Apply a forms_matrix to Positive and Negative Overlooks — forms_matrix

Apply a forms_matrix to Positive and Negative Overlooks

Usage

forms_matrix_apply(
  x,
  rcl = forms_matrix_get(),
  positive = "positive",
  negative = "negative",
  ...
)

Arguments

x: SpatRaster containing two layers with names specified in positive and negative.
rcl: forms_matrix. Matrix to use for classification of x. Rows are "negative" and columns are "positive".
positive: Character. Layer name of positive count. Default: "positive".
negative: Character. Layer name of negative count. Default: "negative".
...: Additional arguments passed to terra::classify().

Value

A SpatRaster containing the classification result.

Examples

library(terra)
#> terra 1.8.54
library(rgeomorphon)

SEARCH = 7       # outer search radius (cells)
SKIP = 1         # inner skip radius (cells)
DIST = 0         # flatness distance (cells)
FLAT = 1         # flat angle threshold
MODE = "anglev1" # comparison mode

## classic volcano
data("volcano", package = "datasets")
dem <- terra::rast(volcano)
terra::crs(dem) <- terra::crs("EPSG:2193")
terra::ext(dem) <- c(1756968, 1757578, 5917000, 5917870)
names(dem) <- "elevation"

res <- geomorphons(
    dem,
    search = SEARCH,
    skip = SKIP,
    dist = DIST,
    flat = FLAT,
    comparison_mode = MODE,
    forms = TRUE,
    ternary = TRUE,
    positive = TRUE,
    negative = TRUE
)

res2 <- terra::rast(lapply(c(4, 5, 6), function(n) {
  geomorphon_theme(
    forms_matrix_apply(
        x = res[[c("positive", "negative")]],
        rcl = forms_matrix_get(n)
    )
  )
}))
names(res2) <- c("forms4", "forms5", "forms6")

terra::plot(c(res, res2))