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Identify potential next positions

potential_position_func.Rd

The function generates a bunch of potential positions to choose the next step from. Positions are generated based on provided bearing (Von Mises distribution) and step distributions (Gamma distribution). For each position, the value of resource_layer is retrieved as well as the distance from the colony location.

Usage

potential_position_func(
  n,
  bearing,
  step,
  from,
  colony_location,
  resource_layer
)

Arguments

n

Numeric, the number of potential positions to generate

bearing

Numeric vector, mu and kappa to be passed on randomdir

step

Numeric, shape and rate to be passed on randomdist

from

data.frame including Lon and Lat fields and stepID of the point of origin

colony_location

data.frame vector with lon and lat position of the colony

resource_layer

SpatRaster, the suitability or any resource layer to be used to sort potential position (a single layer)

Value

A data.frame with the n potential positions from the point of origin, informed with the value of the provided environmental layer corresponding to each as well as the distance from the colony.

See also

Other individual movement functions: randomdir(), randomdist(), simulate_trajectory_CPF(), simulate_trajectory_FR()

Examples

from <- data.frame(Lon = 1, Lat = 2, toto = 5)
colony_location <- data.frame(Lon = 2, Lat = 5)
cdt <- generate_env_layer(grid = create_grid(), n = 1)$rasters
#> [using unconditional Gaussian simulation]
potential_position_func(n = 10, from = from, 
                        colony_location = colony_location, resource_layer = cdt, 
                        bearing = c(90,10), step = c(4.5, 3))
#>        angle      step        Lon       Lat       env dist_col
#> 1  124.54851 1.3176841  1.5797831 0.8167237 0.5954073 4.204329
#> 2   38.59724 1.5516632  1.9668066 3.2136489 0.5617037 1.786659
#> 3  317.19460 1.2513320 -0.2442748 2.1327102 0.6177145 3.641170
#> 4  185.32546 0.7604406  0.2398684 2.0216779 0.6177145 3.459547
#> 5   57.06428 0.5626446  1.4894966 2.2774203 0.5421721 2.770028
#> 6  208.31050 0.9354868  1.5323879 2.7692196 0.5329122 2.279264
#> 7  190.77661 3.2482543 -1.1179400 4.4628207        NA 3.163876
#> 8  180.25368 1.2824369  0.5149331 0.8128377 0.6540463 4.442719
#> 9   22.63236 0.2880789  0.7691424 1.8276799 0.5297902 3.402738
#> 10 111.86924 0.8619650  1.2896450 1.1881568 0.5954073 3.877467
#>    potential_position_id
#> 1                      1
#> 2                      2
#> 3                      3
#> 4                      4
#> 5                      5
#> 6                      6
#> 7                      7
#> 8                      8
#> 9                      9
#> 10                    10