track_period_wavelet {WaverideR}

Track the period of a cycle in a wavelet spectra

Description

Interactively select points in a wavelet spectra to trace a period in a wavelet spectra. The track_period_wavelet function plots a wavelet spectra in which spectral peaks can selected allowing one to track a ridge hence one can track the a cycle with a changing period. Tracking points can be selected in the Interactive interface and will be shown as white dots when one wants to deselect a point the white dots can be re-clicked/re-selected and will turn red which indicates that the previously selected point is deselected. Deselecting points can be quite tricky due to the close spacing of points and such the delpts_tracked_period_wt can be used to delete points were previously selected using the track_period_wavelet function.

Usage

track_period_wavelet(
  astro_cycle = 405,
  wavelet = NULL,
  n.levels = 100,
  track_peaks = TRUE,
  periodlab = "Period (metres)",
  x_lab = "depth (metres)",
  palette_name = "rainbow",
  color_brewer = "grDevices",
  plot_horizontal = TRUE
)

Arguments

astro_cycle

Duration (in kyr) of the cycle which traced.

wavelet

Wavelet object created using the analyze_wavelet function.

n.levels

Number of color levels Default=100.

track_peaks

Setting which indicates whether tracking is restricted to spectral peaks (track_peaks=TRUE) or whether any point within the wavelet spectra can be selected (track_peaks=FALSE) Default=TRUE.

periodlab

label for the y-axis Default="Period (metres)".

x_lab

label for the x-axis Default="depth (metres)".

palette_name

Name of the color palette which is used for plotting. The color palettes than can be chosen depends on which the R package is specified in the color_brewer parameter. The included R packages from which palettes can be chosen from are; the 'RColorBrewer', 'grDevices', 'ColorRamps' and 'Viridis' R packages. There are many options to choose from so please read the documentation of these packages Default=rainbow. The R package 'viridis' has the color palette options: “magma”, “plasma”, “inferno”, “viridis”, “mako”, and “rocket” and “turbo” To see the color palette options of the The R pacakge 'RColorBrewer' run the RColorBrewer::brewer.pal.info() function The R package 'colorRamps' has the color palette options:"blue2green", "blue2green2red", "blue2red", "blue2yellow", "colorRamps", "cyan2yellow", "green2red", "magenta2green", "matlab.like", "matlab.like2" and "ygobb" The R package 'grDevices' has the built in palette options:"rainbow", "heat.colors", "terrain.colors","topo.colors" and "cm.colors" To see even more color palette options of the The R pacakge 'grDevices' run the grDevices::hcl.pals() function

color_brewer

Name of the R package from which the color palette is chosen from. The included R packages from which palettes can be chosen are; the RColorBrewer, grDevices, ColorRamps and Viridis R packages. There are many options to choose from so please read the documentation of these packages. "Default=grDevices

plot_horizontal

plot the wavelet horizontal or vertical eg y axis is depth or y axis power Default=TRUE

Value

Results of the tracking of a cycle in the wavelet spectra is a matrix with 3 columns. The first column is depth/time The second column is the period of the tracked cycle The third column is the sedimentation rate based on the duration (in time) of the tracked cycle

Author(s)

The function is based/inspired on the traceFreq function of the 'astrochron' R package

References

Routines for astrochronologic testing, astronomical time scale construction, and time series analysis <doi:10.1016/j.earscirev.2018.11.015>

Examples

#Track the 405kyr eccentricity cycle in the magnetic susceptibility record
# of the Sullivan core of Pas et al., (2018)

mag_wt <- analyze_wavelet(data = mag,
dj = 1/100,
lowerPeriod = 0.1,
upperPeriod = 254,
verbose = FALSE,
omega_nr = 10)

mag_track <- track_period_wavelet(astro_cycle = 405,
                                  wavelet=mag_wt,
                                  n.levels = 100,
                                  track_peaks=TRUE,
                                  periodlab = "Period (metres)",
                                  x_lab = "depth (metres)",
                                 palette_name = "rainbow",
                                 color_brewer="grDevices",
                                 plot_horizontal=TRUE)