fft_metrics: Discrete Fourier Transform Metrics
In discharge: Fourier Analysis of Discharge Data

Description Usage Arguments Value Examples

This is a wrapper function to calculate all the DFFT metrics for the given input signal

1 2	fft_metrics(data, candmin, candmax, river.name = "", baseline.signal = NULL)

`data`	A matrix with dates in the first column and discharge values in the second column. Dates should be of the format "YYYY-MM-DD"
`candmin`	numeric vector of possible ordinal days in which the predicted signal is lowest. This range need not be narrow, but a string of consecutive days should not include more than only local minimum. Used for calculating the high- and low-flow windows
`candmax`	numeric vector of possible ordinal days in which the predicted signal is highest. This range need not be narrow, but a string of consecutive days should not include more than only local maximum.
`river.name`	A character vector listing the river name.
`baseline.signal`	If `NULL`, this function calculates baseline.signal using fourierAnalysis over the entire input series. The baseline signal can also be explicitly calculated and passed in as parameter. Check function `prepareBaseline()`

A list containing 2 data frames:

`high.level.metrics`	Data frame containing NAA and FPExt values for each year in the given series
`naa.shape.components`	Data frame containing HSAM, LSAM, Transition time, HSAF, LSAF, timing of HSAM, timing of LSAM, IFI, IDI

# load sample data
data("sycamore")
x = sycamore

# get streamflow object for the sample data
x.streamflow = asStreamflow(x)

# prepare baseline signal 
x.bl = prepareBaseline(x.streamflow)

# fetch the DFFT metrics for this sample data
# "candmax" chosen because preliminary analysis (e.g. with fourierAnalysis 
#           output) shows the signal is highest sometime between
#           day 190 and day 330
# "candmin" can be estimated analogously.
x.fftmetrics = fft_metrics(x, river.name = "Sycamore", candmin = c(40:125), 
                           candmax = c(190:330), baseline.signal = x.bl)