How can I use spline() with ggplot?

r ggplot2 spline
David LeBauer picture David LeBauer · Dec 21, 2010 · Viewed 18.4k times · Source

I would like to fit my data using spline(y~x) but all of the examples that I can find use a spline with smoothing, e.g. lm(y~ns(x), df=_).

I want to use spline() specifically because I am using this to do the analysis represented by the plot that I am making.

Is there a simple way to use spline() in ggplot?

I have considered the hackish approach of fitting a line using 

geom_smooth(aes(x=(spline(y~x)$x, y=spline(y~x)$y))

but I would prefer not to have to resort to this.

Thanks!

Answer

kohske picture kohske · Dec 22, 2010

is this what you want?

n <- 10
d <- data.frame(x = 1:n, y = rnorm(n))
ggplot(d,aes(x,y)) + geom_point() + 
  geom_line(data=data.frame(spline(d, n=n*10)))

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