move (version 4.2.5)

dynBGBvariance: Calculates the Bivariate Gaussian Bridge motion variance

Description

A function to calculate the dynamic Bivariate Gaussian Bridge orthogonal and parallel variance for a movement track

Usage

dynBGBvariance(move, locErr, margin, windowSize,...)

Value

a dBGBvariance-class object

Arguments

move

a move object. This object must be in a projection different to longitude/latitude, use spTransform to transform your coordinates.

locErr

single numeric value or vector of the length of coordinates that describes the error of the location (sender/receiver) system in map units. Or a character string with the name of the column containing the location error can be provided.

margin

The margin used for the behavioral change point analysis. This number has to be odd.

windowSize

The size of the moving window along the track. 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.

...

Additional arguments

Author

Bart Kranstauber & Anne Scharf

Details

The function uses windowApply with the BGBvarbreak function in order to implement a dynamic calculation of the variance

References

Kranstauber, B., Safi, K., Bartumeus, F.. (2014), Bivariate Gaussian bridges: directional factorization of diffusion in Brownian bridge models. Movement Ecology 2:5. doi:10.1186/2051-3933-2-5.

See Also

dynBGB, brownian.motion.variance.dyn

Examples

data(leroy)
leroy <- leroy[230:265,]

## change projection method to aeqd and center the coordinate system to the track
dataAeqd <- spTransform(leroy, CRSobj="+proj=aeqd +ellps=WGS84", center=TRUE)

dBGBvar <- dynBGBvariance(dataAeqd, locErr=9, windowSize=31, margin=15)
dBGBvar