# morlet: Perform a Continuous Morlet Wavelet Transform In dplR: Dendrochronology Program Library in R

 morlet R Documentation

## Perform a Continuous Morlet Wavelet Transform

### Description

This function performs a continuous wavelet transform on a time series.

### Usage

``````morlet(y1, x1 = seq_along(y1), p2 = NULL, dj = 0.25, siglvl = 0.95)
``````

### Arguments

 `y1` `numeric` vector. Series to be transformed. `x1` `numeric`. A vector of values giving the years for the plot. Must be the same length as `length(y1)`. `p2` `numeric`. The number of power of two to be computed for the wavelet transform. Calculated from length of `y1` if `NULL`. `dj` `numeric`. Sub-octaves per octave calculated. `siglvl` `numeric`. Level for the significance test.

### Details

This performs a continuous wavelet transform of a time series. This function is typically invoked with `wavelet.plot`.

### Value

A `list` containing:

 `y` `numeric`. The original time series. `x` `numeric`. The time values. `wave` `complex`. The wavelet transform. `coi` `numeric`. The cone of influence. `period` `numeric`. The period. `Scale` `numeric`. The scale. `Signif` `numeric`. The significant values. `Power` `numeric`. The squared power.

### Note

This is a port of Torrence’s IDL code, which can be accessed through the Internet Archive Wayback Machine.

### Author(s)

Andy Bunn. Patched and improved by Mikko Korpela.

### References

Torrence, C. and Compo, G. P. (1998) A practical guide to wavelet analysis. Bulletin of the American Meteorological Society, 79(1), 61–78.

`wavelet.plot`

### Examples

``````library(utils)
data(ca533)
ca533.rwi <- detrend(rwl = ca533, method = "ModNegExp")
ca533.crn <- chron(ca533.rwi, prewhiten = FALSE)
Years <- time(ca533.crn)
CAMstd <- ca533.crn[, 1]
out.wave <- morlet(y1 = CAMstd, x1 = Years, dj = 0.1, siglvl = 0.99)
``````

dplR documentation built on June 22, 2024, 9:59 a.m.