Get knolls base areas

Get knolls base area data in a spatial grid or polygon

Usage

get_knolls(
  spatial_grid = NULL,
  raw = FALSE,
  name = "knolls",
  antimeridian = NULL
)

Arguments

spatial_grid

`sf` or `terra::rast()` grid, e.g. created using `get_grid()`. Alternatively, if raw data is required, an `sf` polygon can be provided, e.g. created using `get_boundary()`, and set `raw = TRUE`.

raw

`logical` if TRUE, `spatial_grid` should be an `sf` polygon, and the raw data in that polygon(s) will be returned

name

`string`; name of raster or column in sf object that is returned

antimeridian

Does `spatial_grid` span the antimeridian? If so, this should be set to `TRUE`, otherwise set to `FALSE`. If set to `NULL` (default) the function will try to check if `spatial_grid` spans the antimeridian and set this appropriately.

Value

For gridded data, a `terra::rast()` or `sf` object, depending on the `spatial_grid` format. If `raw = TRUE` an `sf` object crop and intersected with the polygon supplied.

Details

Knolls are small seamounts; seamounts with peaks 200-1000 m higher than the surrounding seafloor [(Morato et al., 2008)](https://doi.org/10.3354/meps07268). The knolls base area data is from [Yesson et al. 2011](https://doi.org/10.1016/j.dsr.2011.02.004)

Examples

# Get EEZ data first 
bermuda_eez <- get_boundary(name = "Bermuda")
# Get raw knolls data for Bermuda's EEZ
knolls <- get_knolls(spatial_grid= bermuda_eez, raw = TRUE)

# Get gridded knolls data: first create a grid
bermuda_grid <- get_grid(boundary = bermuda_eez, 
  crs = '+proj=laea +lon_0=-64.8108333 +lat_0=32.3571917 +datum=WGS84 +units=m +no_defs', 
  resolution = 10000)
knolls_gridded <- get_knolls(spatial_grid = bermuda_grid)
#> although coordinates are longitude/latitude, st_intersection assumes that they
#> are planar
terra::plot(knolls_gridded)