1. Grids (hgrid · topo · vgrid)

1. Grids (hgrid · topo · vgrid)#

The first step of any CrocoDash workflow is defining the spatial domain: a horizontal grid (Grid), a bathymetry (Topo), and a vertical grid (VGrid).

        flowchart LR
    HG["hgrid<br/>(Grid)"] --> C["Case(...)"]
    TP["topo<br/>(Topo)"] --> C
    VG["vgrid<br/>(VGrid)"] --> C

CrocoDash re-exports these objects from mom6_forge with no modifications, so all the details — class methods, creation patterns, file formats — live in the mom6_forge documentation. This page is a short on-ramp that points you there.

What mom6_forge gives you#

For each of the three grid objects, mom6_forge provides both programmatic and interactive construction:

Object

Programmatic API

Interactive widget

Horizontal grid (Grid)

Grid(...), Grid.from_supergrid(...)

GridCreator

Bathymetry (Topo)

Topo(...), Topo.from_topo_file(...)

TopoEditor

Vertical grid (VGrid)

VGrid.hyperbolic(...), VGrid.from_file(...)

VGridCreator

Notable features worth knowing about:

  • TopoEditor — ipywidgets-based bathymetry editor with undo/redo, version-controlled edits, and live plotting. Great for fixing isolated basins, carving channels, or smoothing coastlines before case creation.

  • Version-controlled bathymetry — Topo uses a per-domain TopoLibrary/ directory under the hood. Every edit is committed as a git-style operation, so you can replay, share, or undo bathymetry changes reproducibly.

  • Curvilinear grids — Grid.from_supergrid(...) works for both rectilinear (lon/lat) and curvilinear grids.

  • ESMF mesh + SCRIP output — the Topo object writes CICE grids, SCRIP grids, and ESMF meshes directly, which is what CESM needs for coupling.

  • Chlorophyll and runoff mapping helpers — mom6_forge.chl and mom6_forge.mapping are used internally by extract_forcings, but are also available if you need them directly.

Importing#

The only difference from vanilla mom6_forge is the import path. Replace the mom6_forge namespace with CrocoDash:

Instead of…

Use…

import mom6_forge.grid

import CrocoDash.grid

import mom6_forge.topo

import CrocoDash.topo

import mom6_forge.vgrid

import CrocoDash.vgrid

Everything else — class names, method signatures, parameters — is identical.

Next step#

Once you have your Grid, Topo, and VGrid objects ready, pass them to the Case object to move on to Case Setup:

case = cd.Case(
    ocn_grid=grid,
    ocn_topo=topo,
    ocn_vgrid=vgrid,
    ...
)

See also#

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