falseDetect: Identify false or spurious detections in acoustic telemetry...

In aspillaga/fishtrack3d: Analysis of Passive Acoustic Telemetry Data in 3D

Description

False detections are defined as single detections within a predefined time interval (usually 24h). They can be identified among all the detections of the whole acoustic array or individually (providing the receiver argument), in which case the the detections of each single acoustic receiver are considered independently.

Usage

falseDetect(tag.id, time.stamp, rec.id = NULL, time.int = 24)

Arguments

tag.id	vector with the ID codes of tagged individuals.
time.stamp	vector with the date and time of each detection in POSIXt format.
rec.id	vector with the ID codes of the receivers for each detection. Optional argument, if provided, the fuction will also identify the false detections within each receiver.
time.int	time interval (in hours) that define false detections. It is set to 24h by default, as it is the most commonly used value.

Value

The function returns a data.frame with one or two logical vectors indicating if each detection has been identified as good (TRUE) or false (FALSE), taking into account the whole detection array (first column) or each receiver separately (optional second column, only if receiver is provided).

Examples

# Create a random dataset
set.seed(900)
time.stamp <- Sys.time() + c(1:24, 70:71, 200, 300:320, 500, 701:720) * 3600
tag.id <- factor(sample(c("i1", "i2"), length(time.stamp), replace = TRUE))
rec.id <- factor(sample(c("r1", "r2"), length(time.stamp), replace = TRUE))

# False detections for the whole receiver array
f1 <- falseDetect(tag.id, time.stamp)
plot(time.stamp, tag.id, pch = (1:2)[rec.id])
points(time.stamp[!f1], tag.id[!f1], col = 2, cex = 2)

# False detections within individual receivers
f2 <- falseDetect(tag.id, time.stamp, rec.id)
plot(time.stamp, tag.id, pch = (1:2)[rec.id])
points(time.stamp[!f2$receiver], tag.id[!f2$receiver], col = 4, cex = 2.4)
points(time.stamp[!f2$array], tag.id[!f2$array], col = 2, cex = 2)

aspillaga/fishtrack3d documentation built on June 4, 2019, 9:14 a.m.