warbleR (version 1.1.26)

selection_table: Create 'selection_table' and 'extended_selection_table' objects

Description

selection_table converts data frames into an object of classes 'selection_table' or 'extended_selection_table'.

Usage

selection_table(X, max.dur = 10, path = NULL, whole.recs = FALSE,
extended = FALSE, confirm.extended = TRUE, mar = 0.1, by.song = NULL, 
pb = TRUE, parallel = 1, ...)

Arguments

X

data frame with 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. Columns for 'top.freq', 'bottom.freq' and 'channel' are optional. Note that, when 'channel' is not provided the first channel (i.e. left channel) would be used by default. Frequency parameters (including top and bottom frequency) should be provided in kHz. Alternatively, a 'selection_table' class object can be input to double check selections. The output of auto_detec can be used as the input object for other warbleR functions.

max.dur

the maximum duration of expected for a selection (ie. end - start). If surpassed then an error message will be generated. Useful for detecting errors in selection tables.

path

Character string containing the directory path where the sound files are located. If NULL (default) then the current working directory is used.

whole.recs

Logical. If TRUE the function will create a selection table for all sound files in the working directory (or "path") with `start = 0` and `end = duration_wavs()`. Default is if FALSE. Note that this will not create a extended selection table. If provided 'X' is ignored.

extended

Logical. If TRUE, the function will create an object of class 'extended_selection_table' which included the wave objects of the selections as an additional attribute ('wave.objects') to the data set. This is and self-contained format that does not require the original sound files for running most acoustic analysis in warbleR. This can largely facilitate the storing and sharing of (bio)acoustic data. Default is if FALSE. An extended selection table won't be created if there is any issue with the selection. See 'details'.

confirm.extended

Logical. If TRUE then the size of the 'extended_selection_table' will be estimated and the user will be asked for confirmation (in the console) before proceeding. Ignored if 'extended' is FALSE. This is used to prevent generating objects too big to be dealt with by R. See 'details' for more information about extended selection table size.

mar

Numeric vector of length 1 specifying the margins (in seconds) adjacent to the start and end points of the selections when creating extended selection tables. Default is 0.1. Ignored if 'extended' is FALSE.

by.song

Character string with the column name containing song labels. If provided a wave object containing for all selection belonging to a single song would be saved in the extended selection table (hence only applicable for extended selection tables). Note that the function assumes that song labels are not repeated within a sound file. If NULL (default), wave objects are created for each selection (e.g. by selection). Ignored if extended = FALSE.

pb

Logical argument to control progress bar and messages. Default is TRUE.

parallel

Numeric. Controls whether parallel computing is applied. It specifies the number of cores to be used. Default is 1 (i.e. no parallel computing).

...

Additional arguments to be passed to check_sels for customizing checking routine.

Value

An object of class selection_table which includes the original data frame plus the following additional attributes:

• 1) A data frame with the output of check_sels run on the input data frame. If a extended selection table is created it will also include the original values in the input data frame for each selections. This are used by downstream warbleR functions to improve efficiency and avoid errors due to missing or mislabeled data, or selection out of the ranges of the original sound files.

• 2) A list indicating if the selection table has been created by song (see 'by.song argument).

• 3) If a extended selection table is created a list containing the wave objects for each selection (or song if 'by.song').

Details

This function creates and object of class 'selection_table' or 'extended_selection_table' (if extended = TRUE, see below). First, the function checks:

• 1) if the selections listed in the data frame correspond to .wav files in the working directory

• 2) if the sound files can be read and if so,

• 3) if the start and end time of the selections are found within the duration of the sound files

If no errors are found the a selection table or extended selection table will be generated. Note that the sound files should be in the working directory (or the directory provided in 'path'). This is useful for avoiding errors in downstream functions (e.g. spectro_analysis, cross_correlation, catalog, freq_DTW). Note also that corrupt files can be fixed using fix_wavs ('sox' must be installed to be able to run this function). The 'selection_table' class can be input in subsequent functions.

When extended = TRUE the function will generate an object of class 'extended_selection_table' which will also contains the wave objects for each of the selections in the data frame. This transforms selection tables into self-contained objects as they no longer need the original sound files to run acoustic analysis. This can largely facilitate the storing and sharing of (bio)acoustic data. Extended selection table size will be a function of the number of selections nrow(X), sampling rate, selection duration and margin duration. As a guide, a selection table with 1000 selections similar to the ones in 'lbh_selec_table' (mean duration ~0.15 seconds) at 22.5 kHz sampling rate and the default margin (mar = 0.1) will generate a extended selection table of ~31 MB (~310 MB for a 10000 rows selection table). You can check the size of the output extended selection table with the object.size function. Note that extended selection table created 'by.song' could be considerable larger.

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_wavs, blog post on extended selection tables

Examples

# NOT RUN {
{
data(list = c("Phae.long1", "Phae.long2", "Phae.long3", "Phae.long4", 
"lbh_selec_table"))
writeWave(Phae.long1, file.path(tempdir(), "Phae.long1.wav"))
writeWave(Phae.long2, file.path(tempdir(), "Phae.long2.wav"))
writeWave(Phae.long3, file.path(tempdir(), "Phae.long3.wav"))
writeWave(Phae.long4, file.path(tempdir(), "Phae.long4.wav"))

# make selection table
st <- selection_table(X = lbh_selec_table, path = tempdir())

is_selection_table(st)

#' # make extended selection table
st <- selection_table(X = lbh_selec_table, extended = TRUE, 
confirm.extended = FALSE, 
path = tempdir())

is_extended_selection_table(st)

### make extended selection by song  
# create a song variable
lbh_selec_table$song <- as.numeric(lbh_selec_table$sound.files)

st <- selection_table(X = lbh_selec_table, extended = TRUE, 
confirm.extended = FALSE, by.song = "song", path = tempdir())
}

# }