makeClass: Create a class of patches.

In landscapeR: Categorical Landscape Simulation Facility

Create a class of patches.

Description

Create a class of patches.

Usage

makeClass(
  context,
  npatch,
  size,
  pts = NULL,
  bgr = 0,
  edge = FALSE,
  rast = TRUE,
  val = 1
)

Arguments

context	SpatRaster object, a raster of an empty landscape or a mask, indicating where the patch cannot be generated (see bgr argument).
npatch	number of patches per class
size	integer. The size of patches, as number of raster cells. A single integer can be provided, in which case all patches will have that size.
pts	integer or matrix. The seed point location around which the patches are built (random points are given by default). It can be an integer, as indexes of the cells in the raster, or a two columns matrix indicating x and y coordinates.
bgr	integer. A single value of background cells, where a patch can be generated (default is zero). Cells/classes which cannot be changed must have a different value.
edge	logical. Should the vector of edge cells of the patch be returned?
rast	logical. If TRUE returns a SpatRaster object, otherwise a vector of cell numbers where the patch occurs
val	integer. The value to be assigned to patch cells, when rast=TRUE

Details

The patches created can be contiguous, therefore resembling a single patch with size equal to the sum of contiguous cells. The patches are created starting from the seed points (if provided) and iteratively sampling randomly neighbouring cells at the edge of the patch, according to von Neumann neighbourhood (four cells, aka Rook case). There is a tolerance of +/- 3 cells from the patch size declared in size argument.

Value

A SpatRaster object, or a vector of cell numbers if rast=FALSE.

Examples

library(terra)
mtx = matrix(0, 33, 33)
r = rast(mtx)
ext(r) = c(0, 10, 0, 10)
num = 5
size = 15
rr = makeClass(r, num, size)
plot(rr)

## Create a class of three patches of given size at three corners of the spatial context
size = c(10, 50, 200)
pts = c(1, 33, 1089)
rr = makeClass(r, 3, size, pts)
plot(rr)

landscapeR documentation built on Nov. 2, 2024, 1:07 a.m.