Bathymetry

Bathymetry (Topo) sits between the horizontal grid and the vertical grid: it needs a Grid to attach to (see Grids), and its max_depth typically feeds the vertical grid (also in Grids).

CrocoDash re-exports Topo unmodified from mom6_forge , the full API and editing mechanics live in the mom6_forge documentation, particularly the bathymetry notebooks (3_custom_bathy, 4_ingest_landmask, 5_modify_existing, 6_coarsen_existing, 10_cressman_interpolation) and the Topo Editor widget walkthrough (6_demo_editors, Section 2).

This notebook covers:

Section 1: remap an existing dataset (e.g. GEBCO) onto your grid
Section 2: interactive editing with TopoEditor
Section 3: load a pre-existing topo file, or build a flat/synthetic one

📖 CrocoDash grids docs · 📖 mom6_forge docs

Section 1: Remap an Existing Bathymetry Dataset¶

This needs a Grid to attach the bathymetry to. See Grids for how to build one. Here we build a small throwaway grid so this notebook runs on its own.

from CrocoDash.grid import Grid

grid = Grid(
  resolution = 0.05, # in degrees
  xstart = 278.0, # min longitude in [0, 360]
  lenx = 3.0, # longitude extent in degrees
  ystart = 7.0, # min latitude in [-90, 90]
  leny = 3.0, # latitude extent in degrees
  name = "panama1",
)

from CrocoDash.topo import Topo

topo = Topo(
    grid = grid,
    min_depth = 9.5, # in meters
)

from pathlib import Path

bathymetry_path= Path("<GEBCO>")

if not bathymetry_path.exists():
    raise FileNotFoundError("Bathymetry file not found, please replace with path to bathymetry file")

topo.set_from_dataset(
    bathymetry_path = bathymetry_path,
    longitude_coordinate_name="lon",
    latitude_coordinate_name="lat",
    vertical_coordinate_name="elevation"
)

topo.depth.plot()

Section 2: Interactive Editing (`TopoEditor`)¶

TopoEditor is an ipywidgets-based bathymetry editor with undo/redo, version-controlled edits (a per-domain TopoLibrary/ directory records every change as a git-style operation), and live plotting, useful for fixing isolated basins, carving channels, or smoothing coastlines before case creation.

%matplotlib ipympl
from CrocoDash.topo_editor import TopoEditor
TopoEditor(topo)

Section 3: Pre-Generated or Flat Bathymetry¶

Two more ways to get a Topo without remapping a dataset:

Section 3.1: load a topo file that already matches your grid.
Section 3.2: a constant-depth ocean, useful for idealized/test cases.

Section 3.1: Load a Pre-Generated Topo File¶

Use this when you already have a topography file that matches your grid, e.g. from a previous run or a shared community grid like NWA12.

from CrocoDash.grid import Grid
from CrocoDash.topo import Topo

grid = Grid.from_supergrid("<NWA_HGRID>")

bathymetry_path = "<NWA_BATHY>"

topo = Topo.from_topo_file(
    grid=grid,
    topo_file_path=bathymetry_path,
    min_depth=5,
)

topo.depth.plot()

Section 3.2: Flat Bathymetry¶

For idealized or test domains, skip remapping entirely and set a constant depth with topo.set_flat(depth), used throughout this gallery’s synthetic-domain examples (e.g. Interior OBC Segments).

flat_topo = Topo(grid, min_depth=10.0, git=False)
flat_topo.set_flat(1000.0)

Next steps¶

Once you have a Grid, Topo, and VGrid (see Grids), pass them to Case. See Case Setup.