R: Scatter Plot with Smooth Curve Fitted by 'loess'

scatter.smooth {stats}

R Documentation

Scatter Plot with Smooth Curve Fitted by `loess`

Description

Plot and add a smooth curve computed by loess to a scatter plot.

Usage

scatter.smooth(x, y = NULL, span = 2/3, degree = 1,
    family = c("symmetric", "gaussian"),
    xlab = NULL, ylab = NULL,
    ylim = range(y, pred$y, na.rm = TRUE),
    evaluation = 50, ..., lpars = list())

loess.smooth(x, y, span = 2/3, degree = 1,
    family = c("symmetric", "gaussian"), evaluation = 50, ...)

Arguments

`x`, `y`	the `x` and `y` arguments provide the x and y coordinates for the plot. Any reasonable way of defining the coordinates is acceptable. See the function `xy.coords` for details.
`span`	smoothness parameter for `loess`.
`degree`	degree of local polynomial used.
`family`	if `"gaussian"` fitting is by least-squares, and if `family = "symmetric"` a re-descending M estimator is used. Can be abbreviated.
`xlab`	label for x axis.
`ylab`	label for y axis.
`ylim`	the y limits of the plot.
`evaluation`	number of points at which to evaluate the smooth curve.
`...`	For `scatter.smooth()`, graphical parameters, passed to `plot()` only. For `loess.smooth`, control parameters passed to `loess.control`.
`lpars`	a `list` of arguments to be passed to `lines()`.

Details

loess.smooth is an auxiliary function which evaluates the loess smooth at evaluation equally spaced points covering the range of x.

Value

For scatter.smooth, none.

For loess.smooth, a list with two components, x (the grid of evaluation points) and y (the smoothed values at the grid points).

Examples

require(graphics)

with(cars, scatter.smooth(speed, dist))
## or with dotted thick smoothed line results :
with(cars, scatter.smooth(speed, dist, lpars =
                    list(col = "red", lwd = 3, lty = 3)))

[Package stats version 4.4.1 Index]

Scatter Plot with Smooth Curve Fitted by loess