Create a land/ocean mask raster for track simulations

Creates a raster mask with values:

0 = ocean
1 = land

Usage

create_oceanmask(
  bbox,
  res,
  polygon,
  polygon_type = c("land", "ocean"),
  crs = "EPSG:4326",
  touches = TRUE
)

Arguments

bbox: Numeric vector of length 4: c(xmin, xmax, ymin, ymax) in lon/lat.
res: Numeric. Raster resolution in degrees (e.g., 0.01).
polygon: Spatial polygon defining either land or ocean. Either a terra::SpatVector or an sf object.
polygon_type: Character. One of c("land","ocean") indicating what polygon represents.
crs: Character. Target CRS; default is EPSG:4326.
touches: Logical. Passed to terra::rasterize(); if TRUE, cells touched by polygon boundaries are included (often preferable near coastlines).

Value

A terra::SpatRaster with values 0 (ocean) and 1 (land).

Details

The input polygon can represent either land or ocean; set polygon_type accordingly. Areas not covered by the input polygon are assigned the complementary class (land if polygon is ocean; ocean if polygon is land).