plot.dwt: Plot DWT Coefficients

In wavelets: Functions for Computing Wavelet Filters, Wavelet Transforms and Multiresolution Analyses

Description

Plot DWT wavelet and scaling coefficients.

Usage

## S3 method for class 'dwt'
plot(x, levels = NULL, draw.boundary = FALSE, type = "stack",
col.plot = "black", col.boundary = "red", X.xtick.at = NULL, X.ytick.at
= NULL, Stack.xtick.at = NULL, Stack.ytick.at = NULL, X.xlab = "t",
y.rlabs = TRUE, plot.X = TRUE, plot.W = TRUE, plot.V = TRUE, ...)

Arguments

x	An object of class dwt.
levels	Number, vector, or list of two vectors indicating range of levels to plot. See details.
draw.boundary	Logical value indicating whether to draw boundary coefficients.
type	Type of plot to draw. Currently only "stack" is implemented.
col.plot	Color of wavelet and scaling coefficients.
col.boundary	Color of boundary coefficient lines.
X.xtick.at	Vector specifying the extreme tick mark locations and the number of intervals between those extreme tick marks on the horizontal axis of the plot of the original times series. This vector takes the form similar to par("xaxp"), and is defaulted to par("xaxp") when X.xtick.at is not specified.
X.ytick.at	Vector specifying the extreme tick mark locations and the number of intervals between those extreme tick marks on the vertical axis of the plot of the original times series. This vector takes the form similar to par("yaxp"), and is defaulted to par("yaxp") when X.ytick.at is not specified.
Stack.xtick.at	Vector of form similar to X.xtick.at specifying the tick mark locations on the horizontal axis of the stacked plot. This is applicable only if plot.X is FALSE.
Stack.ytick.at	Vector of form similar to X.ytick.at specifying the tick mark locations on the vertical axis of the stacked plot. This is applicable only if plot.X is FALSE.
X.xlab	String specifying the label of the horizontal axis of the plot of the original time series.
y.rlabs	Logical flag indicating whether to draw the vertical labels on the right vertical axis of the stacked plot. These labels indicate the number of boundary coefficients to the right of the right boundary line, and the level of decomposition of the wavelet (or scaling) coefficients.
plot.X	Logical flag indicating whether to draw original time series.
plot.W	Logical flag indicating whether to draw the wavelet coefficients in the stacked plot.
plot.V	Logical flag indicating whether to draw the scaling coefficients in the stacked plot.
...	Additional paramters that are acceptable arguments to the generic plot function

Details

plot.dwt plots the DWT wavelet and scaling coefficients. The type parameter species the type of plot, which is currently only stack. If the DWT object is defined for multiple time series, only the data pertaining to the first time series of the DWT object is plotted. Thus, only the wavelet coefficients and scaling coefficients of the first time series of the DWT object will be plotted.

If a single number is specified for levels, then the wavelet coefficients of levels 1 through levels will be plotted. Otherwise, a vector or the first element of a list will specify which levels of the wavelet coefficients will be plotted. Unless specified in the second element of a list, only one level of scaling coefficients will be plotted and this level is equal to the highest level of the wavelet coefficients plotted.

For each respective axis, the distance between a tick mark on the plot of the original time series is equivalent to the distance between a tick mark on the stacked plot. Thus, when altering the relative spacing of the tick marks on the plot of the original time series using X.xtick.at or X.ytick.at, the tick marks of the stacked plot are automatically adjusted. If the plot of the original time series is not drawn, then the user can alter the spacing of the tick marks using Stack.xtick.at and Stack.ytick.at for the horizontal and vertical axes, respectively.

One of plot.W or plot.V must be TRUE.

Author(s)

Kelvin Ma, [e-mail]

References

Percival, D. B. and A. T. Walden (2000) Wavelet Methods for Time Series Analysis, Cambridge University Press.

See Also

stackplot

Examples

X <- rnorm(2048)
dwtobj <- dwt(X)

# Plotting wavelet coefficients of levels 1 through 6 and scaling
# coefficients of level 6.
plot.dwt(dwtobj, levels = 6)

# Plotting wavelet coefficients of levels 1, 3, 5, and scaling
# coefficients of levels 4 and 5, and green boundary coefficient lines.
plot.dwt(dwtobj, levels = list(c(1,3,5),c(4,5)), draw.boundary = TRUE,
col.boundary = "green")

# Plotting wavelet coefficients of level 1 through 6 and not plotting
# any scaling coefficients.
plot.dwt(dwtobj, levels = 6, plot.V = FALSE)

Example output

wavelets documentation built on March 26, 2020, 6:50 p.m.