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Set reference for test sounds

Source: R/set_reference_sounds.R
set_reference_sounds.Rd

set_reference_sounds set rows to be used as reference for each test sound.

Usage

set_reference_sounds(
  X,
  method = getOption("method", 1),
  cores = getOption("mc.cores", 1),
  pb = getOption("pb", TRUE),
  path = getOption("sound.files.path", ".")
)

Arguments

X

Object of class 'data.frame', 'selection_table' or 'extended_selection_table' (the last 2 classes are created by the function selection_table from the warbleR package) with the reference to the test sounds . Must contain the following columns: 1) "sound.files": name of the .wav files, 2) "selec": unique selection identifier (within a sound file), 3) "start": start time and 4) "end": end time of selections, 5) "bottom.freq": low frequency for bandpass, 6) "top.freq": high frequency for bandpass, 7) "sound.id": ID of sounds used to identify counterparts across distances (and transects if more than 1) and 8) "distance": distance (numeric) at which each test sound was re-recorded. A 'transect' column labeling those sounds recorded in the same transect is required if 'method = 2'. 'X' can only have 1 copy for any given sound id in a distance or a transect-distance combination (if column 'transect' is supplied). In addition, 'selec' column values in 'X' cannot be duplicated within a sound file ('sound.files' column) as this combination is used to refer to specific rows in the output 'reference' column.

method

Integer vector of length 1 to indicate the 'experimental design' for measuring degradation. Two methods are available:

  • 1: compare sounds (by 'sound.id') with their counterpart that was recorded at the closest distance to source (e.g. compare sounds recorded at 5m, 10m and 15m with its counterpart recorded at 1m). This is the default method. The function will try to use references from the same transect. However, if there is another test sound from the same 'sound.id' at a shorter distance in other transects, it will be used as reference instead. This behavior aims to account for the fact that in this type of experiments reference sounds are typically recorded at 1 m and at single transect.

  • 2: compare all sounds with their counterpart recorded at the distance immediately before within a transect (e.g. a sound recorded at 10m compared with the same sound recorded at 5m, then sound recorded at 15m compared with same sound recorded at 10m and so on). 'transect' column in 'X' is required.

Can be set globally for the current R session via the "method" option (see options).

cores

Numeric vector of length 1. Controls whether parallel computing is applied by specifying the number of cores to be used. Default is 1 (i.e. no parallel computing). Can be set globally for the current R session via the "mc.cores" option (see options).

pb

Logical argument to control if progress bar is shown. Default is TRUE. Can be set globally for the current R session via the "pb" option (see options).

path

Character string containing the directory path where the sound files are found. Only needed when 'X' is not an extended selection table. If not supplied the current working directory is used. Can be set globally for the current R session via the "sound.files.path" option (see options).

Value

An object similar to 'X' with one additional column, 'reference', with the ID of the sounds to be used as reference by degradation-quantifying functions in downstream analyses. The ID is created as paste(X$sound.files, X$selec, sep = "-").

Details

This function adds a 'reference' column defining which sounds will be used by other functions as reference. Two methods are available (see 'methods' argument description). For method 1 the function will attempt to use re-recorded sounds from the shortest distance in the same transect as reference. However, if there is another re-recorded sound from the same 'sound.id' at a shorter distance in other transects, it will be used as reference instead. This behavior aims to account for the fact that in this type of experiments reference sounds are typically recorded at 1 m and at single transect. Note that if users want to define their own reference sound this can be set manually. If so, NAs must be used to indicate rows to be ignored. References must be indicated as a the combination of the 'sound.files' and 'selec' column. For instance, '10m.wav-1' indicates that the row in which the 'selec' column is '1' and the sound file is '10m.wav' should be used as reference. The function also checks that the information 'X' is in the right format so it wont produce errors in downstream analysis (see 'X' argument description for details on format). The function will ignore rows in which the column 'sound.id' is equals to 'ambient', 'start_marker' or 'end_marker'.

References

Araya-Salas, M., & Smith-Vidaurre, G. (2017). warbleR: An R package to streamline analysis of animal acoustic signals. Methods in Ecology and Evolution, 8(2), 184-191.

See also

check_sound_files, check_sels

Other quantify degradation: blur_ratio(), detection_distance(), envelope_correlation(), plot_blur_ratio(), plot_degradation(), signal_to_noise_ratio(), spcc(), spectrum_blur_ratio(), spectrum_correlation(), tail_to_signal_ratio()

Author

Marcelo Araya-Salas (marcelo.araya@ucr.ac.cr)

Examples

{
  # load example data
  data("test_sounds_est")

# save wav file examples
X <- test_sounds_est[test_sounds_est$sound.files != "master.wav", ]

# method 1
Y <- set_reference_sounds(X = X)

# method 2
Y <- set_reference_sounds(X = X, method = 2)
}