Question

I’m drawing a ROC curve and R is putting to much space between the curve and the plot border. I want values at x = 0 to touch the y-axis and points at y = 1 to touch the upper border of the plot.

This image shows exactly how I want it:

http://en.wikipedia.org/wiki/File:Roccurves.png

Anyone got any idea?

Answer 1

For base graphics, use the axis style parameters, xaxs and yaxs, to constrain the plotting limits to the of the data.

dfr <- data.frame(x = 0:1, y = 0:1)
par(xaxs = "i", yaxs = "i")
with(dfr, plot(x, y))

For lattice, you use the xlim and ylim parameters.

xyplot(y ~ x, dfr, xlim = range(dfr$x), ylim = range(dfr$y))

For ggplot2, use coord_cartesian.

ggplot(dfr, aes(x, y)) + 
  geom_point() + 
  coord_cartesian(xlim = range(dfr$x), ylim = range(dfr$y))