gridUncertaintyRandom {redlistr}

Function to compute AOO with grid uncertainty randomly with stop rule

Description

gridUncertaintyRandom helps determine the minimum number of area of occupancy (AOO) grid cells occupied by a species or ecosystem. It varies the location of the AOO grid by shifting in randomly in both x- and y- axes, returning summary statistics for the range of AOOs calculated, and the RasterLayer(s) containing the grids with the minimum AOO. It automatically stops when the AOO no longer improves after a specified number of rounds.

Usage

gridUncertaintyRandom(
  input.data,
  grid.size,
  n.AOO.improvement,
  min.percent.rule = FALSE,
  percent = 1,
  max.n.rounds = 1000
)

Arguments

input.data

Spatial object of an ecosystem or species distribution. Please use a CRS with units measured in metres.

grid.size

A number specifying the width of the desired grid square (in same units as your coordinate reference system)

n.AOO.improvement

Specifies the minimum number of rounds the calculated AOO is not improved before stopping the function.

min.percent.rule

Logical. If TRUE, a minimum area threshold must be passed before a grid is counted as an AOO grid.

percent

Numeric. The minimum percent to be applied as a threshold for the min.percent.rule.

max.n.rounds

Specifies the maximum number of rounds to calculate AOOs. Generally unused except to limit computation time.

Value

List containing the following:

• Data frame of summary statistics for the results

• Data frame showing the distance shifted in x and y directions used to create the AOO grid(s) and their associated AOOs

• List of RasterLayer(s) containing the AOO grid(s) which return the smallest AOO

Author(s)

Calvin Lee [e-mail]. Nicholas Murray [e-mail]

See Also

createGrid() getAOOSilent()

Other gridUncertainty functions: gridUncertaintyBase(), gridUncertaintyRandomManual(), gridUncertaintyRestricted(), gridUncertaintySimulation(), gridUncertainty()

Examples

crs.UTM55S <- '+proj=utm +zone=55 +south +ellps=WGS84 +datum=WGS84 +units=m +no_defs'
r1 <- raster(ifelse((volcano<130), NA, 1), crs = crs.UTM55S)
extent(r1) <- extent(0, 6100, 0, 8700)
x <- gridUncertaintyRandom(r1, grid.size = 1000, n.AOO.improvement = 50,
                           min.percent.rule = TRUE, percent = 1)