Wrapper for selecting different animal movement methods.
This version uses just turn angles and step lengths to define the correlated random walk.
move(hypothesis = "crw", ...)crw(agent, extent, stepLength, stddev, lonlat, torus = FALSE)
# S4 method for SpatialPointsDataFrame
crw(agent, extent, stepLength, stddev,
lonlat, torus = FALSE)
# S4 method for SpatialPoints
crw(agent, extent, stepLength, stddev, lonlat,
torus = FALSE)
Character vector, length one, indicating which movement
hypothesis/method to test/use. Currently defaults to
'crw' (correlated random walk) using crw
.
arguments passed to the function in hypothesis
A SpatialPoints*
object.
If a SpatialPointsDataFrame
, 2 of the columns must
be x1
and y1
, indicating the previous location.
If a SpatialPoints
object, then x1
and
y1
will be assigned randomly.
An optional Extent
object that will be used for torus
.
Numeric vector of length 1 or number of agents describing step length.
Numeric vector of length 1 or number of agents describing standard deviation of wrapped normal turn angles.
Logical. If TRUE
, coordinates should be in degrees.
If FALSE
coordinates represent planar ('Euclidean')
space (e.g. units of meters)
Logical. Should the crw movement be wrapped to the opposite
side of the map, as determined by the extent
argument.
Default FALSE
.
A SpatialPointsDataFrame object with updated spatial position defined by a single occurence of step length(s) and turn angle(s).
This simple version of a correlated random walk is largely the version that was presented in Turchin 1998, but it was also used with bias modifications in McIntire, Schultz, Crone 2007.
Turchin, P. 1998. Quantitative analysis of movement: measuring and modeling population redistribution in animals and plants. Sinauer Associates, Sunderland, MA.
McIntire, E. J. B., C. B. Schultz, and E. E. Crone. 2007. Designing a network for butterfly habitat restoration: where individuals, populations and landscapes interact. Journal of Applied Ecology 44:725-736.