

Connect observations in original order

Usage

geom_path(mapping = NULL, data = NULL, stat = "identity",
    position = "identity", lineend = "butt",
    linejoin = "round", linemitre = 1, na.rm = FALSE,
    arrow = NULL, ...)

Arguments

lineend

Line end style (round, butt, square)

linejoin

Line join style (round, mitre, bevel)

linemitre

Line mitre limit (number greater than 1)

arrow

Arrow specification, as created by ?grid::arrow

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.

See Also

geom_line: Functional (ordered) lines; geom_polygon: Filled paths (polygons); geom_segment: Line segments

Examples

# Generate data
library(plyr)
myear <- ddply(movies, .(year), colwise(mean, .(length, rating)))
p <- ggplot(myear, aes(length, rating))
p + geom_path()

# Add aesthetic mappings
p + geom_path(aes(size = year))
p + geom_path(aes(colour = year))

# Change scale
p + geom_path(aes(size = year)) + scale_size(range = c(1, 3))

# Set aesthetics to fixed value
p + geom_path(colour = "green")

# Control line join parameters
df <- data.frame(x = 1:3, y = c(4, 1, 9))
base <- ggplot(df, aes(x, y))
base + geom_path(size = 10)
base + geom_path(size = 10, lineend = "round")
base + geom_path(size = 10, linejoin = "mitre", lineend = "butt")

# Use qplot instead
qplot(length, rating, data=myear, geom="path")

# Using economic data:
# How is unemployment and personal savings rate related?
qplot(unemploy/pop, psavert, data=economics)
qplot(unemploy/pop, psavert, data=economics, geom="path")
qplot(unemploy/pop, psavert, data=economics, geom="path", size=as.numeric(date))

# How is rate of unemployment and length of unemployment?
qplot(unemploy/pop, uempmed, data=economics)
qplot(unemploy/pop, uempmed, data=economics, geom="path")
qplot(unemploy/pop, uempmed, data=economics, geom="path") +
  geom_point(data=head(economics, 1), colour="red") +
  geom_point(data=tail(economics, 1), colour="blue")
qplot(unemploy/pop, uempmed, data=economics, geom="path") +
  geom_text(data=head(economics, 1), label="1967", colour="blue") +
  geom_text(data=tail(economics, 1), label="2007", colour="blue")

# geom_path removes missing values on the ends of a line.
# use na.rm = T to suppress the warning message
df <- data.frame(
  x = 1:5,
  y1 = c(1, 2, 3, 4, NA),
  y2 = c(NA, 2, 3, 4, 5),
  y3 = c(1, 2, NA, 4, 5),
  y4 = c(1, 2, 3, 4, 5))
qplot(x, y1, data = df, geom = c("point","line"))
qplot(x, y2, data = df, geom = c("point","line"))
qplot(x, y3, data = df, geom = c("point","line"))
qplot(x, y4, data = df, geom = c("point","line"))

# Setting line type vs colour/size
# Line type needs to be applied to a line as a whole, so it can
# not be used with colour or size that vary across a line

x <- seq(0.01, .99, length=100)
df <- data.frame(x = rep(x, 2), y = c(qlogis(x), 2 * qlogis(x)), group = rep(c("a","b"), each=100))
p <- ggplot(df, aes(x=x, y=y, group=group))

# Should work
p + geom_line(linetype = 2)
p + geom_line(aes(colour = group), linetype = 2)
p + geom_line(aes(colour = x))

# Should fail
should_stop(p + geom_line(aes(colour = x), linetype=2))

# Use the arrow parameter to add an arrow to the line
# See ?grid::arrow for more details
library(grid)
c <- ggplot(economics, aes(x = date, y = pop))
# Arrow defaults to "last"
c + geom_path(arrow = arrow())
c + geom_path(arrow = arrow(angle = 15, ends = "both", length = unit(0.6, "inches")))