state {SiMRiv}

Define a movement state

Description

Defines a behavioral state to be used when creating species.

Usage

  state(concentration, pwind = perceptualRange("circular", 0)
    , steplen = 1, name = "")
  state.Resting()    # still state
  state.RW()         # uniform random walk (brownian motion),
                     # independent of resistance
  state.CRW(concentration)  # correlated random walk,
                          # independent of resistance

Arguments

concentration

turning angle concentration, a value between 0 (uniform distribution resulting in random walk) and 1 (only one value possible resulting in a straight line path)

pwind

a perceptualRange definition

steplen

the base (maximum) step length of this state in map units. Note that the actual step length depends on the resistance in each step.

name

the name of the state

Details

See Arith-methods for more convenient ways of setting parameters, instead of using state.

Value

An object of class state.

Note

The perceptual range radius and step length must be adequate to the resolution of the resistance raster (if provided in simulations). If no raster will be provided, then the perceptual range is irrelevant, and the step length has solely a relative meaning (in relation to other states or other species).

For a review of different random walks, see Codling et al. (2008)

References

• Codling, E. A., Plank, M. J., & Benhamou, S. 2008. Random walk models in biology. Journal of the Royal Society Interface, 5(25), 813-834.

See Also

species, perceptualRange, Arith-methods.

Examples

## a correlated random walk influenced by landscape

state(0.97, perceptualRange("cir", 500), 10, "CorrelatedRW")

## the same, but using the shortcut form

state.CRW(0.97) * 500 + 10