Transformed cartesian coordinate system.
Usage
coord_trans(xtrans = "identity", ytrans = "identity", limx = NULL, limy = NULL)
Arguments
- xtrans,ytrans
- transformers for x and y axes
- limx,limy
- limits for x and y axes. (Named so for backward compatability)
Description
coord_trans is different to scale transformations
in that it occurs after statistical transformation and
will affect the visual appearance of geoms - there is no
guarantee that straight lines will continue to be
straight.
Details
All current transformations only work with continuous
values - see trans_new for list of
transformations, and instructions on how to create your
own.
Examples
# 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: library(scales) qplot(carat, price, data=diamonds, log="xy") + geom_smooth(method="lm") + coord_trans(x = exp_trans(10), y = exp_trans(10))
# cf. qplot(carat, price, data=diamonds) + geom_smooth(method = "lm")
# Also works with discrete scales df <- data.frame(a = abs(rnorm(26)),letters) plot <- ggplot(df,aes(a,letters)) + geom_point() plot + coord_trans(x = "log10")
plot + coord_trans(x = "sqrt")
