photobiology: get_peaks – R documentation

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get_peaks

Get peaks and valleys in a spectrum

Description

These functions find peaks (local maxima) or valleys (local minima) in a spectrum, using a user selectable size threshold relative to the tallest peak (global maximum). This a wrapper built on top of function peaks from package splus2R.

Usage

get_peaks(
  x,
  y,
  ignore_threshold = 0,
  span = 5,
  strict = TRUE,
  x_unit = "",
  x_digits = 3,
  na.rm = FALSE
)

get_valleys(
  x,
  y,
  ignore_threshold = 0,
  span = 5,
  strict = TRUE,
  x_unit = "",
  x_digits = 3,
  na.rm = FALSE
)

Arguments

`x`	numeric
`y`	numeric
`ignore_threshold`	numeric Value between 0.0 and 1.0 indicating the relative size compared to tallest peak threshold below which peaks will be ignored. Negative values set a threshold so that the tallest peaks are ignored, instead of the shortest.
`span`	integer A peak is defined as an element in a sequence which is greater than all other elements within a window of width `span` centered at that element. Use `NULL` for the global peak.
`strict`	logical If `TRUE`, an element must be strictly greater than all other values in its window to be considered a peak.
`x_unit`	character Vector of texts to be pasted at end of labels built from x value at peaks.
`x_digits`	numeric Number of significant digits in wavelength label.
`na.rm`	logical indicating whether `NA` values should be stripped before searching for peaks.

Value

A data frame with variables w.length and s.irrad with their values at the peaks or valleys plus a character variable of labels.

Examples

with(sun.spct, get_peaks(w.length, s.e.irrad))
with(sun.spct, get_valleys(w.length, s.e.irrad))

photobiology

Photobiological Calculations

v0.10.10

GPL (>= 2)

Authors

Pedro J. Aphalo [aut, cre] (<https://orcid.org/0000-0003-3385-972X>), Titta K. Kotilainen [ctb] (<https://orcid.org/0000-0002-2822-9734>), Glenn Davis [ctb], Agnese Fazio [ctb]

Initial release

2022-03-24