hanning: Hanning Filter

In dplR: Dendrochronology Program Library in R

Description

Applies a Hanning filter of length n to x.

Usage

hanning(x, n = 7)

Arguments

x	a vector
n	length of the Hanning filter, defaults to 7

Details

This applies a low frequency Hanning (a.k.a. Hann) filter to x with weight set to n.

Value

A filtered vector.

Author(s)

Andy Bunn. Patched and improved by Mikko Korpela.

References

Oppenheim, A. V., Schafer, R. W., and Buck, J. R. (1999) Discrete-Time Signal Processing. Prentice-Hall, 2nd edition. ISBN-13: 978-0-13-754920-7.

See Also

filter

Examples

library(graphics)
library(utils)
data(ca533)
yrs <- time(ca533)
y <- ca533[, 1]
not.na <- !is.na(y)
yrs <- yrs[not.na]
y <- y[not.na]
plot(yrs, y, xlab = "Years", ylab = "Series1 (mm)",
     type = "l", col = "grey")
lines(yrs, hanning(y, n = 9), col = "red", lwd = 2)
lines(yrs, hanning(y, n = 21), col = "blue", lwd = 2)
legend("topright", c("Series", "n=9", "n=21"),
       fill=c("grey", "red", "blue"))

dplR documentation built on May 2, 2019, 6:06 p.m.