Make camera trap grids

Set up grids around focal points. For example, sample points in your study area with sample_ct() then use grid_ct() to establish a grid of camera traps around each.

Usage

grid_ct(features, distance, case, n, id = "id_sample_ct")

Arguments

features

sf features (see sf::st_sf())

distance

distance between adjacent camera traps. Don't worry about the hypotenuse.

case

"queen", "rook", "bishop", or "triplet". Ignored if n is provided.

n

number of points around each focal point. n overrides the case argument, do not provide both - see Details.

id

default: "id_sample_ct" generated automatically from sample_ct()

Value

Extended sf object either nine times the length of input features for 'queen' case or 5 times the length of input DT for 'rook' or 'bishop' case. Otherwise n * number the length of input features. See examples.

The logical 'focal' column indicates which point is the focal camera trap for each grid.

See also

Other grid: grid_design()

Examples

data("clearwater_lake_density")
pts <- sample_ct(clearwater_lake_density, 1, type = 'random')

# Make grid with case, eg. 'queen'
queen <- grid_ct(features = pts, distance = 100, case = 'queen')

# Plot
plot(queen['focal'])


# Make grid with n
n_grid <- grid_ct(features = pts, distance = 100, n = 25)
plot(n_grid['id_grid_ct'])