Skip to contents

Convert a binary valley raster to polygons

Source: R/fl_valley_poly.R
fl_valley_poly.Rd

Polygonizes a binary (0/1) valley raster, returning an sf polygon layer. Valley cells (1) are dissolved into contiguous polygons; non-valley cells are dropped. This is the natural final step after fl_valley_confine().

Usage

fl_valley_poly(x, dissolve = TRUE)

Arguments

x

A SpatRaster with binary values (0/1), typically the output of fl_valley_confine().

dissolve

Logical. If TRUE (default), adjacent valley cells are dissolved into multipolygon features. If FALSE, each contiguous patch is a separate polygon.

Value

An sf polygon object in the CRS of x. Contains a valley column with value 1.

Examples

dem <- terra::rast(system.file("testdata/dem.tif", package = "flooded"))
slope <- terra::rast(system.file("testdata/slope.tif", package = "flooded"))
gentle <- fl_mask(slope, threshold = 9, operator = "<=")
poly <- fl_valley_poly(gentle)
terra::plot(dem, main = "Gentle slopes as polygons")
plot(sf::st_geometry(poly), add = TRUE, col = "#00800040", border = "darkgreen")