Sample a connected patch of cells within an image

patch_subsample(
  cells,
  k.cells = NULL,
  k.pavement = NULL,
  k.stomata = NULL,
  plot.patch = FALSE,
  seed = NULL,
  stom.val = 85,
  subs.val = 170,
  pave.val = 255
)

Arguments

cells: SpatialPolygonsDataFrame of all cells, with edge cells removed.
k.cells: Numeric. Desired number of cells to be sampled in patch
k.pavement: Numeric. Desired number of pavement cells to be sampled in patch
k.stomata: Numeric. Desired number of stomata to be sampled in patch
plot.patch: Logical. Plot the sampling iterations? Defaults to FALSE.
seed: Numeric. For reproducibility, the starting cell can be set using this argument.
stom.val: Numeric vector of length 1. The value of stomatal cells (guard cells + pore)
subs.val: Numeric vector of length 1. The value of subsidiary cells
pave.val: Numeric vector of length 1. The value of pavement cells

Value

A numeric vector containing the indices of the sampled polygons

Details

If setting a seed using the seed argument, cell numbers can be displayed on a plot of the cells using: text(cells, labels = 1:length(cells)).

Examples

if (FALSE)  #
#minimum patch size of 40 cells
patch_subsample(cells, k.cells=40)
#patch must include at least 10 stomatal complexes and 30 pavement cells
patch_subsample(cells,k.pavement=30, k.stomata=10)
#> NULL