lines.loess: Add a Loess or a Spline Smoother

In DescTools: Tools for Descriptive Statistics

Add a Loess or a Spline Smoother

Description

Add a loess smoother to an existing plot. The function first calculates the prediction of a loess object for a reasonable amount of points, then adds the line to the plot and inserts a polygon with the confidence intervals.

Usage

## S3 method for class 'loess'
lines(x, col = Pal()[1], lwd = 2, lty = "solid",
      type = "l", n = 100, conf.level = 0.95, args.band = NULL, ...)

## S3 method for class 'smooth.spline'
lines(x, col = Pal()[1], lwd = 2, lty = "solid",
      type = "l", conf.level = 0.95, args.band = NULL, ...)

## S3 method for class 'SmoothSpline'
lines(x, col = Pal()[1], lwd = 2, lty = "solid",
      type = "l", conf.level = 0.95, args.band = NULL, ...)

Arguments

x	the loess or smooth.spline object to be plotted.
col	linecolor of the smoother. Default is DescTools's col1.
lwd	line width of the smoother.
lty	line type of the smoother.
type	type of plot, defaults to "l".
n	number of points used for plotting the fit.
conf.level	confidence level for the confidence interval. Set this to NA, if no confidence band should be plotted. Default is 0.95.
args.band	list of arguments for the confidence band, such as color or border (see DrawBand).
...	further arguments are passed to the smoother (loess() or SmoothSpline()).

Note

Loess can result in heavy computational load if there are many points!

Author(s)

Andri Signorell <[e-mail]>

See Also

loess, scatter.smooth, smooth.spline, SmoothSpline

Examples

par(mfrow=c(1,2))

x <- runif(100)
y <- rnorm(100)
plot(x, y)
lines(loess(y~x))

plot(temperature ~ delivery_min, data=d.pizza)
lines(loess(temperature ~ delivery_min, data=d.pizza))

plot(temperature ~ delivery_min, data=d.pizza)
lines(loess(temperature ~ delivery_min, data=d.pizza), conf.level = 0.99,
            args.band = list(col=SetAlpha("red", 0.4), border="black") )

# the default values from scatter.smooth
lines(loess(temperature ~ delivery_min, data=d.pizza,
            span=2/3, degree=1, family="symmetric"), col="red")

DescTools documentation built on Sept. 26, 2024, 1:07 a.m.