COI function

Computation of the cone of influence

Wavelet transformation of a time series includes padding with zeros at the edges. This function determines the spectrum borders influenced by edge effects.

This code has been developed by Huidong Tian (archived R package WaveletCo).

COI(start = start, dt = dt, nc = nc, nr = nr, Period = Period)

Arguments

• start: starting point in time. Default: start = 1.

• dt: time resolution, i.e. sampling resolution in the time domain, 1/dt = number of observations per time unit

• nc: number of columns = number of observations = number of observation epochs; "epoch" meaning point in time

• nr: number of rows = number of scales (Fourier periods)

• Period: the Fourier periods (measured in time units determined by dt)

Returns

a list with the following elements:

	x , y	:	coordinates of the cone of influence
	axis.1	:	tick levels corresponding to the time steps
			used for wavelet transformation:
			1, 1+dt, 1+2dt, ... if start = 1
	axis.2	:	tick levels corresponding to the log of Fourier periods:
			log2(Period)

References

Tian, H., and Cazelles, B., 2012. WaveletCo. Available at https://cran.r-project.org/src/contrib/Archive/WaveletCo/, archived April 2013; accessed July 26, 2013.

Author(s)

Code developed by Huidong Tian.

See Also

analyze.wavelet, analyze.coherency, wt.image, wc.image