move (version 4.2.5)

brownian.motion.variance.dyn: Calculates the dynamic brownian motion variance

Description

A function to calculate the dynamic brownian motion variance for a movement track. It can be also used by advanced programmers to program against.

Usage

# S4 method for .MoveTrackSingle,numeric,numeric,numeric
brownian.motion.variance.dyn(object, location.error, window.size, margin)

Value

'dBMvariance' object, if move object is provided

'dBMvarianceStack' object, if moveStack object is provided

'dBMvarianceBurst' object, if moveBurst object is provided

Arguments

object

a move, moveStack or moveBurst object can be used for variance calculation. This object must be in a flat coordinate system (projection different to longitude/latitude), use spTransform to transform your coordinates.

location.error

single numeric value or vector of the length of coordinates that describes the error of the location (sender/receiver) system in map units.

window.size

The size of the moving window along the track for the variance calculation. Larger windows provide more stable/accurate estimates of the brownian motion variance but are less well able to capture more frequent changes in behavior. This number has to be odd.

margin

The margin size used for variance calculation. This number has to be odd.

Author

Bart Kranstauber & Anne Scharf

References

Kranstauber, B., Kays, R., LaPoint, S. D., Wikelski, M. and Safi, K. (2012), A dynamic Brownian bridge movement model to estimate utilization distributions for heterogeneous animal movement. Journal of Animal Ecology. doi: 10.1111/j.1365-2656.2012.01955.x

See Also

brownian.bridge.dyn, dynBGBvariance

Examples

data(leroy)
data2 <- spTransform(leroy[1:80,], CRSobj="+proj=aeqd +ellps=WGS84", center=TRUE)
err<-rep(23.5,n.locs(data2))
dBMvar <- brownian.motion.variance.dyn(data2, location.error=err, margin=13, window.siz=31)
dBMvar