banter (version 0.9.6)

subsampleDetections: Subsample Detections

Description

Extract a random subsample of detections for each event and detector.

Usage

subsampleDetections(data, n)

Value

a detector data.frame or list of detector data.frames with no more than n detections per event per detector.

Arguments

data

a detector data.frame or list of detector data.frames.

n

a value giving the number (n >= 1) or fraction (n between 0 and 1) of detections per event per detector to select. Detections are randomly selected without replacement. If n is greater than the number of detections in an event, all detections for that event will be retained.

Author

Eric Archer

References

Rankin, S., Archer, F., Keating, J. L., Oswald, J. N., Oswald, M. , Curtis, A. and Barlow, J. (2017), Acoustic classification of dolphins in the California Current using whistles, echolocation clicks, and burst pulses. Marine Mammal Science 33:520-540. doi:10.1111/mms.12381

Examples

data(train.data)

# initial number of detections per event per detector
sapply(train.data$detectors, function(x) table(x$event.id))

# select half of all detectors
detect.half <- subsampleDetections(train.data$detectors, 0.5)
sapply(detect.half, function(x) table(x$event.id))

# select 20 detections
detect.20 <- subsampleDetections(train.data$detectors, 20)
sapply(detect.20, function(x) table(x$event.id))

# select 10 detections fro 'ec' detector
ec.10 <- subsampleDetections(train.data$detectors$ec, 10)
table(ec.10$event.id)