coord_trans {ggplot2}R Documentation

coord_trans

Description

Transformed cartesian coordinate system

Usage

coord_trans(xtrans="identity", ytrans="identity", ...)

Arguments

xtrans NULL
ytrans NULL
... ignored

Details

This page describes coord_trans, see layer and qplot for how to create a complete plot from individual components.

Value

A layer

Author(s)

Hadley Wickham, http://had.co.nz/

See Also

Examples

## Not run: 
# See ?geom_boxplot for other examples

# Three ways of doing transformating in ggplot:
#  * by transforming the data
qplot(log10(carat), log10(price), data=diamonds)
#  * by transforming the scales
qplot(carat, price, data=diamonds, log="xy")
qplot(carat, price, data=diamonds) + scale_x_log10() + scale_y_log10()
#  * by transforming the coordinate system:
qplot(carat, price, data=diamonds) + coord_trans(x = "log10", y = "log10")

# The difference between transforming the scales and
# transforming the coordinate system is that scale
# transformation occurs BEFORE statistics, and coordinate
# transformation afterwards.  Coordinate transformation also 
# changes the shape of geoms:

d <- subset(diamonds, carat > 0.5)
qplot(carat, price, data = d, log="xy") + 
  geom_smooth(method="lm")
qplot(carat, price, data = d) + 
  geom_smooth(method="lm") +
  coord_trans(x = "log10", y = "log10")
  
# Here I used a subset of diamonds so that the smoothed line didn't
# drop below zero, which obviously causes problems on the log-transformed
# scale

# With a combination of scale and coordinate transformation, it's
# possible to do back-transformations:
qplot(carat, price, data=diamonds, log="xy") + 
  geom_smooth(method="lm") + 
  coord_trans(x="pow10", y="pow10")
# cf.
qplot(carat, price, data=diamonds) + geom_smooth(method = "lm")

## End(Not run)

[Package ggplot2 version 0.8.2 Index]