Add buffered road corridors to an escape-boundary zone

Creates a road-aware escape zone by combining a base escape zone with buffered road/pathway corridors. This is useful for tsunami workflows in coastal cities where bridges, causeways, or other walkways over water can be lost when the inundation layer is split into land and water masks. The resulting object can be passed to find_escape_points() so escape/safety points are generated from a boundary that includes relevant road corridors as well as the tsunami zone.

Usage

make_road_aware_escape_zone(
  escape_zone,
  roads,
  road_buffer_m = 2,
  crop_buffer_m = 3,
  include_base_zone = TRUE
)

Arguments

escape_zone

Base escape-boundary zone, usually the land-inundation-plus- water zone from prepare_tsunami_zones().

roads

Road/pathway network used to create the road-aware corridor.

road_buffer_m

First road buffer distance in map units.

crop_buffer_m

Optional second buffer applied before cropping/combining.

include_base_zone

Logical. If TRUE, combine the buffered roads with the original escape_zone. If FALSE, only the buffered road corridor is returned.

Value

A dissolved SpatVector escape-boundary zone.

Examples

r <- terra::rast(nrows = 4, ncols = 4, xmin = 0, xmax = 4, ymin = 0, ymax = 4,
  vals = 1, crs = "EPSG:3857")
zone <- terra::as.polygons(r, dissolve = TRUE)
roads <- terra::vect(matrix(c(0, 2, 4, 2), ncol = 2, byrow = TRUE),
  type = "lines", crs = "EPSG:3857")
make_road_aware_escape_zone(zone, roads, road_buffer_m = 0.1)
#> class       : SpatVector
#> geometry    : polygons
#> dimensions  : 1, 0  (geometries, attributes)
#> extent      : 0, 4, 0, 4  (xmin, xmax, ymin, ymax)
#> coord. ref. : WGS 84 / Pseudo-Mercator (EPSG:3857)