Make a mask from presence data — make_mask_from

This functions uses the presence column to create a mask to apply to the raster to define the area of interest. Two methods are available: one that uses a buffer around each presence, and one that create a convex hull around all presences (with the possibility of further adding a buffer around the hull).

Usage

make_mask_from_presence(data, method = "buffer", buffer = 0, return_sf = FALSE)

Arguments

data: An sf::sf data frame of presences..
method: the method to use to create the mask. Either 'buffer' or 'convex_hull'
buffer: the buffer to add around each presence (in the units of the crs of the data; for lat/lon, the buffer will be in meters), or around the convex hull (if method is 'convex_hull')
return_sf: whether to return the mask as an sf object (if TRUE) or as a terra::SpatVector object (if FALSE, default)

Value

a terra::SpatVector or an sf object (depending on the value of return_sf) with the mask

Details

To use terra::mask() on a raster, use return_sf = FALSE to get a terra::SpatVector object that can be used for masking.

Examples

lacerta_sf <- lacerta %>% sf::st_as_sf(coords = c("longitude", "latitude")) %>% sf::st_set_crs(4326)
land_mask <- terra::readRDS(system.file("extdata/lacerta_land_mask.rds",
package = "tidysdm"))
mask_buffer <- make_mask_from_presence(lacerta_sf, method = "buffer", buffer = 60000)
terra::plot(terra::mask(land_mask, mask_buffer))

mask_ch <- make_mask_from_presence(lacerta_sf, method = "convex_hull")
terra::plot(terra::mask(land_mask, mask_ch))