 <a href="https://www.gebco.net/data_and_products/gridded_bathymetry_data/" class="external-link">GEBCO</a>, <a href="https://www.gebco.net/data_and_products/gridded_bathymetry_data/arctic_ocean/" class="external-link">IBCAO</a>, <a href="https://www.ncei.noaa.gov/products/etopo-global-relief-model" class="external-link">ETOPO</a> bathymetry grids downloaded from respective sources as the <code>bathy</code> argument. The bathymetry grids read from files must be in any format read by <code><a href="https://r